Bisnis Petasan dan Kembang Api

[gustirangda]

Sobat, ini ada satu lagi ide kreatif yang mungkin bisa saya share kan ke teman-teman semua. Berawal dari kumpul-kumpul sesama ‘calon pengangguran’ di kampus, akhirnya kemarin coba membuat bom asap sederhana. Bom asap biasa digunakan secara luas mulai dari dunia militer, film, sampai dengan tanda SOS dalam keadaan darurat. Mau tau caranya? Sip, baca aja step by step dibawah ini!
Bahan-bahan :

• Sumbu petasan atau kembang api secukupnya
• KNO3 (Kalium Nitrat/Potasium Nitrat) 40 gram. Harganya sekitar 30 ribuan di jogja. Bisa dibeli di lab kimia terdekat atau di toko-toko yang menjual peralatan perkebunan
• Gula Pasir 60 gram
• Baking Soda 1 sendok makan
• Pewarna Organik (Organic Dye) 3 sendok makan. Disarankan memilih warna yang mencolok seperti merah atau orange
• Kertas Karton Tebal atau kaleng bekas minuman soda
• Lakban
• Kapas

Peralatan :

• Pemanas seperti kompor gas, kompor spiritus, arang, atau kompor minyak biasa pun bisa asalkan api yang dihasilkan stabil dan bisa diatur
• Panci kecil, disarankan yang sudah tidak terpakai lagi
• Sendok stainless steel atau sendok kayu
• pulpen, ranting bambu atau sumpit mie ayam

Cara Pembuatan :

1. Buatlah sebuah tabung tanpa tutup dari kertas karton dengan diameter sekitar 3 cm dan tinggi 9 cm, ketebalan sekurangnya 2 lapis karton. Tabung karton bisa diganti dengan kaleng bekas minuman soda ukuran kecil, dipotong bagian atasnya sehingga menjadi tabung tanpa tutup.
2. Hidupkan pemanas kompor gas atau spiritus sampai dengan api yang paling kecil. Tumpangkan panci diatas kompor.
3. Campurkan 40 gram KNO3 dengan gula pasir 60 gram di atas panci dan aduk dengan pelan-pelan. Awas, bahan ini mudah rusak.
4. Aduk terus campuran hingga gula dan KNO3 menjadi cairan yang lengket dan kental seperti karamel berwarna coklat kekuning-kuningan. Proses memakan waktu sekitar 10 menit. Selama itu, anda harus mengaduk terus.
5. Angkat panci dan campurkan satu sendok baking soda, aduk hingga merata. Baking soda disini berfungsi untuk memperlambat reaksi.
6. Masukkan pewarna organik sebanyak 3 sendok dan aduk hingga merata.
7. Masukkan campuran karamel ke dalam tabung karton yang sudah dibuat.
8. tancapkan pulpen, ranting bambu, atau sumpit mie ayam ditengah-tengah tabung karamel sebagai tempat sumbu. biarkan mengeras selama 1 jam.
9. Sesudah 1 jam, cabut pulpen tersebut dan masukkan sumbu petasan atau kembang api. Sumbat bagian yang longgar dengan kapas.
10. Bungkus tabung tersebut dengan lakban hitam, sisakan lubang pada bagian sumbu agar asap dapat keluar dengan lancar.
11. Selesai ! Bom siap ‘disajikan’

Catatan :

1. Asap yang dihasilkan cukup pekat, disarankan memakai masker/sapu tangan.
2. Untuk SOP keselamatan, lebih afdol memakai sarung tangan+kaca mata waktu pembuatan.
3. Jauhkan semua bahan dari anak kecil dan anak gedhe yang belum punya pikiran panjang. Dangerous material!
4. Untuk video tutorialnya bisa di liat di sini

[aljufri]

The name "stinger missile" seems to have become fairly common among pyro hobbyists to refer to the class of rockets which are spin stabilized. This means that the usual efforts to assure a predictable flight path of a rocket, which include body fins or a guide stick, can all be dispensed with. Consequently, the spin stabilized rocket is extremely easy to make. This is what makes them so much fun. Unlike a girandola project, these little jewels can be made in a few minutes and launched immediately. It's a great fix for the smoke addicted pyro who often needs to throw something together quickly. The methods presented here closely follow those first described by Warren Klofkorn some 10 years ago. His article appears in "The Best of AFN II" on page 62 and has become the standard reference for stinger missile construction. A description of my personal experience with his instructions and a few other innovations, hints and tips are included here in the hope that they might make your experience more enjoyable.
	Tooling is usually the first consideration of any new pyro project. Since the tooling for stingers is fairly simple, it doesn't cost much to buy it from professional sources. I purchased a tooling kit for the 3/4 inch stingers from Skylighter for the bargain price of $44.95 US. Shown in this picture, a machined aluminum spindle is mounted in a ramming base and held in place with a bolt through the bottom. The rammers consist of an aluminum rod with a hole in it for pressing the black powder fuel around the spindle and a solid one for pressing the fuel and delay composition above the spindle.
	This is a close-up of the jig used to position the side vent hole in the stinger body tube. This hole is used to create tangential thrust which will cause the rocket to spin as it flies. The angular momentum of the spinning rocket is what stabilizes it instead of relying upon positioning the center of pressure behind the center of gravity, as accomplished by fins or sticks. This jig helps to accurately position the vent hole to consistently achieve a good spin. The desired location of this vent hole is just above the clay nozzle and in a direction that is at a tangent to the inside surface of the tube. This jig may look a little different from the present Skylighter product, but the function is identical.
	To adjust the jig for the size of stinger you plan to make, you must first loosen the two screws until they allow the guide hole plate to slide relative to the angle piece. First adjust the screws to be slightly snug so that the two jig pieces aren't overly floppy, but will slide with a little effort.
	Now get a piece of stinger tubing and hold it against the jig as shown. Place the 9/64 drill bit (provided with the stinger tool kit) in the guide hole and check the alignment as illustrated in the picture. The drill bit should be positioned so that its side flutes are even with the inside wall of the tube. If this verbal description is not clear, just look at the picture. As they say, it's worth a thousand words. Now, if your alignment isn't correct, just slide the jig pieces until it is, and then tighten the screws. This alignment will assure that, when drilling the side vent hole, the drill bit will emerge at the right place on the inside surface of the tube. With the vent hole aligned correctly, you will achieve the best thrust angle to maximize spin and stability. Be sure that your adjustment screws are in the same places in the two slots, assuring that the two jig pieces are parallel to each other. Another good tip to use at this point is to put a small piece of tape on the drill bit to mark the proper depth of insertion into the guide hole. The proper depth is also shown in the picture. If the drill bit is allowed to go any further into the guide hole, it will begin to drill into the opposite wall of the tube, causing undesirable weakening at that point. With this done, the jig set up is complete and you're ready to get your hands dirty and have some real pyro fun.
	Construction of the stinger starts by preparing the body tube. A typical 1 pound rocket tube may be used. The Skylighter TU1068 is a good example. It measures 3/4 inch ID, 1-1/4 inch OD and 7-1/2 inches long. You can save money if you buy the longer TU1065 from which you can cut as many as 9 stinger tubes. Either way, a tube must be cut to a length that depends on what heading is planned for the payload of the rocket. Cutting these heavy tubes is best accomplished by using a table or radial arm saw because a clean, square end is desirable. A length of 3 inches is typical for a rocket which contains some colored star composition for delay and some flash powder for a salute finish. Another option is to add a header extension filled with stars and some burst composition. When this option is chosen, the body tube can be cut a little shorter, enabling three stingers to be made from a single 1 pound rocket tube. The construction of these headers will be covered later.
	With the tube cut to the desired length, it is placed over the spindle on the spindle base and a carefully measured amount of nozzle clay is poured into the tube. A small funnel of some sort, as shown on the floor in the picture, is very helpful in accomplishing this. Klofkorn's original article advocated the use of 4.3 cc of powdered Hawthorne Bond clay for the rocket nozzle. I use a 60%/40% mix of bentonite and kyanite treated with an additional 5% of toilet seal wax dissolved in Coleman fuel. Instead of using a volume measurement for the nozzle clay, I recommend that you use a weight measurement so that a consistent nozzle length is achieved. The importance of doing this will become evident shortly. Stay tuned. If you are not using a hydraulic press, the nozzle clay is compacted by administering about a dozen firm blows (this is called "ramming") with a mallet of some sort, as shown in this picture.� Although a little bulge in the tube wall can be desirable after ramming or pressing, be careful not to split the tube.
	Before drilling the side vent hole in the body tube, a mark must be made on the outside of the tube to indicate where the top of the nozzle is located. Start by applying a piece of masking tape to the rammer so a mark can be easily made on it. Then place the rammer in the body tube until it seats against the nozzle. Now make a mark on the masking tape, as shown. Of course, if you were really on the ball, you could do this right after you finished ramming the nozzle clay, in the step above.
	Next, remove the rammer and hold it against the outside of the tube with the mark you just made even with the top of the tube. Make a mark on the body tube at the bottom of the rammer. This mark should now indicate where the top of the nozzle is inside the tube.
	Now the tube is held in the drilling jig, as shown. The guide hole should be located so that the side vent hole will be drilled just above the nozzle. In case you haven't figured it out, you should remove the tube from the spindle base before you drill the side vent hole.
	Hold the tube in the drilling jig in one hand, properly positioned as shown in this picture.� Then the hole is slowly drilled with a hand drill, taking care to firmly grip the tube in the jig so that it doesn't move. Again, note the piece of tape on the drill bit, which indicates the proper depth for the drill bit in the guide hole. Now pay close attention. Here comes the nifty tip you've been waiting for. Once the location of the top of the nozzle has been established, it should be measured and preserved in your notebook. This measurement can be used in all future stingers with the assumption that it will always be accurate. The assumption is a safe one to make if your nozzles are always made the same way with exactly the same compression and same amount of clay. The significance is that the side vent hole can be drilled before the nozzle is rammed, eliminating the need to remove the tube from the spindle to locate the top of the nozzle and drill the hole after nozzle ramming. It's a nice little time savings.
	The vent hole can be made more impervious to hot exhaust gasses by treating it with a few drops of sodium silicate solution, as shown in this picture. An eye dropper is used to put the silicate into the hole. A toothpick or small nail is then used to spread it around in the hole and prevent blockage or constriction of the hole. Some of my impatient pyro friends skip this step to avoid waiting for the required 20 minutes for the silicate to dry in the vent hole. Their stingers still seem to fly just fine, albeit possibly not quite as high.
	This picture illustrates the use of a typical rocket press to form the nozzle and load the black powder fuel. Note that the black powder you use must be very fine black powder: either commercial Meal-D or homemade, ball-milled, fine black powder. When a hydraulic press is used instead of a mallet, a reinforcing sleeve is a good idea to avoid deforming the rocket tube. Which ever method is used to load the black powder fuel, a little scoop, as shown in the hand ramming picture above, is handy for measuring out the fuel for each pressed increment. I made mine by hot gluing the bottom section of a film canister to a small garden marker stick. The black powder fuel must be compacted in the tube in about 4 or 5 increments, each of which should be no longer than the inside diameter of your stinger tube. For the black powder fuel, I use the same milled meal that I use to make a good lift powder. It contains willow charcoal to make a very hot rocket fuel. This fuel would be too hot for a standard 1 pound rocket, but for stingers it works very well because the rocket core is considerably shorter. I have notice, however, that in the case of the larger 3 pound stingers, my home-made black powder is a little too hot. I experienced a few explosions immediately upon ignition until I cooled the fuel down a little with a few percent of mineral oil. As with most black powder based rockets, you may need to experiment a little to dial in the proper burn rate for your stingers.
	After the rocket has been charged with its black powder propellant, some delay composition should be loaded above it to allow the stinger to reach its apogee. Otherwise, your stingers will activate their payloads at very low altitudes because the actual thrust burn only lasts about 1 second. The following green star composition is suggested by Klofkorn as a safe and compatible delay element: Barium Nitrate Potassium Perchlorate� Parlon� Red Gum� Soluble glutinous rice starch 28.3% 47.2% 4.7% 14.2% 5.6% Somewhere between 6 cc and 9 cc of this composition, damped with a sparing amount of alcohol, is pressed into the top of the tube using moderate pressure only. It is a good idea to give this delay composition a little drying time before adding the final heading to the rocket. The diagram at the left shows the internal structure of the missiles after a heading of flash powder has been added. There is nothing sacred about this particular way of making a delay. Dextrin can be substituted for the rice starch or a totally different delay composition can be used. I am a little partial to some of the glitter formulas, myself, such as Winokur #39.
	Now we are ready to talk about the various heading options for our stingers. After all, what's the point of making a rocket that just spins as it flies if it doesn't do something cool at the end of its flight? The easiest heading is 3 cc of flash powder in the remaining cavity of the stinger tube. This is finished by gluing (white or Elmer's glue) a 3/4 inch end plug that just touches the flash powder enough to keep it from shifting during the spinning ascent. An easy shell header with stars can be constructed using a 1-1/2 inch length of paper tube whose inside dimension is 1-1/4 inches. This tube is glued to the stinger tube with a 1/2 inch overlap. The expanded cavity now has more room to accommodate a larger payload of stars and burst. The payload space needs to be filled completely and firmly packed so that no asymmetries can be created when the stinger spins. The cavity can be closed in a variety of ways. A typical end plug or cap will do the trick, but if you want to maximize your payload space, a molded nose cone can be used. The nose cone shown in the picture is molded from craft paper pulp bound with CMC binder. An example of each of these header options is shown in the picture. Again, whatever header is chosen, care must be taken to avoid asymmetries, or your stingers will wobble all over the sky.
	Now a fuse is added to the side vent hole. A 1/8 inch drill bit (1/64th smaller than the one used to drill the hole in the tube to start with) is inserted into the hole and twisted gently by hand to open a small cavity in the black powder fuel grain. A glob of Meal D wetted with nitrocellulose lacquer is placed on the end of a 3-inch length of visco fuse. The globbed end is inserted into the vent hole as far as it will go. The lacquer will dry shortly and secure the fuse in place. I don't bother to bend it against the tube wall and affix it with tape, as recommended by Klofkorn. This practice has damaged the somewhat brittle visco and has caused failure of ignition on some of my stingers. If you use a more flexible fuse, this may still be a good idea to make the fuse more secure during storage and transport.
	A little bit of added stability at lift off can be achieved by gluing a custom reinforcement to the business end of the stinger. This is accomplished by tracing a circle around a stinger tube on a piece of strong tissue paper. A notebook paper hole reinforcement is then glued to the center of the circle. The circle is cut out and glued to the nozzle end of the stinger as shown in the picture. The launch spindle will be inserted through the hole of the reinforcement at launch time. The reinforcement helps the stinger spin about its central axis without wobbling. Another possibility I have seen used for this purpose is a standard paper end plug with a hole punched in it. The end plug is not glued into place so it will easily be blown out when the stinger flies. These end plugs may usually be re-used a few times before they become too badly charred.
	The stinger missile requires a custom launch pin to support it prior to launch and during initial spin-up of the device. This can be as simple as a nail driven through a good sized piece of wood to give it a solid footing during launch. The last thing you want when these things start spinning is for the launch stand to tip over and send an angry stinger missile into your terrified audience. The nail is rounded at the end by a file to provide a good pivot point at the top of your stinger core. This picture shows a typical launch stand with two launch pins, one supporting a finished missile ready for launch. A little decorative paper has been added to give it a festive flair. All that remains is to light the fuse, retire to a safe distance and feel the rush these marvelous little rockets give to their creator and his audience.
Tips and suggestions for further enhancements: �������� After a suggestion from Lindsay Greene, I tried adding 3% of 40-200 mesh spherical titanium to the black powder fuel. It creates a beautiful, cork screw trail of bright golden sparks as the stinger ascends. It is a very impressive effect with little extra effort. The only drawback is that the titanium causes a little extra wear on your tooling and launch spindle. �������� Another possible time saver is to insert the fuse into the side vent hole before ramming the black powder. The powder will compress around the fuse and help secure it in place. �������� The launch spindle must be long enough to suspend the stinger above the launch base. If the bottom of the stinger is touching the wooden base, it will interfere with the stinger's ability to spin on the spindle. �������� An exciting recent innovation is to use flying fish fuse in the header. A bundle of short lengths of this fuse will ignite to a make a swarm of little wigglies all over the sky. One end of each fuse is primed to aid ignition and the other end is coated to inhibit ignition. This special fuse can be purchased from Skylighter.

VISIT OUR NEWSLETTER ARCHIVE
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Now obviously, our more recent articles contain our latest news, but this wealth of fireworks know-how is still highly recommended reading. You�ll find lots of step-by-step instructions for making all kinds of fireworks including stars, dragon eggs, comets, spin stabilized rockets, strobe rockets, whistle rockets, black powder rockets, aerial shells, fountains, Class C fireworks displays, volcanoes, smokes, fuses, electric matches, tourbillions, saxons, special effects fireballs, colored liquid fire, colored fireballs, mines, and much, much more.

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Tired of reading yet? Well, quit readin' and go out and LIGHT something!

Harry Gilliam -- Chief Cook & Bottle Washer

[aljufri]

LARGE RELOADABLE GLITTER COMETS

By Ned Gorski


Safety

Whether you are new to fireworking or a seasoned veteran it always pays to regularly study good pyro-safety guidelines and to notice whether or not your work habits are conforming to those recommendations.

Please refer to these links:

Fireworks Safety 101 by Kyle Kepley, intro by Ned Gorski

Fireworks Safety Manual, a collection of essays by Bill Ofca



Introduction

In Fireworks Tips #111, How to Make Gold Glitter Comets I described the process of making relatively small, single-shot gold-glitter comets. These were designed to be fired out of a star gun or a small mortar, with the black powder lift charge preloaded into the bottom of the mortar, and a piece of Visco fuse inserted into the bottom of the gun.

In this article I want to take that process one step further, and show how to make reloadable comets, similar in construction to festival-ball and aerial fireworks shells. This construction technique allows the comets to be easily and quickly loaded and fired, and reloaded as desired.

I'll show you how to construct 1.5-inch, 3-inch, and 4-inch comets. The smaller ones can be fired out of a typical 1.75-inch festival-ball shell mortar PL3170. The 3-inchers can be fired out of a 3-inch mortar PL3183, and the 4-inchers out of a 4-inch gun PL3184.

Warning: Fireworks devices such as comets and standard aerial shells are only safely fired out of mortars constructed of paper, fiberglass, or HDPE plastic. Never fire these devices out of improvised and unsafe mortars constructed of PVC pipe or materials other than those listed above.

The 3-inch comets actually measure 2.5 inches OD, and the 4-inch ones measure 3.5 inches OD. The 1.5-inch comets do measure 1.5 inches OD, and are to be fired out of a mortar between 1.75 and 2 inches ID.

There is perhaps no simpler a device than a comet, but a beautiful gold-glitter one never fails to catch the crowd's attention and impress them. The smaller ones described here are perfect for that backyard, consumer-type fireworks display, and the larger ones can fill the sky during any large, professional-type show.

There are also simple, fast-burning charcoal compositions, which can be used for this type of comet. They leave a bushy, orange spark trail while ascending into the sky.



Gold Glitter Comet Composition


In this particular project, I'll be using the D1 Gold-Glitter composition that was demonstrated in the article cited above. If you've been following along with the articles this year, the procedure for mixing up a comp like this will sound very familiar.

To determine how much of this composition to mix up, I need to plan the comets that I am about to make. Each size comet, if it is pressed with the hydraulic press, uses the following amount of the dampened composition:

Size of comet	Amount of composition
1.5-inch diameter, 1.5 inches long	2.75 ounces
2.5-inch diameter, 2.5 inches long	12 ounces
3.5-inch diameter, 3.5 inches long	32 ounces

Note: The 2.5 and 3.5-inch comets have to be pressed with a hydraulic press in order to achieve dense consolidation of the composition. The 1.5-inch comets can be hand rammed using a pounding-post and mallet, or they can be pressed hydraulically.

If they are hand rammed, though, only 2.25 ounces of composition will be able to be consolidated into a 1.5-inch long comet. Hand ramming simply will not achieve quite the density that a press can.

I plan on making four of the 1.5 inchers, and one each of the larger ones. So, I need to make 55 ounces of the damp composition. I will be adding 5% (2.75 ounces) of water to the comp to dampen it, so I'll actually end up with 57.75 ounces of the damp composition. This is 2.75 ounces more than I need for my planned comets, so I think I'll simply press one extra of the 1.5 inchers rather than complicate the math involved. It never hurts to have an extra comet.

In the small glitter comet article, I described starting with a black powder meal base. This time I'll start with the individual raw chemicals, which works just about as well.

D1 Gold Glitter formula	%	55 ounce batch
Potassium nitrate	0.53	29.15 ounces
Sulfur	0.18	9.9 ounces
Charcoal, airfloat	0.11	6.05 ounces
Aluminum, atomized, 325 mesh	0.07	3.85 ounces
Sodium bicarbonate	0.07	3.85 ounces
Dextrin	0.04	2.2 ounces

I weigh each chemical out individually, and make sure each one, except the metal, will pass through the 100-mesh screen. If it won't, I'll grind it in the coffee grinder until it will all pass through the screen. I never put metals through the fine screens.

A coffee grinder is used to mill individual chemicals only, and once it has been used for an oxidizer such as the potassium nitrate, it is never used for a fuel such as the charcoal. A separate grinder is used for fuels.

The chemicals are all added to a plastic tub and shaken to mix them. Then the mix is passed three times through a 20-mesh kitchen colander and mixed once again in the tub.

At this point, I weigh the mixed composition to make sure its weight comes up to the desired 55 ounces. This step ensures that I weighed each component correctly, and that I didn't leave anything out. I can't tell you how many mistakes, and the resulting poorly-performing devices, this step can avoid. In actuality the total composition weight is typically a tenth ounce or so lighter than the total I was shooting for, due to some loss to airborne dust from the lighter components like charcoal.

2.75 ounces of water is added to the mix and it is all shaken in the tub again. Then it is passed through the colander again to completely integrate the water. One final shaking in the pail completes the preparation of the composition.



Pressing Comets


As I said, the 1.5-inch comets can be either hand-rammed or pressed in a small hydraulic press. I weigh out either 2.25 ounces of the composition, for hand-ramming, or 2.75 ounces for pressing. The comp is poured into the comet pump sleeve and the comet is either rammed or pressed.


Hand-Ramming, and Hydraulic Pressing, 1.5-Inch Glitter Comets

The same is done for the 2.5-inch and 3.5-inch comets; comets of these sizes must be pressed hydraulically.


Pressing 2.5-Inch and 3.5-Inch Glitter Comets

When using the press, I apply about 5000 pounds of force on the1.5-inch comet pump, which amounts to about 3000 psi on the composition.

With the larger pumps, I'll apply about 10,000 pounds of force, which applies about 2000 psi on the comp in the 2.5-inch pump, and about 1000 psi on the comp in the 3.5-inch one. This is enough pressure if I allow the press to "dwell" for a minute or two on the pump, slowly compressing the comet, while I regularly pump the pressure back up.

One of the things I really love about this glitter composition is that once it has been pressed, it forms a rock-solid comet. This also makes the comets a bit difficult to extract from the pumps once they have been pressed (no problem extracting a hand-rammed comet, though). A comet extraction-sleeve can make this final process much easier. The sleeve is simply a hollow cylinder that the pump sits in the top of, and into which the comet is pushed with the press.


Using an Extraction-Sleeve to Push a Comet Out of the Pump


1.5-Inch, 2.5-Inch, and 3.5-Inch Gold Glitter Comets



Drying the Comets


Since these comets only contain 5% water, they come out of the pump relatively dry, and pieces of them can actually be lit and tossed even before they are dried.

But, because they contain potassium nitrate, fine aluminum, and sodium bicarbonate, there can be unwanted chemical reactions if they are allowed to get too hot before they dry a bit. So, I air dry them in the shade for a few days before they are put into the drying chamber for a few more days to complete the drying process.

You can notice on the tops of the two large comets in the photo above that I've written their weights with a Sharpie marker. I did this immediately after pressing them, and then once a day as they dry. Once their weight equals 0.95 of the original weight, I know all the water is gone and they are completely dry.



Priming the Comets


You can also see in the above photo that the 1.5-inch comets have been primed, per the instructions in Fireworks Tips #111. I do prime both ends of these comets, rather than only one end, which I did in the original article because the comets could be used as rising tails on shells. Priming both ends ensures that the flame propagates quickly to the whole comet's surface when it is ignited.


Priming Comets



Finishing the Comets


In Fireworks Tips #114, Making Mines, I illustrated a simple "piston" which is used to propel all the mine-stars out of the mortar at one time, and straight up into the sky.

I'll use a similar piston under each of these comets.

"Why", you might ask.

Often, when you see a large comet shot out of a mortar, you'll see some small, lit fragments come out of the mouth of the gun with the main comet, or else you might see the whole comet split into two or three pieces, ruining its effect.

I envision these defects to be the result of the impact of the initial blast from the black powder lift hitting the bottom of the comet, possibly chipping the bottom edges off of it, combined with the comet twisting as it is propelled up the mortar. In that case, the comet is wedged in the mortar, and suffers damage due to those stresses. All of this, of course, occurs in a matter of milliseconds.

To prevent such damage, and to get the comet out of the gun in one piece, I employ the piston. This is made out of two cardboard discs, with a hole in the center of each, and a length of cardboard tube glued between them. The discs and tube are the same OD as the comet, and the tube is about that same distance long.

None of these dimensions is extremely critical, though. While I like to have the discs the same diameter as the comet, the tube can be a bit smaller or larger, and the tube can be a bit shorter than the comet's OD. This ain't rocket science. It's comet science!

Unlike the pistons I showed in the article on making mines, with these comet pistons I only put one hole in the center of each disc to allow fire to get to the comet easily. I also only use the one, large tube, instead of the two tubes used in the mine pistons.


Cardboard Pistons Sized to Be Used Under Each Size Comet

I prepare black powder lift bags, and insert quickmatch leaders, once again as described in the mines article. The amount of lift for each comet size is as follows:

1.5-inch comet	0.3 ounce of FFg or FFFg sporting black powder
3-inch comet	0.75 ounce 2FA black powder
4-inch comet	1.5 ounces 2FA black powder

Black Powder Lift Charge, Baggie, and Quickmatch Fuse Leader

For the quickmatch fuse leader, commercial quickmatch, homemade quickmatch, or fast-fuse wrapped with aluminum foil duct tape may be used.

The lift charge and leader, the piston, and the comet are then wrapped up in two turns of kraft paper, which is glued to itself. The ends of this wrapper are then tied closed with clove hitches, and the excess paper is trimmed from the bottom. The size of paper for each size comet is:

1.5-inch	8x11
3-inch	11x18
4-inch	16x25

Kraft Paper Wrapping the Comet, Piston, and Lift Charge

Visco fuse is installed into the quickmatch leader and taped in place. The leader is then S-folded and tied to keep it neat until the comet is loaded into a mortar.


Finished 1.5-Inch Gold Glitter Comet



Results


Here's a photo of one of the 1.5-inch comets in flight. If you click on it you can see a video of it in action.


1.5-Inch Gold Glitter Comet Ascending

The second comet in the video is made with a slightly different formula I came up with by modifying and combining a couple of other formulae. It burns a bit more slowly (yes, the comet did burn out before it hit the ground) and the tail is a longer, slightly more delayed glitter, which sparks like a Senko Hanabi sparkler. I've labeled this glitter formula N1.

You can see that one of the advantages of this formula is that with a longer burn time, comets made with it can be pumped about 2/3 as long as their diameter (The comet in the video was 1.5 inches long, which I'd shorten to 1 inch next time). So, it's a bit more economical to make and use.

N1 Gold Glitter formula	%	55 ounce batch
Potassium nitrate	0.51	28.05 ounces
Sulfur	0.15	8.25 ounces
Charcoal, airfloat	0.10	5.5 ounces
Aluminum, atomized, 325 mesh	0.08	4.4 ounces
Sodium bicarbonate	0.12	6.6 ounces
Dextrin	0.04	2.2 ounces

Try both formulas and see what you think. I will say that when one of the two-pound, 4-inch D1 babies is fired, it's hard to take your eyes off of it. Very impressive, indeed!

So, you have your homework. Two formulas to play with, and three different sizes to make.

Have fun and stay green,

[aljufri]

Ned just got back from the Pyrotechnics Guild International's (PGI) week long convention in Gillette, Wyoming. He won a passel of trophies. Here's Harry with Ned right after he won:



Ned's working on an article on the PGI convention for you. If you aren't a PGI member and/or have never been to a PGI convention, you are missing the Olympics of fireworks. For instance, here're a couple of strings of firecrackers, 4 million of them, being readied for one evening's festivities.



Were I you (and thank God I am not!), I would join the PGI immediately so as to be able to partake of their next convention, the 2nd week of every August. It is the most fun thing I do vertically. When I get back from one, I usually need a vacation to recover from all the fun. I am not making that up.

This week Nedski brings you two projects. First he'll show you how to use a star gun to test the performance of your stars. He'll also show you how to make a really creative repeater (or "cake") using a star gun. Check out the little fireworks display video to see a display that you can make in 10 minutes or less. And you can reuse the star gun over and over.

Ned has also included a project which shows you how to make gold glitter comets. These easy-to-make, gold glitter comets are a great project for beginners or experienced fireworks makers. They make for a beautiful show by themselves and can be used to add flair to your homemade shells and rockets.

Comets, especially glitter comets, have always been a favorite effect for me. One of my most memorable moments in fireworks was shooting 3-inch, gold glitter comets as part of a wedding display. As each comet thumped into the air I was engulfed in golden fireflies of glitter. To this day that wonderful experience sticks with me. Here's hoping your own glitter comets will leave you with such a lasting impression.

Without a doubt after reading through the articles below you'll want one of Skylighter's handy-dandy star guns of your very own. Lucky for you we'll include a really ugly one free if you are one of the first 30 people to take advantage of this week's special offer.


- Harry Gilliam & Brian Paonessa



USING A STAR GUN
Testing Stars and Making a Reusable "Cake"

By Ned Gorski


Safety

Whether you are new to fireworking or a seasoned veteran it always pays to regularly study good pyro-safety guidelines and to notice whether or not your work habits are conforming to those recommendations.

Please refer to these links:

Fireworks Safety 101 by Kyle Kepley, intro by Ned Gorski

Fireworks Safety Manual, a collection of essays by Bill Ofca



Introduction

Two separate events have led me to explore this subject.

Harry emailed me and said that Skylighter had received a shipment of functional, but ugly, star testing guns. He said that he was willing to make folks a great deal on them if I could find a way to illustrate the need for them and how to put them to good use.

I said that I could easily do that, and that I had in mind a bonus, creative way to put them to use.

Additionally, a fellow pyro on Passfire.com was recently mentioning that he was having problems with some stars he had made. He related that he had ignited some of them while they were sitting on the ground, and although they had burnt all the way through, there was not much effect from them and they had left a large ash on the ground ounce they had gone out.

So, all of that came together, and this little article is the result.



Why is a Star Gun Necessary?


Well, technically it's not.

I've lit and thrown many stars to test-burn them in the air, and usually could do so without burning my fingers if I licked them first. Sometimes I'd grab the leather glove, but then sometimes I was too lazy for that move.

I have made Super Bottle-Rockets using Steve Majdali's tooling, available in the ads in the back of the PGI Bulletin. Taping a test-star atop one of these nifty little rockets is a great way to get the star way up in the air where it is ignited. But, making a rocket to test each star can become a bit too much work.

Way back when, I got the bright idea of getting a slingshot, taping a piece of visco fuse to a star, loading it all into the slingshot, firing up the visco, pulling back on the rubbers, waiting until the star just ignited, and letting 'er fly. I just knew I'd invented a new useful pyro device. Even called it my "Kentucky star gun."

I posted my "unique" invention on a pyro discussion list, and a well known fireworker responded that he'd been doing just that for years, and that he had some good welder's gloves (which covered the arm in addition to the hand), which he could sell me, and which were handy for that operation.

Darn. I'd reinvented the wheel once again. That happens a lot in hobbyist fireworking.

But, with all these devices, the idea is to test-burn a star or comet flying through the air at some distance from us.

Often color stars don't show their true colors if we are too close to them while they are burning. They'll look quite different at a distance of 100 feet. And they burn differently when flying through the air than they do sitting still.

For instance, willow stars and glitter stars won't create their unique effects at all if they are just sitting on the ground burning. But put them up flying through the air, and we can begin to appreciate their effects and visualize what hundreds of them flying out of a shell-burst will look like.

And, honestly, a slingshot or hand-tossing will not get the star very far from me nor very high in the air. They will often burn me. If half of my attention is on not getting burnt. I won't really focus on noticing how the star performs.

Enter the tried and true star gun.


Star Gun and Accessories



Using a Star Gun


My star gun has 5 tubes on it: 3/8-inch, 1/2-inch, 5/8-inch, 7/8-inch, and 1 1/8-inch inside diameters.

Using FFg or FFFg sporting grade black powder, I use lift powder loads as follows:

3/8-inch	Shallow 1/8 teaspoonful
1/2-inch	Flat 1/8 teaspoonful
5/8-inch	Heaping 1/8 teaspoonful
7/8-inch	Flat 1/4 teaspoonful
1 1/8-inch	Heaping 1/4 teaspoonful

To test a star, I determine which of the tubes will be a close fit for the star, while still allowing it to freely fall to the bottom of the tube. Occasionally it is necessary to persuade the star to get to the tube bottom with a thin wood dowel.

I insert 3 or 4 inches of Visco fuse into the tube's fuse hole, drop the correct amount of lift powder into the tube through a funnel, and insert the star.

Fire up the Visco, retreat, and prepare to observe the test star in flight.

Heck, single one-inch comets fired out of the large tube can be a little show all in themselves if it's a night when I simply must "smell the smoke" from something.



A Special Little Project Using the Star Gun


OK, that's using a star gun for what God intended it to be used for, but now let's get creative.

I got to thinking that a star gun could be used to create a small 5 shot repeater cake device, progressing from the smaller tubes up to the largest of them, and making an increasingly impressive little display in the process.

Stars in ever-increasing sizes could easily be rigged up to create such a cake.

But I have a complete assortment of Skylighter special effects fuses: falling leaves and flying fish in various effects and colors. Why not play with these a bit to see what would make the most fun and impressive little show?

I'll test these fuses one at a time to see which of them I like best, and which light best when shot, unprimed, out of the star gun.

First I insert the 4-inch piece of Visco fuse, and then dump the correct amount of black powder into the tube. Then I tip the star gun over, keeping the mouths of the tubes slightly higher than their fused ends.

I'm thinking that about 3 seconds of burn time for the special-effects fuse will be a good display duration. The burn time is shown on the Skylighter label for each fuse. In this case I'm testing red-crackling flying-fish fuse, which burns at about 1.9 seconds per inch, so I mark the bundle of fuse at 1.5 inches with a Sharpie.


Star Gun, Loaded with Visco Fuse and Black Powder, and with Flying Fish Fuse Inserted

Then I cut the flying-fish fuse with my anvil-cutters, and push the fuse into the tube with a wooden dowel.


Cutting Flying-Fish Fuse and Inserting It into Tube with Dowel

With this particular fuse, ignition was very good as all the fuse lit when it came out of the star gun. The display was very nice, and the fuse burned out just before it came back down to the ground.

Warning: I do not reload the star gun in my pyro shop or anywhere else where I am around pyrotechnic devices. The star gun may still have a glowing ember in it and I don't want flaming black powder to be ejected from it, along with a star or fish-fuse inside my shop. I treat the star gun as if it could go off at any time once it has been fired once.

The rest of the special effects fuses worked as follows:

The falling leaves fuses really don't work well in this little device. They burn too long and come back to the ground before creating their signature effect.

All of the flying fish fuses worked well, but one-inch lengths worked better than the one-and-a-half inch pieces. The shorter lengths ensured that they burnt in the air rather than on the ground.



Fusing the star-gun to make it a "repeater"


The first thing I did was plan a route that the fuse would take. Then I drilled the bottoms of the star-gun tubes to allow the fuse to pass through them on that route. The center tube fuse-hole was left as-is.

The first time I constructed the repeating cake, I used fast-visco fuse as shown in the photo below.


Star Gun Cake Fused with Fast-Visco Fuse

This configuration burned a little too quickly for my tastes, and there was not much delay between the last two shots because of the short length of fuse in that section.

So, I constructed the cake again using Chinese Visco fuse, as shown here.


Star Gun Cake Fused with Chinese Visco Fuse

This configuration burned much more to my liking, and the extra fuse between the final two shots lengthened the delay between them.


Click Image to See a Video of the Star-gun, Flying-Fish-Fuse Cake in Action.

Stay Green and Have Fun!
Ned

ngorski@skylighter.com



HOW TO MAKE GOLD GLITTER COMETS,
Use Them as Standalone Comets or Rising Tails on Shells

By Ned Gorski


Introduction

One of my favorite effects is a nice gold glitter comet.

This is also one of the easiest and most impressive beginner pyro projects. Make some homemade black powder and one of these simple projectiles, and you are ready to impress the folks around you. And you made it all yourself!

This is also the simplest and most effective rising effect to put on my aerial fireworks shells. The shell is launched out of the mortar and leaves a beautiful glittering gold tail as it ascends skyward. Just as the comet tail burns out, the shell bursts. The rising effect effectively doubles the display time of the shell, and fills the sky all the way from the ground to the starburst. A tail also helps to point the spectators' eyes at the exact spot where the shell is about to break.

Some master rocketeers put these comets on top of their rocket headings. The comet is ignited at the same time as the rocket, and leaves a beautiful glitter tail as the rocket ascends. I'll be detailing this method in a future newsletter article.

It is also very easy to pop a bunch of these little comets out using a half-inch star-plate, and put them into a small ball shell like the 4-inch plastic shells we built in Fireworks Tips #99. The combination of some color stars and these glitter comets makes a beautiful starburst.

Note: The difference between stars and comets is a subtle one. Typically comets are fired individually, and stars are shot out of a device in a cluster.

I have a favorite gold glitter formula which I have been using for years in both stand-alone comets and as shell tails. Anytime I fire something made with this formula someone is sure to ask me what it was and how they can make it, too. This glitter is a slightly modified version of the Gold Twinklers found in Ofca's Mastering Cut Stars, and in Weingart's Pyrotechnics.

This formula is relatively expensive though, because of the chemicals it uses. There is a much less expensive gold glitter formulation which does not use chemicals which cost as much, but which also produces a beautiful effect. This glitter is a slightly modified version of one called D1.

I'll be using both of these formulae in this project.



The Comet Pump


Besides the formulated glitter compound, one tool is essential for pumping comets: the comet pump.


Star Plate and a Variety of Comet Pumps

The black individual comet pump and star plate shown in the photo are treated aluminum. The other pumps shown are aluminum, brass, and homemade, PVC-pipe-and-wood pumps.

It's simple and inexpensive to make a 3/4-inch or 1-inch homemade comet pump as shown above. Start by going to Home Depot and getting the correct size oak dowel, a length of the corresponding size of PVC plumbing pipe, and 3 hose clamps which fit the outside of the pipe. (You can buy ready-made comet pumps from Skylighter. Skylighter pumps are rugged brass or aluminum and will typically last a lifetime. They are faster and easier to use than homemade comet pumps.)

Then cut a 6-inch length of the dowel, and a 5-inch length of the pipe, preferably with either a hand miter box or a power one to insure good, square cuts.

Using a hacksaw, slice about halfway up one side of the pipe, and remove enough of that slice of pipe so that it fits the dowel snugly at the sliced end when the gap is closed.

Sand the rough edges of the pipe and dowel, and make sure one end of the dowel is nice and square and smooth. Either seal this end with polyurethane, or cover it with a disc of aluminum-foil duct tape.


Making a Homemade Comet Pump



Mixing the Comet Composition


The Gold Twinkler formula is as follows:

Component	Percentage	Ounces
Black powder meal	0.68	5 ounces
Atomized aluminum	0.08	0.6 ounces	(I'm using Skylighter #CH0103)
Antimony trisulfide	0.08	0.6 ounces	(either dark-pyro or chinese-needle)
Sodium oxalate	0.11	0.8 ounces
Dextrin	0.05	0.4 ounces
Total batch weight:		7.4 ounces

The D1 formula is:

Component	Percentage	Ounces
Black powder meal	0.71	5 ounces
Sulfur	0.11	0.8 ounces
Atomized aluminum	0.07	0.5 ounces	(same aluminum as above)
Sodium bicarbonate	0.07	0.5 ounces
Dextrin	0.04	0.3 ounces
Total batch weight:		7.1 ounces

I'm planning on making one batch of each formula to compare with each other. Therefore I need a total of 10 ounces of the homemade, black powder meal. This will include:


7.5 ounces of potassium nitrate
1.5 ounces of airfloat charcoal
1 ounce of sulfur


To make the BP meal, I screen the potassium nitrate through a 100 mesh screen, and then screen all the chemicals together twice through the same screen to thoroughly mix them together.

Then I add 1/2 cup of denatured alcohol to the dry chemicals to form a damp ball of putty, which I screen through my 1/4-inch screen onto kraft paper to dry overnight.

Note: Alcohol fumes are combustible. I dry these granules outdoors to prevent the fumes from collecting and igniting.


Mixing Black Powder Chemicals Through 100 Mesh Screen, and Granulating Dampened Composition Through 4 Mesh Screen

When the black powder granules are dry, I screen them again through a 12 mesh screen or a wire-mesh kitchen colander. I then have a black powder meal which ranges from fine dust up through 12 mesh granules.

To complete the compositions, I split my meal powder batch into two, 5 ounce halves. I then weigh out the rest of my individual ingredients. I don't screen the aluminum or antimony trisulfide, but I do screen the rest of the ingredients for each batch through my 100 mesh screen.

Then I put all the ingredients for each batch into a plastic tub, attach the lid, and shake vigorously to thoroughly mix the ingredients.

Using a small, trigger-operated, garden spray-bottle, I add just enough water to knock the dust down and start to make the composition not quite as free-flowing. I work the water into the powder with gloved hands and by capping the plastic tub and shaking it. Each batch took 0.35 ounces of the water, which is about 5% by weight.

Note: It is a good idea to used bottled, distilled water to dampen compositions containing aluminum and potassium nitrate. This helps to prevent reactions between the two chemicals. One person's tap water might be fine to use, and another's might cause problems.



Ramming Glitter Comets


Now it's time to make some comets. I place my comet pump sleeve on my aluminum ramming puck after making sure that the hose clamps are tightened. I place a funnel in the mouth of the sleeve and introduce a weighed amount of the glitter composition into the sleeve.

Then I put the comet pump ram into the sleeve, place the whole shebang on my 6x6x36 ramming post, and I whack the ram with 8-12 blows with my rawhide mallet. At a certain point, the comet will start to feel solidly consolidated.

It's just a matter of slightly loosening the hose clamps, and gently ejecting the comets from the pump sleeve with the ram. I then dry them for a couple of days in a well ventilated, warm area, or overnight in my drying chamber.


Ramming a Glitter Comet

One of the things I want to record is how much composition it takes to form different length comets with the 3/4-inch and the 1-inch pumps. Those results are as follows for both formulae:

1-inch comets
0.4 ounce	1/2-inch long
0.5 ounce	5/8-inch long
0.6 ounce	3/4-inch long
0.7 ounce	1-inch long

3/4-inch comets
0.2 ounce	7/16-inch long
0.3 ounce	5/8-inch long
0.35 ounce	3/4-inch long
0.4 ounce	13/16-inch long

3/4-inch and 1-inch Diameter Comets of Various Lengths

For stand alone comets, I'll press them as long as they are in diameter. For rising shell tails, I'll press them long enough so that they burn out just as the shell breaks (duration of shell timing fuse). I'll be determining the burn time of each length comet in a minute.



Priming the Comets


Many folks would say that these comets do not need any priming because they are mostly made of BP meal, which ignites very well all on its own.

But, often pumped stars and comets have a very smooth surface, and I've learned the hard way to avoid assuming they'll light without priming. They might, and they might not. So I prime everything.



Scratch Mix BP Prime Formula

Component	Percentage	Ounces
Potassium nitrate	0.75	7.5 ounces
Airfloat charcoal	0.15	1.5 ounces
Sulfur	0.10	1 ounce
Dextrin	+0.05	0.5 ounce
Total batch weight:		10.5 ounces

I screen the potassium nitrate through the 100 mesh screen, and then screen all the chemicals together through the 100 mesh screen twice to thoroughly incorporate them. Then I put them into a plastic tub, with a lid, and shake them a bit to really mix them well.

Depending on how many comets I plan on priming, I'll take a few tablespoons-full of the dry prime comp, put it in a paper cup, and add enough water to make a thick syrup, like honey. After stirring this a bit with a wooden stick, I use a brush to coat one end of each comet. Then I dunk that end into some FFg sporting grade black powder, or some more of the homemade black powder meal. What I want is a rough, granular surface that will more easily take fire.

I allow the primed comets to dry overnight outdoors, or for a couple of hours in the drying box.


Priming Glitter Comets



Installing the Comets on an Aerial Shell or Rocket Header


It is easy to hot-glue one of these comets onto a plastic or paper shell or header. Just put a healthy blob of the glue onto the bottom of the comet, and press it onto the device. Then apply more glue which laps up onto the side of the comet, and helps hold it in place during lift.

A more traditional way of installing rising tails on paper ball shells is to wrap the comet with a couple of turns of thin pasted kraft paper or moistened gummed tape. Have half of the strip lap onto the side of the comet, and half hanging off the bottom of it. Slice the overhang paper with scissors about every half inch and fold out the tabs. Apply Elmer's or wood glue to the bottom of the comet and to the tabs, and press in place on the top of the shell.

I like to cover the shell's rising tail with a disc of tissue paper, tied on with a bit of string. This dresses the shell up, and keeps the comet's prime layer from rubbing against anything during transport. These comet tails will ignite when the shell's lift gasses flow around them before the shell leaves the mortar.


Attaching Comet to a Aerial Shell for Rising Tail Effect



Test Firing the Two Different Gold Glitter Comets


To test fire the 3/4-inch and 1-inch comets made with the two different formulae, I shot them out of a star gun which has 7/8-inch and 1-1/8-inch tubes. I also tested some of the 1-inch comets out of a small paper mortar made with base #PL3002 and tube #TU2123.


Mortar and Star Gun Used to Test-Fire Glitter Comets

Using commercial FFFg black powder, I had to use a flat 1/4 teaspoonful for the 3/4-inch comets, and a flat 1/2 teaspoonful for the one inchers.

With my homemade red-gum granulated BP, I had to use a heaping 1/4 teaspoonful, and a heaping 1/2 teaspoonful respectively.

I installed 3-inches of visco fuse, the BP lift powder, and then dropped the comets in. If I was making these babies for a display, and they were going to be boxed and transported, I'd use a layer of tissue paper between the comet and the BP, and a layer of tissue pressed in above the comet to hold everything in place until firing.



Test Results


Both of the formulae resulted in beautiful comets, and the one-inchers would make a very nice addition to any display. I have to say I like the Gold Twinkler a bit better than the D1. The GT creates very golden, long hanging, large glitter, whereas the D1's glitter is a bit more pale, and does not hang quite as long.

But either one is very beautiful, and the economics of the D1 formula make it quite attractive to produce.

In order to have a rising tail on a shell that lasts as long as the shell's ascent before burst, I measured the burn times of various lengths of comets with the star gun and a stopwatch. I wrapped the comets with aluminum foil duct tape to simulate the amount of the comet surface that would be exposed and burning if it was attached to a shell.


Foil-Tape-Wrapped Comet Ready to be Fired and Timed

The burn times were as follows, along with the size of the shell to use them on:

1/2-inch long	2.5 to 3 seconds	3-inch to 6-inch shells
5/8-inch long	4.3 seconds	8-inch to 10-inch shells
3/4-inch long	4.5 seconds	8-inch to 10-inch shells
1-inch long	5 seconds.	10-inch shells

For tails on 12-inch shells, I'd use 1.25-inch to 1.5-inch long comets.

Shell rising comet tails can vary from 3/4-inch to 2.5-inch in diameter or larger, depending on the size of the shell.



Conclusion


The one thing I'd add about these beautiful gold glitter comets is that my wife, Molly, who is not passionate about fireworks--especially really loud ones--has always loved gold glitter effects. That's reason enough for me to use a lot of gold glitter in my fireworking.



Bonus Round


It is easy to make a brilliant Silver Titanium Spark comet using the methods described above.

Component	Percentage	Ounces
Black powder meal	0.68	5 ounces
Spherical titanium	0.27	2 ounces
Dextrin	0.05	0.4 ounces
Total batch weight:		7.4 ounces

Fine Ti will give a short, bushy tail. Coarse Ti will produce a longer tail filled with larger sparks.

These titanium comets produce an effect which contrasts nicely with the glitter ones.

Stay Green,

Ned
ngorski@skylighter.com



15% OFF EVERYTHING AT SKYLIGHTER!
Order at least $177.77 worth of anything from Skylighter, and get 15% off everything on the order. This sale starts now and ends midnight, Friday, August 29th, 2008.

The Fourth of July has come and gone, so now is the time to get started on your next fireworks projects. If you have been following Ned Gorski's weekly projects, you already know that some of his projects take time and you may need a lot of items that you don't already have in your kitbag.

Whatever you need--books, videos, chemicals, tools, or anything else--use this sale to save yourself a bunch.

Early Bird Special. Order before midnight Monday, August 25, 2008 and get one really, really ugly star gun worth $48.24 free.



We only have 30 of these ugly star guns. They were made by an incredibly angry Chinaman whose wife had left him for a young star roller at the Won Hong Lo Fireworks Company. As she was walking out the door, she stood with her hands on her hips and said, "I hate you. You don't know notheeng about quarity control."

We have to agree. But we don't know what happened to him after he made the 30 star guns we have in stock. So I am not sure if we will ever get these ugly guns again. That automatically makes them collectors' items.

And you can get your's fer free, by jumping right now. And they only go to the first people who order, so I cannot guarantee that you will get one.

So don't miss this chance to get anything you want from Skylighter for 15% off, and pick up a free star gun worth $48.24 just for placing your order by midnight this coming Monday.

To get 15% off and a Early-Bird Bonus click here.

Note: You must enter the promo code during checkout. If you take advantage of the early bird special, you will not see the free star gun in your shopping cart (because it's far too ugly). We will add your freebie once we receive your order. Also, shipping costs will be higher than what you see in your shopping cart, because the weight of the free star gun will not have been calculated there. Skylighter can not guarantee your star-gun will be as ugly as the one in the picture.



VISIT OUR NEWSLETTER ARCHIVE
Our newsletter archive contains every article, including every fireworks-making tip, trick, and technique that we have revealed to our subscribers since June of 1999.

Now obviously, our more recent articles contain our latest news, but this wealth of fireworks know-how is still highly recommended reading. You’ll find lots of step-by-step instructions for making all kinds of fireworks including stars, dragon eggs, comets, spin stabilized rockets, strobe rockets, whistle rockets, black powder rockets, aerial shells, fountains, Class C fireworks displays, volcanoes, smokes, fuses, electric matches, tourbillions, saxons, special effects fireballs, colored liquid fire, colored fireballs, mines, and much, much more.

[aljufri]

MAKING & TESTING HIGH-POWERED BLACK POWDER

By Peter Gilbert


Black powder (BP) is an almost ridiculously simple pyro ingredient. Mostly just three chemicals, blended together in simple ways, but producing wonderful results. Black powder exemplifies for me the endless learning, experimentation, and creativity that fireworking holds for us. If so much fun can be had with BP, imagine what else fireworks-making has in store for you.



Introduction


In this article I'll be writing about two basic skills:

1. How to make black powder using 4 basic methods, ranging from the use of only two simple screens, through the use of a star-roller, hydraulic press, and/or a ball-mill.
2. How to test various black powders to compare their power, and to determine how much to use when lifting a typical fireworks aerial shell.

I hope this article will be useful for both the novice fireworker, and for the most experienced one.



What is Black Powder (BP)?


Have you ever taken the covering off of the bottom of an aerial shell and observed the black granules which are used as the shell's "lift powder?"


Black Powder Used As Shell Lift Powder

Black powder is perhaps the most basic and useful of all fireworks ingredients. It is used to lift shells, comets, mines, Roman candle stars, and as a base-composition in some rockets and many other fireworks components and devices.

Here is the definition of black powder taken straight out of the The Illustrated Dictionary of Pyrotechnics (Skylighter #BK0043):


"Black powder - An intimate mixture of finely powdered potassium nitrate (75%), charcoal (15%), and sulfur (10%). Commercial black powder may be granular or finely powdered. It serves as a propellant and has a wide variety of uses. Black powder should not be confused with smokeless powder, which is not a suitable substitute for black powder (in fireworks)."


So, What is "High-Quality" Black Powder?


For the sake of this article, at least, let's define high-quality BP as that black powder which will adequately serve the needs of the fireworker, and which comes close to, or exceeds, the quality and explosive power of commercially available black powder. Goex brand is a well-known, and often referred to, example of commercial powder.


Goex Brand Black Powder



Well, Can’t I Just Buy the Black Powder I Need?


First of all, didn't we say, "Hey, I'd like to learn how to make fireworks"?

You can buy some types of black powder. There are two types available, sporting and blasting. The sporting grades of BP, made by Goex and others, are readily available from some gun and sporting goods shops, and some online sources. These are the "Fg, FFg, FFFg, FFFFg, " etc. grades listed in the black powder grain size charts.

The blasting grade, "A" powders are most frequently used in fireworks. 2FA, 4FA, and Meal-D are the sizes we need the most. (See the article on black powder sizes and grades Size Does Matter in Skylighter Fireworks Tips #44.) They are available only to holders of a BATFE explosives license.

If you can find BP at your local gun shop, it usually retails for $16 - $24 per pound. Beginner shell makers can easily use more than 50 pounds of 2FA per year. That's about $1,200 at retail! It doesn't take long, buying commercial BP, before you start asking yourself, "Self, ain't there a less expensive way?"

Even if one has the BATFE license to buy commercial 2FA in bulk (50 or 100 lbs at a time), the current price of it is $7-8 per pound.

So, economics, practicality, availability, and the pride of actual fireworks-making, all eventually make it inevitable that most pyro-hobbyists will make their own BP. And the good news is that it is Federally legal to make it yourself, without an ATF license. But, check your state and local laws first to make sure you can comply with them as well.

Many would argue that the very first, important step to learning the art of fireworking is tackling the skill of making high-quality black powder.



What Affects the Quality of Homemade Black Powder?


Typically, these are the key variables in making powerful, high-quality BP:

#1: The quality of the chemicals and the type of charcoal (wood species) that is used. Willow charcoal is often being referred to as the wood of choice for BP charcoal. I use spruce/pine as the wood that I turn into homemade charcoal. (This subject is discussed in the Making Charcoal article, Skylighter Fireworks Tips #90.) I'll be comparing BP made with this pine charcoal, with that made with commercial airfloat charcoal.

#2: The method used to pulverize and intimately mix the ingredients. Screening through a fine-mesh screen or ball-milling can be employed. (This subject is thoroughly explored in Ball Milling 101, Skylighter Fireworks Tips #91.)

#3: How the mixed ingredients are consolidated and granulated.

#4: The size of the granules, especially with BP that is made into pucks that are broken up (corned).



Four Methods of Making Black Powder


I have played with several methods of making BP. Now I'm going to make black powder in four of those ways:

- Pressing BP pucks and breaking them up.

- Coating the BP onto rice hulls.

- Ball-milling the composition, wetting the BP with red-gum and alcohol, and granulating it through a 4 mesh screen.

- Simple screening of the chemicals through a 100 mesh screen, and using the red-gum/alcohol granulation method.



First Step


I ball mill four 20-ounce batches of mill-dust BP, two batches using pine charcoal, two more using commercial airfloat. Each batch has 15 ounces of potassium nitrate, 3 ounces of charcoal, and 2 ounces of sulfur. I run the ball mill for 2 hours for each batch. I end up with 40 ounces of pine charcoal mill-dust, and 40 ounces of commercial charcoal mill-dust.

(Mill-dust is the term that is used for BP as it comes straight out of the ball mill, before any granulation.)



Second Step


I take 16 ounces of the pine charcoal mill-dust, add 1.6 ounces of water (10%) to it, and thoroughly incorporate the water into the powder with my gloved hands. Then I further incorporate the water with a screen colander. I press 1/8" thick pucks with that powder. I have found that if I apply about 1600 psi of pressure on the pucks when I press them, that they are as solidly consolidated as they are going to get. I put the finished pucks into the drying chamber to dry.

I do the same with 16 ounces of the commercial charcoal mill-dust.

(I have found that it is quite easy to break the pucks up a bit by hand while they are still damp. This makes it easier to granulate them later on.)


Black Powder Pucks, Pressed and Crumbled






Third Step I take 16 ounces of the dry pine charcoal mill-dust, add 0.8 ounce of dextrin (+5%) to it, screen it to thoroughly incorporate it, and coat that BP onto 2.4 ounces of rice hulls in the star roller (7/1 ratio of BP to rice hulls). (See the Nice Shells in 2-1/2 Days, Part 2 article in Skylighter Fireworks Tips #92.) I put the coated hulls on screens and into the dryer. Although puffed rice cereal can be used in this process, rice hulls make more durable grains.

I repeat the process with 16 ounces of the commercial charcoal mill-dust.


Plain and Black Powder Coated Rice Hulls



Fourth Step


I take 8 ounces of the dry pine charcoal mill-dust, and dampen it with 1/3 cup of denatured alcohol (from Home Depot) which has 1/10 ounce of red-gum (about 1% of the mill-dust weight) dissolved in it. I slowly add enough additional alcohol to the mill dust, only as much as necessary, to end up with a nice, putty-like "dough ball." Then I granulate that dough-ball through a 1/4" (4 mesh) screen onto a kraft-paper lined tray for drying.


Black Powder with Red Gum and Alcohol, Granulated

I repeat the process using commercial charcoal mill-dust.

Warning: Working with alcohol or any other solvent that puts a lot of fumes into the air, I do so outdoors so fumes cannot collect and be ignited, and I wear a mask-respirator to avoid breathing the fumes.



Fifth Step


I simply take 15 oz. of potassium nitrate and screen it through a 100 mesh screen. If all of it won't pass the screen, I mill it a bit in a small coffee grinder until it will pass the screen.

Warning: I never mill anything but individual chemicals in the coffee grinder. I use one coffee grinder only for oxidizers, and a different one for fuels. I thoroughly clean it after using it for one chemical.

Then I combine that 15 oz. of potassium nitrate with 3 oz. of pine airfloat charcoal and 2 oz. of sulfur, and pass them twice through the 100 mesh screen to thoroughly mix them.

This 20 oz. batch of BP chemicals is then wet with about 3/4 cup of the denatured alcohol which has 0.2 oz. of red-gum dissolved in it. More alcohol is added as needed and the putty is granulated as in Step 4 above.

I do the same for a similar batch using the commercial airfloat charcoal.

Many of you are now saying, "Aw, he's never gonna get a useful BP with that simple screening method. It has to be ball-milled." You just wait.

All of the powders produced above are left in the drying chamber until they are completely dry. (Skylighter Fireworks Tips #92 shows you how to make and use a drying chamber.)



Granulating and Sizing the Black Powders


Once the powders have dried in the drying chamber for a day or two, I process them in various ways.

Processing black powder pucks (see how to granulate black powder pucks in Fireworks Tips #93.)

With the pine charcoal pucks, I end up with 10.7 ounces of the 2FA, and 1.75 ounces of the 3FA. (In reality, commercial 2FA powder contains grains from 4 to 12 mesh, but my 2FA consists of only the coarser grains.)

With the commercial charcoal pucks, I ended up with 10.15 oz. of 2FA powder, and 2.05 ounces of 3FA.

Note: I don't really like the process of pressing all these pucks, and then crushing and granulating them. It's a painstaking, time consuming, and messy process. On the other hand, it is nice to end up with such hard, durable grains, which are practically indistinguishable from commercial black powders.


Processing black powder coated rice hulls
After dumping the BP coated rice hulls from the drying screens into a rectangular tub, I then simply screened them on my 12 mesh screen to sift out the fine BP grains and dust. There was not a whole lot of that, but I wanted to end up with just the coated hulls.


Processing red-gum black powder
With the red gum/alcohol granulated powders, I dumped them from the drying screens and forced them through my 4 mesh screen to break up the larger clumps. Then I screened that powder on my 12 mesh screen to remove the fines and dust, ending up with nice, hard grains in the 4-12 mesh size.


Black Powder with Red-Gum and Alcohol, Granulated



Some Observations


Coating the rice hulls and processing the resulting grains is relatively easy, and the alcohol/red gum granulated powder is probably the easiest to produce. It is a bit more expensive to make, though, since the red gum and alcohol cost a little more than dextrin and plain water.



Results


So, now I have my 10 homemade powders to compare with each other. I also have some German Wano 2FA powder (equivalent to Goex 2FA) which I screen and separate into 4-8 mesh and 8-12 mesh powders, as I did with the homemade powder made from pucks.

• Pine charcoal 2FA
• Commercial charcoal 2FA
• Pine charcoal 3FA
• Commercial charcoal 3FA
• Pine charcoal BP coated rice hulls
• Commercial charcoal BP coated rice hulls
• Pine charcoal, ball-milled BP, processed with alcohol and red-gum
• Commercial charcoal, ball-milled BP, processed with alcohol and red-gum
• Pine charcoal, simply screened BP, processed with alcohol and red-gum
• Commercial charcoal, simply screened BP, processed with alcohol and red-gum
• Wano 2FA
• Wano 3FA

Now I'd like to test these 12 BP's and compare their relative performances.



The Big Experiment


So far, all of this is very interesting information, but, quantitatively, it does not tell me a whole lot that is useful for me in making fireworks.

I have some big questions I'd like answers to:

• To what extent does the type of charcoal affect the power of the BP?
• Consolidated and granulated using 4 different methods, how much variation in the BP's power will result?
• How do these homemade BP's compare in power with commercially produced powders? How can this be tested and quantified?
• How much should I use of one of these BP's to lift an aerial shell?
• How do the various methods of production compare as far as expense and labor? Are some methods significantly easier than others for the manufacture of BP?

I have to admit that the process I'm about to describe is where my creative juices really start flowing in this hobby. Being curious about something, thinking about it, doing some experimenting, pondering the results, and coming to some conclusions that are useful in my future activities--that's what this is all about for me.

We have quite a few variables in the above information when it comes to choosing how to make powerful BP and how to use it in our pyro projects.

I want to design an experiment to compare black powders which incorporate these different variables, in order to know how each of those variables affects the BP's power, and to be able to determine which materials and techniques are preferable when making my BP.

I have my 12 different types of black powder sitting in front of me. Now I'll test them in various amounts, lifting dummy shells, to compare their relative performances, and to find out exactly how much of each of them to use when lifting an actual fireworks shell.



Testing the Black Powders.


In years past there has been a "game," played at the Pyrotechnics Guild International's annual convention, called "pyro-golf." Folks brought samples of their prize black powders, and a fixed amount of each was used in a mortar to shoot golf balls into the air. The flights were timed, and the longest flight time would be declared the First Prize black powder. This is a good method for comparing the power of different powders.

Homemade powders could also be compared to commercial BP's at the same time. Usually the homemade powders outperformed the commercial ones by quite a sizable margin.

There are other ways to compare black powder performances, but I like the golf ball test because it duplicates the real-life application of using black powder to lift aerial shells.

For testing my 12 BP's, I'm going to use my version: "Pyro-Baseball." With "Pyro-Baseball," I use baseballs and a 3" mortar to simulate the lifting of 3" spherical fireworks shells. Baseballs are just the right size and weight. They save me the time, expense, and hassle of having to build actual dummy shells.

For my tests, I'm using a one-piece, HDPE (high-density polyethylene) "gun." Whichever gun you use, it is a good idea to use the same mortar for all of the comparison shots. This will minimize variations from one test to another.

On page 140 of The Best of AFN II (BAFN II) are some charts showing recommended BP lift amounts for various types and sizes of shells. Table 1 indicates that, for lifting a 3" ball shell, 0.6 oz. of FFg, or 0.75 oz. of 2FA would be appropriate amounts of commercial lift powder.

And, on Page 17 of the PGI's Display Fireworks Operator Certification Study Guide, one can find a nifty table that shows the typical (desired) heights that various size fireworks shells ascend to before bursting. This table shows that a 3" fireworks shell would rise to about 300 feet and then burst.

That's good information to have. Using about 0.6 to 0.75 ounces of my Wano BP ought to send one of my baseballs up to about 300 feet. I can weigh that amount, drop it down into the bottom of a 3" mortar, insert 4" of visco into the fuse hole at the bottom, drop a baseball into the gun, and light 'er up.


3" Mortar Loaded and Ready for "Bear"

But, how do I know if the ball actually ascends to 300 feet before it peaks out (at apogee) and starts to descend? One simple physics equation is all that is necessary to figger that out. If you drop an object and time its descent to the ground, the distance the object has fallen, in feet, is given by the equation, Distance = 16 x time x time (16 x time squared), when the time is measured in seconds.

For example, if I fire my baseball, and start a stopwatch when its flight peaks out at apogee, and then stop the stopwatch when the ball hits the ground, I'll be able to read the time it took the ball to fall to the ground from that peak. Let's say that my stopwatch indicates a time-of-fall of 4.18 seconds.


Timing the Fall of a Dummy Shell

To see how high the baseball was when it started to fall (at apogee), all I have to do is multiply 16 x 4.18 x 4.18 and I get a height of 279.55 feet. That's pretty close to my desired 300 feet. So I know that using the amount of lift powder that I used, or maybe just a tad more, would be a good quantity of that BP to use in the future for this size and weight shell.

This is what I'll be attempting to determine with each of the 12 experimental powders. Once I know those amounts for each powder, I'll then be able to compare their relative powers with each other. I'll tabulate that info and have some very useful results and conclusions. Just what I was looking for to begin with.

Note: An interesting relationship that I've noted during past tests is the amount of time a dummy shell takes to rise to apogee after being fired from the mortar, compared to the time it takes to fall to the ground. I've noted that it takes a spherical dummy shell approximately half the time to rise to apogee that it takes the shell to fall to the ground from apogee.

Another way of saying this is that, of the total flight time from launch of the dummy shell from the gun to it hitting the ground, one third of the flight time is spent rising to apogee, and two thirds of the time is spent falling to the ground from the apogee.

So, if I use various amounts of a lift powder and time the baseball's flight from the apogee to the ground, adjusting the powder amounts as I go along, until that time of fall equals 4.33 seconds, then I'll know exactly how much of that powder to use again to duplicate that height. 300' = 16 x 4.33 x 4.33.

If I want a slightly higher flight for a shell, for example one with a long burning willow star shell, then I'd use a bit more powder.



Pyro-Baseball Testing of Black Powders


So, I go out to my shoot site with my lovely assistant and all my testing materials: BP's, scale, spoon, paper cups, notebook, pen, baseballs, mortars, visco, anvil-cutter (I never cut fuses with scissors, only with razor blade anvil-cutters), chairs, table, stopwatches, sunglasses, camera, re-bar, and duct tape.


My Lovely Assistant, Ready to Take the Field, and the Ammo

No, she didn't really try to catch the balls. She had to man (woman) one of the stopwatches instead.

The mortar was taped to a piece of rebar driven into the ground, angled away from us, and the ammunition was prepared. I had previously drilled a small fuse hole near the bottom of the mortar.

I had prepared some charts in advance to take notes for each powder test. The vertical axis represents the time of fall in seconds, and the horizontal axis represents ounces of black powder in 0.05 ounce increments. I drew a horizontal line at 4.33 seconds since that time of fall represents a height of 300 ft., which is what I'm shootin' for.


One of My Hand-Plotted Graphs

Then, it was just a matter of starting to fire baseballs with measured amounts of one of the experimental BP's, such as the one in the above chart: ball-milled, commercial charcoal, alcohol/red-gum granulated. We used two stopwatches, recording the total time of flight, and the time of fall from the apogee to the ground.

Judging the exact apex of the flight can be a bit tricky, since there is a second before the apogee where the flight up really slows down, and there is also a bit of time after the apogee before the ball really starts to pick up speed. But, we just did the best we could. It's probably a bit more accurate to use a time that is 2/3 of the total flight time, from lift to landing.


Baseballs After Being Fired From the Mortar

Warning: After each baseball firing, there may be hot sparks remaining in the mortar. I am careful to wait a bit before reloading. Then I insert the visco fuse, drop the next portion of BP in, and then carefully drop the baseball in. I avoid getting any body part over the mouth of the gun when doing this, regardless of whether I know the fuse is lit. A baseball fired at this speed could easily kill a person or remove a hand or arm.

I wanted to start with a small amount of the powder, gradually increasing it until I started to get flights that were a bit too high. I figured that would give me the spread of data which I could use to determine the right amount of powder for a 300’ high flight. The following is a listing of the amounts of this one particular powder that I used, and the resulting flight times that we recorded.

Ball milled, commercial charcoal, red-gum/alcohol granulation

Amount of BP	Time from apogee to ground	Total flight time
0.25 oz.	2.06 seconds	3.28 seconds
0.40 oz.	3.50 seconds	5.69 seconds
0.50 oz.	4.56 seconds	7.22 seconds
0.45 oz.	4.18 seconds	6.62 seconds

Below is a computer-generated graph of the data above.


Ball-Milled, Commercial Charcoal BP, Red-Gum/Alcohol Granulation

When these coordinates were entered into the graph, a couple of things became obvious. There is a linear relationship between the amount of lift powder that is used, and the corresponding flight time.

This graphed line, if extended down to the bottom of the chart, points to an amount of BP which would not even get the ball out of the gun, about 0.05 ounce in this case.

That graphed line crosses the 4.33 seconds/300' line, between 0.45 and 0.5 ounces of the BP.

Indeed, when the average time from apogee to the ground, is divided by the average total flight-time, the time from apogee to ground is about 2/3 of the total flight time from lift to landing.

With this powder, I'd use 0.5 oz. to reliably lift a 3" ball to 300'.

We did this with each powder, firing baseballs about 40 times into the air.



Results


Repeating the tests described above with each of the 12 BP's, I was able to determine the optimum amount of each powder for lifting a baseball to 300'.

0.30 oz.	Milled pine charcoal, red gum/alcohol
0.35 oz.	Milled pine charcoal, pucks sized to 3FA
0.40 oz.	Milled pine charcoal, coated on rice hulls
0.45 oz.	Milled commercial charcoal, pucks sized to 3FA
0.50 oz.	Milled commercial charcoal, red-gum/alcohol or on rice hulls
0.55 oz.	Commercial Wano BP, 3FA
0.60 oz.	Commercial FFg recommendation from BAFN II chart
0.75 oz.	Commercial 2FA recommendation from BAFN II chart
0.75 oz.	Commercial Wano BP, 2FA
0.75 oz.	Milled commercial charcoal, pucks sized to 2FA
0.75 oz.	Milled pine charcoal, pucks sized to 2FA
0.75 oz.	Simply-screened, pine charcoal, red-gum/alcohol
0.90 oz.	Simply-screened, commercial airfloat charcoal, red-gum/alcohol

Note: It was almost difficult to use a small enough amount of the pine-charcoal/red-gum-alcohol powder. A third of an ounce is a mighty small amount of lift powder.



Answers


To what extent does the type of charcoal affect the quality of the resulting black powder? Homemade pine charcoal produced powder that was marginally better than that produced with the commercial charcoal, but both can produce BP’s that far outperform commercial black powders.

How did the 4 methods of processing/granulating the BP's compare when the resulting powders were tested? All three methods that employed ball-milling produced powders that were very comparable. The method that used simply-screened chemicals produced BP that, while not as powerful, was very functional in amounts comparable to commercial 2FA.

How does the size of the granulation of pressed pucks affect performance? For these 3" dummy shells, the finer 3FA (8-12 mesh) granulation far outperformed the coarser 2FA (4-8 mesh) granulation.

How much lift powder should I use for a shell? The amounts in the chart above indicate how much of each type of powder to use for a 3" ball shell. These amounts can be dialed in when manufacturing actual fireworks shells. In general, if I were to multiply the recommended amount of lift powder listed in the BAFN II table by 0.6 for the milled, pine charcoal BP's, or by .75 for the milled, commercial charcoal BP's, I'd arrive at a good starting amount of homemade lift powder.

How do the 3 methods of processing/granulating the homemade powders compare as far as difficulty and expense? The easiest powder to make is the screened red-gum/alcohol granulated BP, followed closely by the milled red-gum/alcohol BP, and then the BP on rice hulls. Pressing pucks and corning them is significantly more difficult and messy.

The red gum and alcohol make that method slightly more expensive in material cost than the other two methods. Milling requires an up front investment in a machine and milling media. Rice hulls are cheap, so using them does not make that method much more expensive than pressing the pucks. All of the methods of making homemade BP are much less expensive than purchasing commercial black powder.



Final Conclusion


For my purposes, either homemade or commercial charcoal produces completely satisfactory powder. I really like the ease of production, and the final resulting powder when the red-gum/alcohol method is employed to make BP, so I'll probably use that method when making lift powder for aerial fireworks shells.

To me, the simply-screened, red-gum/alcohol method looks like the method-of-choice for simple, field-expedient, very functional black powder, and it can be produced without any complex or expensive machinery. This method is ideal for the beginning fireworker.

I think I'll bring my bucket of baseballs and a couple of 3" mortars to the next PGI convention, and whoever is interested can take to the field with me to go head-to-head with our prize black powders. May the best pyro win!

[gilbert]

Cutting, Treating, & Making Your Own Paper Tubes

By Peter Gilbert


Introduction

In some upcoming Fireworks Tips articles, I'll be discussing fountains (gerbs), wheel drivers, line rockets and black powder rockets.

These projects will require parallel wound paper fireworks tubes. To understand the difference between parallel and spiral wound fireworks tubes click here to read the heading above the tube section on the Skylighter website.

There are lots of different diameter and length tubes listed in that section. Why would we need to know how to cut and treat those tubes?

If you look at product number TU1065, you'll see a typical one-pound, 3/4-inch ID, 1/4-inch wall tube that is 30-inches long. Those tubes currently cost $54.59 for 25 of them, or $2.18 each. Four 7-1/2-inch tubes can be cut out of each of them, and each of those typical length rocket tubes would end up costing you $0.55 each.

Now, if you look at product number TU1068, you'll see those same tubes, but 7-1/2-inches long, selling for $40.71 for 50 of them, or $0.81 each.


TU1068 and TU1065 One Pound, 3/4-Inch ID Fireworks Tubes

That's a pretty big difference. If we know how to cut our own tubes out of the 30-inch long ones, we can save some money.

Additionally, some devices like short-duration fountains, stinger rockets, and other types of rockets require tubes of lengths that are different than 7-1/2 inches. Knowing how to accurately cut various lengths of tubes will be necessary when making those items.

Also, if these tubes are treated with a hardener, they will have a higher burst strength and will be more resistant to the flame burning through the tube side-wall while the device is functioning. So, it's nice to know how to treat the tubes to accomplish this.



Cutting Fireworks Tubes


You might be saying, "Ned, why don't you just use a hacksaw or coping saw to cut the tubes by eyeballing the crosscut?"

I have two main goals when cutting tubes: I want a very square cut which runs at exactly 90 degrees across the tube, and I want a straight, smooth cut.

I have used a, power miter, wood working saw to cut many tubes. This is a quick way to accomplish those goals. But it has some disadvantages. I don't use such power tools in my fireworking shop, so to use that tool I have to go to the shop where it is located. It is also a bulky, heavy tool, which is not conducive to taking to pyro events where I might be cutting tubes and making various devices. Power tools are also dangerous, and can "grab" tubes when they are being cut unless one is very careful.

In the past year or so I've settled on a tube-cutting method which accomplishes my goals but which does not have the disadvantages I've listed above.

I found a plastic, Stanley, hand-sawing miter box at Home Depot, which has black plastic cams for locking a work-piece in place during sawing. Unless I'm just making one quick cut, I screw the miter box to my workbench to hold it securely in place during cuts.


Stanley Miter Box with Locking Cams

I also found a nice, sharp, clean-cutting pull-saw at the same store. This saw cuts the tubes easily, quickly, and with very straight, smooth cuts.


Marples Pull Saw


Cutting a Tube, Held in Place with Cams, Using the Miter Box and Pull-Saw

Once the miter box is screwed down to my workbench, and the tube is locked in place with the cams, all it takes is smooth, gentle, pulling strokes on the saw to produce a nice, quick cut.

I like to cut about 1/4 inch off of the end of one of the long tubes so that I'm starting with a nice, square end, and then I'll start measuring and cutting my tubes.


End of a Freshly Square-Cut Tube

One of the really interesting things in pyro circles is how many different ways folks have to "skin the cat." There are quite a few variations that folks employ to cut their tubes, and many of them work well. This is just one way that I've found which produces the kinds of results that I'm looking for.



Treating Tubes


For many devices, treating the tubes to increase burst strength and decrease side-wall burn-through is not necessary. For others, this process can really increase the performance of the tubes.

The most well-known product for treating paper tubes is Minwax Wood Hardener, available at Home Depot and other hardware and paint stores.


Minwax Wood Hardener for Treating Paper Tubes

Warning: This stuff contains some pretty nasty ingredients. The solvent evaporates very quickly, putting highly toxic and flammable vapors into the air. Read the warning label, and only use it outdoors in a well ventilated area. Seriously!

I use two methods to soak the tubes in the wood hardener. If I'm only treating a few tubes, I'll put them in a plastic, Ziploc freezer bag, and pour the hardener into the bag until the tubes are submerged. Then I'll zip that bag closed while expelling most of the air. I'll then put that closed bag into another one and zip it closed as well.

I like to soak the tubes for 15-30 minutes, and I'll tumble the bag occasionally to make sure all of the tubes' surfaces are being soaked.


Paper Tubes in Plastic Bags, Soaking in Wood Hardener

Once the tubes have soaked for the allotted time, I'll open the baggies and pour the excess hardener back into the cans using a funnel.

An alternative that I'll use if I'm treating quite a few tubes is to put the tubes into a one-gallon paint can that is about half full of the hardener. I'll insert as many tubes as I can, and then top the can off with the hardener. Occasionally I'll pull the tubes out one at a time and rotate them so that both ends get evenly treated.

While the tubes are soaking, I cover the can with a plastic bag to minimize evaporation.


Soaking Tubes in a Gallon Paint Can Filled With Wood Hardener

Then, with either method, I'll remove the treated tubes and stand them on end on waxed paper to dry, once again in a well-ventilated outdoor area. The tubes can take 1-3 days to dry completely, depending on the climatic conditions.

The way I tell if they are completely dry is to put a few of them into a plastic bag and seal it. Then I'll open the bag in an hour or so and see if I can smell any more of the evaporating hardener solvent. I'll allow the tubes to dry until I can no longer smell it.


Drying Treated Paper Tubes on Waxed Paper



Testing the Treated Tubes


There is a nifty way to tell if the treatment is actually increasing the tubes' burst strength. I'll cut some 2-inch long sections of both treated and untreated tubes, and close off one end of each tube with masking tape.

Then I introduce 20 grams (0.7 ounce) of powdered clay, either bentonite or hawthorne-bond-fireclay, into the tubes.

Using a flat rammer, my rocket press, and a pressure gauge, I'll slowly increase the pressure on the clay in the tube until the tube splits. I'll make a note of the pressure at which the tube fails, and repeat the test several times to insure that the results are reliable.


Testing the Burst Strength of Paper Tubes

Performing this test with treated and untreated one-pound, 3/4-inch ID, 1/4-inch wall, Skylighter tubes, I got the following results:

Untreated tubes failed at	4550 psi on the clay
Treated tubes failed at	5450 psi on the clay

That is an improvement of about 20% in the burst strength of the tubes.

Skylighter has also started to stock high-quality tubes in the 3/4-inch ID, 1/8-inch wall size.

I tested these tubes as well:

Untreated High Quality tubes failed at	6800 psi on the clay
Treated High Quality tubes failed at	6800 psi on the clay

Rolling Handmade Tubes


"But can't we make our own tubes?"

I have made some homemade tubes, with some success, but in the end I think it's hard to beat store-bought ones.

If I had to roll my own though, I'd use one particular method that a well-known rocket expert, Terry McCreary, has popularized.

This method uses a metal former (mandrel) around which a release paper is wound, followed by rolled on layers of polyethylene-coated kraft paper. This paper is available at http://www.centralpack.com (in Protective Wraps) and a 24-inch by 600-foot roll of it currently costs $27.08 plus shipping. The paper is also available in 18, 36 and 48-inch widths.

This 600-foot long roll would make over one hundred and thirty 3/4-inch ID tubes, 1/8-inch wall, and 18 inches long. You can see that this results in some pretty inexpensive tubes, if you don't count the cost of your labor.

For the mandrel which will form the tube, I purchased a 3/4-inch OD, 1/16-inch wall, steel tube, 36 inches long, at Home Depot in the nuts-and-bolts aisle. I cut the tube in half with a plumbing tubing cutter and filed the ends smooth. This produced two 18-inch formers. A hacksaw could also be used to cut the tube.


Steel Tube Formers on Which to Roll Paper Tubes

The release paper is parchment paper which is used for baking, and is available in grocery stores. I tear off a 20-inch long piece of it for each former and then I wrap the paper around the formers.

It is important to get the paper wound on the mandrels very tightly to eliminate any loose or weak spots in the final tube. It helps to roll the paper-wrapped-tube on a flat, hard surface, pressing down with the palms of your hands, until the paper is tightly wound onto it.


Parchment Paper Tightly Wrapped on Steel Tube

For each tube, I cut three 18-inch long pieces of poly-kraft paper off my 24-inch roll. I cut these using a large framing square and a razor knife to get very straight, square cuts.

Then I roll these three pieces on the tube former over the parchment paper, poly-coated side in, which results in a total of 72 inches of kraft paper rolled on. The resulting wall thickness is 1/8 inch, and the final tube OD is just a little over one inch. Once again I roll each piece of paper on very snugly.


Poly-Kraft Paper Rolled onto Former, Over Parchment Paper

The edge of the kraft paper is secured down with 3-inch lengths of 2-inch wide, clear packing tape.

Then the tubes are put in a 275 degree oven for an hour. This melts the polyethylene coating on the kraft paper and glues each lamination to the next one, resulting in a solidly glued-together tube.


Cooking the Tubes in a 275 Degree Oven for One Hour

The tubes are then removed from the oven and allowed to cool for several hours until they reach room temperature. The steel mandrels are then pushed out of the center of the tubes with a 1/2-inch diameter wood dowel, and the parchment paper is unwound and removed from the inside of the kraft tubes.

These 1/8-inch wall, handmade tubes were tested and have a burst strength of 4100 psi on the clay.



Conclusions


I have a simple, accurate method of cutting tubes to the lengths that I need.

Treating the standard tubes increases the burst strength by 20%.

Untreated high quality tubes have a 50% higher burst strength than untreated standard tubes.

Treating the high quality tubes does not increase burst strength in the tubes that I tested.

I have a method that I can use to make my own handmade tubes if I choose to.

There are some devices that would work fine with the untreated standard tubes, some that would work better with treated standard tubes, and others (like end-burning rocket and girandola motors) that will require the high quality tubes.

In forthcoming Fireworks Tips articles we'll be playing with some of those devices.

[gilbert]

Bubuk mesiu merupakan campuran bahan peledak yang terdiri dari sulfur, Karbon dan potassium nitrat (juga dikenal dengan nama garam peter "saltpetre/saltpeter") yang bisa terbakar dengan cepat, menghasilkan sejumlah padatan panas dan gas yang biasa dipakai sebagai bahan pembakar/propellant pada senjata api dan sebagai campuran petasan.



KOmposisi Bubuk Mesiu
- nitrat — biasanya potassium nitrate (KNO3)—akan mensuply oxygen untuk reaksi;
- arang, yang mneyediakan bahan bakar reaksi dalam bentuk karbon (C);
- belerang (Sulfur), bisa sebagai bahan pembakar, nyala dalam suhu rendah serta meningkatkan kecepatan pembakaran.

Persamaan kimianya adalahh:

2 KNO3 + S + 3 C → K2S + N2 + 3 CO2

persamaan berikut ini yang lebih akurat, tapi disederhanankan:

10 KNO3 + 3 S + 8 C → 2 K2CO3 + 3 K2SO4 + 6 CO2 + 5 N2.

[gilbert]

Nitrocellulose kalo diliat namanya, kayaknya ini bahan pangan, ada selulosanya. padahal ini adalah jenis bahan peledak.

Nitrocellulose sering disebut juga "Bubuk mesiu "/"gunpowder" atau "guncotton". Lebih stabil dibandingkan black powder, dan juga lebih banyak menghasilkan gas panas. Juga membakar lebih cepat dibandingkan black powder. Kenyatanya, nitrocellulose gampang banget dibuat, seperti cara berikut ini:

Kebutuhan Material:
Kapas (selulosa)
corong dan kertas saring
Asam nitrat
Kertas lakmus biru
Asam sulfat
air suling

Cara kerja
1. tuangkan 10 cc asam sulfat. tambahkan juga 10 cc asam nitrat.
2. segera tambahkan 0.5 grm kapas, dan biarkan selama 3 minutes.
3. angkat nitrocotton, dan pindahkan ke dalam beaker yang berisi air destilasi untuk dicuci didalamnya.
4. Biarkan material mengering, lalu bilas ulang.
5. setelah kapasnya netral ujilah dengan kertas lakmus biru, Notroselulose siap disimpan.

APA ITU RDX ?

Cyclotrimethylenetrinitramine, juga dikenal sebagai RDX, cyclonite, hexogen, dan T4, merupakan peledak nitroamine yang luas digunakan di bidang militer dan industri. dalam tatanama kita dikenal dengan nama cyclotrimethylene-trinitramine dan cyclotrimethylene trinitramine.

Dalam keadaan murni, RDX sintesis berwarna putih dan berbetuk kristal padat. penggunaannya biasanya digunakan sebagai campuran peledak.

RDX dalam berbagai komposisi bahan peledak kemiliteran.
KOmposisi A (wax-coated, granular explosive consisting of RDX and plasticizing wax),
KOmposisi A5 (dicampur dengan 1.5% asam stearat),
KOmposisi B (campuran RDX dan TNT),
KOmposisi C (palstik bahan peledak yang terdiri dari RDX, peledak jenis lain dan plasticizers),
KOmposisi D, HBX (Campuran RDX, TNT, aluminium bubuk, dan D-2 wax dengan kalsium kloride), H-6, dan C4.

daya ledak RDX pada kepadatan 1.76 g/cm³ adalah 8,750 meter per detik.

Bisa dibuat dengan mereaksikan asam nitrat dengan hexamine.
(CH2)6N4 + 4HNO3 → (CH2-N-NO2)3 + 3HCHO + NH4+ + NO3-
Senyawa ini akan terurai kira-kira 170 °C dan melebur pada 204 °C.



Rumus Kimianya : C3H6N6O6

Rumus strukturnya :
hexahydro-1,3,5-trinitro-1,3,5-triazine or (CH2-N-NO2)3.
atau
1,3,5-trinitroperhydro-1,3,5-triazine1,3,5-trinitro-1,3,5-triazacyclohexane (IUPAC name)

Pada temperatur ruang sangat stabil. hanya akan meledak jika dipicu oleh sebuah detonator, Kurang sensitif dibandingkan pentaerythritol tetranitrate (PETN). Walaubagaimanapun, RDX akan sangat sensitif ketika dikristalkan dibawah suhu −4 °C.

[gilbert]

Harga Bahan-bahan Petasan

CH5301 Potassium Nitrate, Chunky Style 5 lbs. (retail value $13.55)
CH8078 Clay, bentonite 5 lbs. (retail value $10.35 )
CH8168 Iron Oxide, Red 5 lbs. (retail value $22.55)
CH8216 PVC 5 lbs. (retail value $36.25)
CH8271 Sodium Benzoate 5 lbs. (retail value $21.70)
CH8249 Saran 5 lbs. (retail value $33.35)
CH8317 Teflon 5 lbs. (retail value $35.65)
CH8214 Polyethylene, Chlorinated 5 lbs. (retail value $25.30)
ZCH5420 Potassium Perchlorate, Italian 5 lbs. (retail value $34.05) (only 30 lbs. left in stock)
ZCH8318 Tin powder 1 lb. (retail value $17.30)
CH3049 Titanium flakes 1 lb. (retail value $15.85)
TU1013 Tube, parallel 3/8 ID x 2 in. long 100 ea. (retail value $13.50)
TU1020 Tube, parallel 3/8 ID x 2-1/2 in. long 100 ea. (retail value $14.30)
TU1019 Tube, parallel 3/8 ID x 3 in. long 100 ea. (retail value $14.75)
TU2126 Tube, spiral 1-3/16 ID x 4-1/2 long 50 ea. (retail value $15.30)

[gilbert]

Warning: the cutaway diagrams shown below are for educational purposes only. They should not be used as a guide for constructing your own fireworks. Never attempt to take apart fireworks.

AERIAL/CAKE

Repeating aerials are just as complex as aerial shells because that's basically what a repeater is - many tubes of mini-"shells" all in one unit. These clusters of tubes each have a clay plug in the bottom and a black powder lift charge. There are two holes in the side of each tube, and as the device is being constructed, small chunks of fuse are used to connect each tube to its neighbor. This way, when the first lift charge ignites and sends the effect into the air, the tube next to it ignites shortly afterwards, and so on. Most devices have several parallel-fused tubes towards the end of the "fire trail", so that several tubes ignite simultaneously (or in very rapid succession) at the end of the performance in order to intensify the display.

Repeaters contain smaller "effect tubes" that are usually about one-third to half the length of the main "launching tubes". Each of these has a construction very similar to a shell. When the lift charge in the launching tube fires, it ignites a time fuse and (usually) a colored star composition in the bottom of the effect tube. The star composition burns brightly as the tube rises, and at the at its maximum altitude, the burst charge ignites the effects. The diagram at the right shows stars, which would look like a small, uneven shell burst when ignited. But if you have ever lit off a repeater before, you would know that there are dozens of possible effects: effects tubes that go up and explode, ones that whistle, ones that crackle, ones that spin around on the way up, and even ones that give off parachutes. Next time you light a repeater, come back to that area the next morning and look at the ground around where you set it off - you will see dozens of these spent effects tubes (with nothing but the clay plug left).

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AERIAL SHELLS

Aerial shells are one of the most beautiful and certainly one of the most complex types of fireworks. A shell consists of main parts: a container, a lift charge, a time fuse, a burst charge, and stars/effects. The container, or shell casing, is a strong wall that protects the contents. The lift charge propels the shell out of the tube, and the time fuse ignites the burst charge at the right altitude. The burst charge then ignites the effects. Shells are launched from a tube known as a mortar. A string loop is often attached to consumer firework shells so it can lowered into the mortar by the fuse. When the fuse enters the shell, it ignites the burst charge, creating an explosion that ignites the time fuse and shoots the shell high into the air.

As the shell ascends, the time fuse burns towards the burst charge. At the precise altitude - usually where the shell is briefly hanging in the air - the time fuse ignites the black powder burst charge, causing the shell to explode. The powerful explosion blasts apart the shell casing and ignites the stars, scattering them in all directions across the sky. These stars burn brightly and give off sparks, creating a huge spherical pattern in the sky.

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DISPLAY TUBES

Repeating aerial tube devices are little more than several aerial shells fused together to go off in sequence, with a few seconds of delay between each shell. There are usually anywhere from 3 to 7 tubes which are glued down to a thick wooden base to stabilize the device. Each tube contains a typical aerial shell in the bottom, protected by a cardboard disk and a cap at the top of the tube. Holes are drilled in the bottom of each tube, and small chunks of fuse connect each shell to the tube adjacent to it. The tube on the end has a long fuse that runs outside for a few inches. When that fuse is lit, the first shell fires. The lift charge of that shell ignites the chunk of fuse leading into the next tube, which in turn ignites a shell about four seconds later, and so on.

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FIRECRACKERS

Firecrackers are the simplest and oldest of fireworks. A single firecracker is simply a paper tube of several layers to give it strength. It is plugged at both ends with a dry clay-like substance, and contains a small amount of flash powder in the middle. When the fire from the fuse ignites the flash powder, it creates a large volume of hot gas in a short period of time. The casing of the tube contains this gas until the pressure blasts the tube open with a loud "crack"

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FLYING SPINNERS (HELICOPTERS)

Flying spinners are another one of the most popular fireworks. It is little more than a ground spinner with a paper or plastic wing unit attached to the tube. When the propellant composition is ignited, it creates thrust which spins the device around. But whereas a ground spinner would simply bump around on the ground, the spinning motion of a flying spinner causes the angled wings to direct airflow downward, lifting the device into the air exactly like a helicopter (hence the name). Helicopters have a burst charge at the end of the propellant compound, which explodes at the end of the device's flight and ejects stars, ladyfingers, or a parachute.

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FOUNTAINS

Single tube fountains consist of a cardboard tube (which may be inside of a cone) that stands vertically on a plastic base. The tube is charged with a composition designed to make lots of sparks, flame, and gas. At the end of the tube there is a clay plug with a hole drilled into it, forming what is known as a "choke". Without a choke, the fountain would only give off a weak spray of sparks. With a choke, however, a lot of pressure builds up inside of the tube, which forces the gas and sparks out of the fountain with a much greater velocity. Very small fountain tubes (i.e., 1/4 in diameter) don't require chokes. The fountain composition is often layered as to produce different effects at different stages in the burning. For instance, one layer may burn to produce orange sparks, followed by a layer that produces white sparks and green star fragments.

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GROUND SPINNERS

Single tube ground spinners consist of a single tube (imagine that!) that is plugged at both ends with clay and is filled with a rapidly-burning composition. A small fuse hole has been drilled into the side of the tube, near one of the ends. When the fuse ignites the composition, hot gases are produced and rush out of the hole, propelling the device around its central axis. Because it is off-balance and doesn't have quite enough thrust to fly, the firework spins wildly and randomly on the ground. The characteristic blossom shape of Ground Bloom Flowers is caused by the tube rapidly bumping up and down as it spins.

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MINES

Mines are basically a ground-level aerial shell burst that is directed upwards. The bottom of the tube contains a black powder lift charge, similar to that found in a shell. When ignited, the lift charge engulfs the stars in flame, igniting them as it propels them out of the tube in a V-shaped pattern. The "spread" of the stars in the sky depends on both the length and the width of the mortar. Consumer mines are typically one-shot-per-tube devices that are bunched together, resembling repeaters. Professional mines, however, are reloadable - the lift powder and stars are put in bags, which are lowered into the mortars and ignited.

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NOVELTIES

There are hundreds of different novelties, and they all work more or less the same way. The example I've chosen to illustrate here is the ever-popular tank. Tanks contain several tiny fountains that shoot multi-colored stars and often produce just enough thrust to move the device along if it's placed on a hard, level face. A small length of gray tissue firecracker-type fuse transfers the fire from the rear fountain to the front "guns" of the tank. These small fountains are only filled half way with composition, so the fuse can therefore enter from the side in order to ignite it.

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PARACHUTES

Aerial parachutes have a complex internal construction very similar to that of an aerial shell. Parachutes can come in the form of single tubes with a base, or clusters of tubes that look like a tall repeater. The launch tube is usually quite thick to withstand the forces of the powerful, noisy lift charge. When the lift charge ignites, it blasts a "parachute tube" high into the air. Meanwhile, a time fuse is burning inside of the parachute tube, which in turn ignites a tiny burst charge when the tube reaches the highest point in its flight.

Much like a model rocket, this burst (or "ejection") charge blasts the parachutes from the parachute tube. There is often a small piece of paper "wadding" between the burst charge and the parachutes to prevent the chutes from burning up. The tissue parachutes are attached to small chunks of tube filled with clay to serve as weights. They can be packed together tightly, which enables several parachutes to be put inside of one parachute tube. Sometimes the weight tube is filled with a smoke composition. A short piece of fuse transfers fire from the parachute tube's burst charge to the composition in the weight, which smokes as it drifts down from the sky. Nighttime parachutes use a steady-burning star or strobe composition in place of smoke composition.

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REPEATING FOUNTAINS

Repeating fountains are large tubes that contain many single fountains that are fused to ignite sequentially. Because of this, repeating fountains last much longer and usually have a wider variety of effects than single-tube fountains. Each of the individual fountain tubes has a hole near the bottom with a fuse coming out of it, which leads up to the top of the next tube. This fuse ignites when the tube has almost finished burning, and by the time it does, the next tube has already ignited. This sequence continues for the remainder of the tubes. Sometimes a fuse will lead to several tubes, igniting them all at once to produce an intense spray of noise and color as a sort of 'finale'. Click here to see an actual picture of the fusing of a repeating fountain.

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ROCKETS & MISSILES

Rockets are the second oldest type of firework that were originally discovered by mistake - the Chinese discovered that an open-ended firecracker propelled itself along the ground, rather than exploding. Since then, their construction has become much more complex. Rockets and missiles operate the same way; the only difference being in the method of stabilization (either fins or a stick). When the burning fuse enters the end, the cone-shaped chamber ignites within a fraction of a second. The shape of this chamber provides a very large surface area for burning to take place, creating a large volume of gas which is forced out of the back to create thrust. As a result, the rocket/missile travels in the opposite direction. Because of the rapid burning, the fuel is exhausted in a matter of seconds. The casing of the rocket is usually fairly thick so it can withstand the high pressures of the burning fuel. The internal time fuse then transmits fire to the burst charge, which explodes to break open the rocket casing and ignite the stars or reports inside.

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ROMAN CANDLES
Though roman candles seem like a simple firework, the construction process is quite complex and difficult. After a clay plug at the bottom, the roman candle tube consists of alternating layers of lift charge, stars, and delay compositions. When the fuse enters the tube, it activates a slow-burning delay composition that makes its way down. Within seconds, the delay charge reaches the first star, simultaneously igniting both it and the lift charge below it, which blows the star out of the tube. This ignites another layer of delay composition, which will light a star and the lift charge to blow it out a few seconds later. This continues until every star has been blown out of the tube.

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SMOKE DEVICES

The most famous consumer smoke device is probably the "smoke ball" or "smoke bomb", a large ball of clay with a hollow center. Inside the center is a composition that usually consists of potassium chlorate, lactose, and a powdered dye. When ignited, this composition burns at a relatively low temperature, which evaporates the dye into fine particles and disperses them into the air (so the colored "smoke" isn't actually smoke at all). The smoke composition must be "cooled off" fairly quickly after ignition, or else the dye particles will react with oxygen to burn up. This is why smoke is always observed rapidly exiting the burning chamber. If you hold a smoke device too close to a solid object, the burning particles can't get away fast enough to cool down. At this point, the device will begin emitting a flame rather than smoke.

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SNAKES & STROBES

Consumer strobes are usually small paper cups filled with a liquid composition that is allowed to dry. Strobe composition is a mixture that consists of two main parts: a composition that reacts easily, and one that doesn't. When the fuse ignites the composition, the more reactive compound burns to create a large amount of heat. This heats up the the more difficult to ignite portion of the mixture, which goes off with a sudden flash once it reaches ignition temperature. This process repeats itself over and over, gradually increasing in frequency and producing hundreds of flashes. In display fireworks, strobe composition is made into stars and put into either aerial shells or mines. Snakes are made from a slow, cool-burning composition that leaves behind a solid, porous ash that "grows" out of the pellet as it burns.

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SNAPS & PARTY POPPERS

These "trick noisemakers" have many different names, but they're all the same thing. Each of these pea-sized devices contains a few grains of sand that have been coated with a tiny amount of impact-sensitive silver fulminate (AgONC), all twisted together in a piece of tissue paper. When thrown on a hard surface (or squished between the fingers), the friction of the sand against the silver fulminate causes the latter to ignite with a quick, loud "pop".

Party poppers are another well-known and popular noisemaker, especially for children. Inside of the plastic bottle, just above the neck, there's a small explosive charge connected to a string. In the "bottle" portion of the popper are about a dozen tiny rolls of confetti paper. The string is built into the explosive charge in such a way that when pulled tight, the charge explodes, which blasts off the paper end cap and sends out streams of confetti. Neither pop-its nor party poppers are actually considered to be consumer fireworks. Rather, they are considered "trick noisemakers" which, along with toy caps and cigarette loads, fit into the 1.4S category. Therefore, they can be sold year-round in most toy shops and shopping centers.

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SPARKLERS

Old-fashioned sparklers (left) consist simply of a thin metal wire that has been coated in a metallic pyrotechnic composition. This slow-burning mixture is extremely bright and gives of thousands of tiny sparks as it burns down the length of the wire. Newer, "Morning Glory" type sparklers (right) consist of a composition-filled tube attached to a wooden stick.

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WHEELS AND SAXONS

Wheels consist of a cardboard frame to which are attached several small rockets, or "drivers". The device is usually attached by a nail to a wooden post. When the burning fuse enters each driver, the propellant burns rapidly to give off gas, which is forced out of the small nozzle to create thrust. This thrust spins the device around its axis. Unlike most rocket propellants (which are designed to lift the rocket up into the air and not give color), the propellant used in wheel drivers burns to produce rich colors, sparks, crackle, etc. Because the wheel spins so fast, it appears that there are "rings" of fire. When each driver is exhausted, the fire is transferred by another fuse to the next driver, which starts up again and continues the process (usually with a different effect). This usually happens so fast that the wheel doesn't have time to stop spinning.