Chaining Fuse: The Long And The Short Of It
Chaining Fuse: The Long And Short Of It
By: Matthew Kleinmann
Either in conjunction with an electronic firing system, or on its own, most pyros, at some point in their careers, wind up wanting to chain multiple fireworks together. This can let you be in two places at once, in that once you have lit a chain, as long as the integrity of the chain remains intact, once it is lit, it will keep going. This will allow you to go and shoot other things while the chain does its thing. Or, it will give you a few minutes to sit back and watch! It is surprising how many pyros out there never get to see fireworks! You can also have multiple chains. Generally, things that are chained are in reasonable physical proximity to each other, as you need to run some type of pyrotechnic fuse between them.
There are two basic types of pyrotechnic fuse, fast burning and slow burning. Fast burning fuse, sometimes called quick match, burns very fast, on the order of many feet per second. Fast enough that if you have a few things chained with it that are just a few feet apart, to the casual observer; they will all go at the same time.
The other type of pyrotechnic fuse is visco. This is a much slower burning fuse that also comes in different burn rates. A typical burn rate for common green visco is 3 seconds per inch or 36 seconds per foot. If you want to get down to tight timing you should measure off a few pieces and work out a calibration factor for the exact material that you have.
If you need to get down to split second timing, there is no getting away from electronic firing, with a system that can accommodate many shots, and use a separate electronic match on each effect. However you have the cost of the product you are going to shoot, the cost of a large firing system, and the cost of all the the electronic matches. You can buy many years worth of quick match and visco with that same money.
With clever use of quick match and visco you can create time delays. If you are also chaining a lot of effects together, you can also create delays by trimming off more and more of the visco that goes into the effects.
For example if you have a rack that holds 20 aerial shells, and each shell has 2 feet of visco sticking out of it, you can trim the visco on each shell back one inch more than the one before it, and make up the size difference with quick match so the fuses to the shells are all the same length again, but the first one now has 24 inches of visco and no quick match and the last one has been trimmed down to 4 inches of visco and has 20 inches of quick match added. Save the visco you trim. Now take one last piece of quick match and tie each of those fuses into that one piece. Even if you use a couple feet of quick match it will make almost no difference in the timing. Tie one end of the quick match to an electronic match or a piece of visco and you are good to go.
Some safety notes are in order here. First, if you are going to tie things together, make sure everything is securely fixed in place. If you are using racks make sure that they are on a stable stand, and you always want to fire shells perpendicular to your audience so if one of the racks falls over, the shells will not be fired into where your audience is, but to one side or the other of them. If you are using single mortar tubes you can hammer pieces of rebar or landscaping nails into the ground and securely tape the mortar tubes to them. You can also use a wooden box and fill it up with play sand and use that to secure the mortar tubes in place. Use only a fine play sand. You don’t want anything with rocks in it that could fly if a shell blows up in the tube! Also only use approved racks or mortar tubes. And make sure you follow the manufacturer's recommendation for the audience setback, or 70 feet of setback per inch of shell, whichever is greater. So a 2” shell would require a 140 foot setback.
Remember that once you start a chain it can be hard to stop, so unlike hand lighting if something goes wrong it will be considerable harder to stop it.
And last if you are going to be starting the chains by hand, make sure that you have added at least enough visco to the start of the piece of quick match that will start the chain as an unmodified effect has. So in our example, the shortest shell now has only 4” of visco left on it, and the longest, the unmodified one has 24”. We would add 20” of visco (and we just happen to have a 20” piece that we snipped off the shortest shell) to the start of the main quick match. This preserves the manufacturer's safety protocol for you having enough time to make a safe egress after starting the chain. Note that the effects after the first one will not have this delay; this is just a start delay to allow you to get back from the entire chained group of effects.
Also, don’t go thinking that you can only chain shells. You can chain anything that starts with a fuse. Cakes and spinners, fountains, novelties etc can all be fused in with everything else. The kinds of cool effects are only limited by your budget and your imagination. And this time of year Mess’s always has some great sales going on and cool new stuff coming in.
Consider things like cakes or fountains flanking spinners, and then going into a barrage of criss crossed roman candles. Or fountain cakes that overlap each other with an interesting cake or fountain in the center. The possibilities are endless, and the folks who come to see your show will appreciate your unique take on how you deployed the devices. By now people have seen pretty much all the effects so if you want to ooh and aah the audience you need to think a little bit outside of the box.
And last, for those of you who have never tried tying things together here is how I do it. Quick match is like a paper tube with some strands of black powder coated cotton in it. You need to practice slightly bending the quick match and with a pair of scissors, cut a slit in the outside paper on one half, so you can slip the visco from a device into that slit. You want the visco from the device sitting right on the black cotton strands in the quick match. I try to overlap at least an inch. Once you have the visco in place, secure the joint with some masking tape. If you are setting up a big series in advance and it will be man handled a bit, you can wrap string around the joints too, or small tie wraps. The idea is to try and strain relief the joint.
Visco to quick match at an end of the quick match is easy. Just make sure that you can see the black cotton strands in the quick match before stuffing the visco in the end. Make sure you can see them overlap and tape the joint up with masking tape.
Quick match to quick match is a bit more interesting. There are a lot of ways people do it. I have very few problems with this method. On the first of the two pieces of quick match to be joined strip the paper back about an inch, so the black cotton strands stick out. On the other end, cut a slit about an inch and a half long into the end of the paper. Now gently spread the paper open so you can see the black cotton sitting in the cup the paper is now making under the cotton. Lay the first black cotton strands on top of the existing strands. The paper from the second piece of quick match should extend beyond where the cotton sticks out of the first piece. Now fold the paper back into the position that it was originally in. It should have both sets of the black cotton touching and the paper from the first piece should extend all the way over the joint and over a bit of the other matches paper. Now, wrap the entire area with a few turns of masking tape. You may want to try this a few times until you get the hang of it, but it is not hard.
The last things you may want or need to tie are electronic matches to quick match or visco. If you are using the clothespin type electronic matches, it is ultra simple. Clip it on the visco or peel a bit of the paper back from the quick match and clip it on the black cotton strands inside. If you are using the little round rubber quick matches, for visco you can do one of two things. One is stick the visco in the hole in the rubber end, make sure it has bottomed out, and tape it in place. Or you can gently pull the rubber head off the match and tape the little piece of pyrotechnic material right to the side of the visco. For electronic matches into quick match I generally pull the rubber head off and stuff the little match head down into the center of the black match a few inches by the wires, and tape the end shut. Some pyros will slit the quick match so there is an exposed area of the black cotton showing, and bend that into a Vee with the slit at the base of the Vee, then stick the rubber match head in the crotch of the V so the hole is abutting the exposed black cotton. Then they will wrap a few turns of the wire to securely hold the V in that position, and secure the whole thing with masking tape.
None of this is hard; it is more arts and crafts. Just go slow and make sure all of your joints overlap, and seal and secure things with tape. If you get something that does not go off, dissect the joint and see why it failed, and learn from your mistakes.
One last trick from the pros: Relights. If you have many devices chained, and I have had finales with 500 shots or more, that have all been chained. You want to add some relights. These are secondary and tertiary lighting fuses. If the chain breaks or goes out, you can hit one of the relights. I generally put between 2 and 5 in depending on the size of the chain. Note that if you hit a relight, it will start firing from both ends. That is it will burn backwards from where it is back to where the break is, and at the same time will continue forward from that point. It is a good idea to keep the relights in order so if you need to use one there is a minimum amount of overlap. You could hit the one at the far end of the chain and have no overlap, but many people build chains so they build up to something and really do want to save that for last.
Hopefully you have gotten some thoughts and ideas for putting on your most awesome show to date. Stop by the store or check out the website to see what new products they have and start thinking about how to link and combine them for a brand new look. The folks there are always happy to help you pick the right products, and like most pyros, they love to talk shop!
Matthew Kleinmann Is a professional, licensed pyrotechnician and a staff writer for Mess’s Fireworks.