Click Fireworks to Enlarge

Skylighter Fireworks Tips September 10, 2008 -- Issue #112 IN THIS ISSUE: Easy-to-Make 2-Inch Plastic Cylinder Shells How to Grind Potassium Nitrate Save Big with Skylighter's 2-Inch Shell Kit Visit Skylighter's Project Plans

This week's Fireworks Tips is directed at all of you aspiring fireworks makers who have been waiting for a nice easy project. Ned's worked out a very simple 2-inch canister shell, using flying fish fuse or homemade stars.

What makes this a no-brainer first project is you can get a kit containing just about everything you'll need to build your first shells. Just add some black powder, glue and some mortar tubes. Better yet, order before midnight, September 12th, 2008, and you can get 3 free mortar tubes to launch your shells.

Come on, how many times have you said to yourself "next year I'm going to make my own fireworks for New Years or the 4th of July?" With Ned's instructions and Skylighter's 2-inch shell kit, now is the time. Well, what are you waiting for? Get your own 2-inch flying fish, canister shell kit today.

2-inch Plastic Cylinder Shell Kit, #KT0040

$45.73

EASY-TO-MAKE 2-INCH PLASTIC CYLINDER SHELLS

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



After using flying fish fuse to make a reloadable star-gun cake, I thought it might be nice to go a little further and make some simple, small shells using that same fuse. I'll also make some star shells using the same methods.

These little, quick-and-easy shells are perfect for testing stars in a star shell, and also for simple shells for a backyard display. You can even attach gold glitter rising tails to the top of them.

With a little assembly line, a bunch of these small shells can be quickly made for launch the same day.

I'll be starting with Skylighter #PL1020 plastic aerial fireworks shell casings. These casings come with a 3/32-inch hole in the cap to accommodate visco time fuse. One could also use PL1022 casings, which come with a 7/32-inch hole in the cap. (I won't be using the fuse hole in the cap, so the size of the hole makes no difference.)


I'll also be using 1/4-inch Chinese time fuse, GN2010, and super-fast paper firecracker fuse, GN1205. This same paper fuse can be used as a quickmatch leader by wrapping it with peel-and-stick aluminum foil duct-tape, or standard GN3001 quickmatch may be used.

Shell Construction

I will not be inserting time fuse in the caps of these shells, but through 1/4-inch holes drilled in the bottom of the plastic cans. This makes the assembly that I'm about to describe really easy.


In Fireworks Tips #99, One Way to Make a Really Nice 4-Inch Plastic Ball Shell, I describe 1/4-inch time fuse, how to determine its burn rate, and how to split and cross-match it.

The roll of time fuse that I'm currently using burns at a rate of 2.2 seconds per inch. For these little shells I want a 1.5-second time delay, which is about 5/8-inch of time fuse. I also add one inch to that length because I'll be splitting each end 1/2-inch for the cross-matching, so I cut 1-5/8-inch lengths of the time fuses for these six shells.

I split and cross-match one end of each fuse with short pieces of black-match out of the fast paper firecracker fuse or out of quickmatch.


After making sure the time fuses fit through the holes in the plastic cans, I put a ring of hot-glue around the mid-point of one fuse at a time, and insert the fuses into the plastic casings. I pull each fuse through until the cross-matching on the fuse is almost against the bottom of the can, keeping the cross-matching just out of the inside hot-glue.


Then I add another bead of hot-glue around the outside of the time fuse to really seal the lift gasses out of the shell when it is launched.


I fill the holes and recesses in the casing caps with hot-glue now.


In Fireworks Tips #96, I demonstrated Making and Testing High-Powered Black Powder. This article included several different ways of making and granulating black powder. In the following step, either granulated BP or BP coated on rice hulls may be used. Either commercial or homemade black powder would be suitable.

I fill the bottom of the shell can with BP coated rice hulls up to the level of the tip of the time fuse.


Then I cut a circle out of cheap tissue paper and press it down on top of the black powder charge. A small paper cup, with the sides slit with scissors, is the perfect size for pushing the tissue paper down into the plastic can.


Then it is a simple matter of filling the shell casings with stars or flying fish fuse, up to a level which will allow the caps to be glued on.


Note: In some of these photos, I've temporarily taped the fused end of the shells that I'm working on onto the open end of empty casings so that the shell will stand upright during construction.

Next simply glue on the shell caps with PVC plumbing cement or thickened methylene chloride. I also further secure the cap on with a layer of masking tape.


The outside end of the time fuse is now split with a razor blade, and cross-matching is inserted and tied in place.

Lifting and Leadering the Shells

I'll be shooting these babies out of a 2-1/2-inch HDPE mortar that I own. It's the smallest one that I have that these shells will fit into, and they will be a slightly loose fit.

I weigh out 1/2-ounce of 2FA lift powder for each shell. Fg or FFg commercial sporting black powder could also be used.

I place the lift powder in a plastic baggie, insert a piece of quickmatch leader with some of the black match bared, and tape the baggie closed around the quickmatch leader. The excess baggie plastic is trimmed off with scissors.


I hot-glue the leader to the side of the shell, and cover the lift powder and time-fuse with aluminum-foil duct tape.


Then I tape some lengths of visco safety fuse into the leaders, and the shells are ready to be loaded into mortars and fired.

The Aftermath

My goal with this type of shell construction was the creation of a sort of "sky-mine" effect, where the shell contents are propelled out of the open end of the shell casing. I did not want the whole shell casing splitting open and bursting like a typical aerial shell. I thought the sky-mine effect would look better, especially with the flying fish fuse.

If I had wanted a more traditional shell starburst, I would have mixed the black-powder-rice-hull burst with the stars throughout the shell, and perhaps would have used some of the slow-flash booster.

The sky-mine type of burst was achieved with the shells made in this project, as evidenced by the plastic parts when they were retrieved from the field after firing.


Here's a link to a video of three of these little shells: one made with lemon crackling flying fish, one with red crackling flying fish, and one made with variegated (multi-colored) stars.

Note: I tried a shell with falling leaves fuse, and while some of the fuse pieces lit, many did not. I've heard that some of these "special effects" fuses, in order to ensure good ignition, need to be primed by dipping their ends in nitrocellulose lacquer and then in fine black powder. I did not try that, though, and will leave it up to the reader's experimentation.

A "Peanut" Shell Using Plastic Shell Casings

It is easy to construct a peanut shell with these small plastic shell casings. (A peanut shell is actually a shell that breaks twice, with a delay between breaks. It is called a peanut, because some shells made this way are constructed of two small, spherical shells. When taped together they resemble a peanut.)

First I construct two of the shells, in this case using multi-colored stars, using the same construction as outlined above, except that I want a one-second delay on the first shell, and a two-second delay on the second shell.

To accomplish this, I cut one piece of fuse 1-7/16-inches long, and the other piece 1-7/8-inches long. After splitting and cross-matching, this will produce the two delays I am looking for.

After I construct the two shells, I hot-glue 1-1/2-inch chipboard discs into the recesses in the ends of the shells to make those ends flat and flush.


Then, I hot-glue the two shells end-to-end, and cross-match the two time fuses. I also reinforce the joint between the shells with two turns of masking tape.


The shell is lifted and leadered as the shells above were, except I increased the amount of lift powder to 0.65 ounce.


The quickmatch is hot glued to the side of the shell, and next to the top time fuse. I open up a small "window" in the side of the quickmatch so that fire transfers to the top time fuse when the leader lights.


Then it's simply a matter of using aluminum foil tape to cover the bottom of the shell and the passfire "window" at the top.


Inserting some visco safety fuse finishes off the shell, and she's ready for the firing line.

Here's a link to a video of this peanut shell.

Note: This type of shell, where the time fuses of both shells are ignited at the same time during the shell's lift out of the mortar, is called a peanut shell, or a "piled shell." A "multiple-break" shell is one in which each successive shell takes fire from the burst of the preceding one.

Have fun with these simple shells,

Ned
ngorski@skylighter.com

USING A COFFEE/SPICE GRINDER TO PULVERIZE POTASSIUM NITRATE

If one does not have a ball mill there is another option for grinding coarse potassium nitrate into a free flowing, fine powder. Coffee and spice grinders work well for grinding small batches of individual chemicals.

Even though I have a ball mill, there are times when the coffee grinders come in handy for pulverizing smaller batches of chemicals. I have some Parlon, most of which will pass through a 40-mesh screen, but which has some larger particles as well. I'll take those larger bits and run them through the coffee grinder in order to reduce them to smaller particles.

Warning: Dedicate one grinder for use on oxidizers, and another one for use on fuels such as charcoal. We don't want fires or explosions when we're grinding chemicals. Never grind complete or mixed compositions such as black powder in a coffee grinder.

I have found two kinds of coffee grinders: blade-grinders and burr-mills. Don't get a burr-mill; they don't work as well as blade-grinders. The blade-grinders have a stainless steel blender type blade that spins at high speeds in the bottom of the material cup, chopping the material into small bits in the process.


I have purchased many of the smaller, less expensive, blade-type coffee grinders. But here's the warning: they really don't last too long if you mill chemicals for a minute or two at a time. To use them, mill your chemicals in pulses of a few seconds at a time. I've found that shaking them while pulse-grinding gives me the fastest results.

Grinding Potassium Nitrate with a Blade Mill

The Kitchenaid blade mill has a larger hopper, and a larger, more powerful motor, and is rated to be used often. I'm hoping that it will last longer than the $13 WalMart models I've been using.

I put a half-cup, 4.6 ounces, of 12-mesh potassium nitrate into its hopper, pressed down on its lid to start it, and pulse-milled the powder for just under a minute, shaking the grinder now and then in the process.

Quite a bit of fine powder started to accumulate on the inside top of the clear lid as it milled. I dumped the ground chemical onto my 100-mesh screen, and used a fine paint brush to clean off any that was clinging to the inside of the hopper or the lid.

About three-fourths of this milled powder would pass through the 100 mesh screen, and I set aside that which wouldn't to be ground again with the next batch.

Conclusion

Granular potassium nitrate can be dried if necessary, and ground easily with a ball mill or with a coffee blade mill, so that it passes through a 100-mesh screen and is ready to be used in pyrotechnic compositions.


There's no reason to put off building aerial shells any longer. It doesn't get any easier than this. There're no chemicals to mix, no stars to dry and no pasting. This is the perfect kit for a first-time shell builder. Just follow Ned's instructions and you can have your first shell built in 10 minutes. You can even fire your shells the same day you build them.

Even experienced shell builders can enjoy these quick, easy-to-make shells. When you're in need of a pyro fix, these are the fastest way to get homemade shells into the air, and they are quiet to boot.

The kit contains enough plastic shells, time fuse, visco, and crackling Flying Fish fuse to make 12, two-inch crackling flying fish canister shells. You just supply the black powder, and some glue. Here's what you get in the 2-inch Plastic Cylinder Shell Kit:

	Retail Value
Green Crackling Flying Fish Fuse, 100 ft.	$29.95
Red Crackling Flying Fish Fuse, 100 ft.	$29.95
1/4 inch, Chinese Time fuse, 1 ft.	$1.54
Super-Fast Paper Firecracker Fuse, 100 ft.	$15.61
#5 shell w\Time fuse hole, 12 shells	$10.92
Chinese Green Visco, 10 ft.	$2.10
Total Retail Value	$90.07
Order now for just	$45.73

And if you order before midnight Friday, September 12th, 2008, we'll give you an early-bird bonus of 3 #100 Mortars, a $10.60 value. That's right: you get the kit to make the shells and free mortar tubes to launch them! That makes a total retail value of $100.67 that you get for $45.73, if you order by midnight Friday, September 12th, 2008.

Note: This Special ends midnight Tuesday, September 16th, 2008. If you take advantage of the early bird special, you will not see the free mortar tubes in your shopping cart. We will add your free tubes here at the warehouse. Also, shipping costs may be higher than what you see in your shopping cart, because the weight of the free mortar tubes will not have been calculated there.

2-inch Plastic Cylinder Shell Kit, #KT0040

$45.73