JohnWI Posted June 30 Posted June 30 I've been reading whatever I can find about amateur pyrotechnics. It's unfortunate, but a lot of the available information is of questionable quality/safety. I did read some interesting things about how traditional "globe salutes" (aka cherry bombs) were made of paper cups nested together, then tumbled with layers of silicate and saw dust. What I found a little concerning was that after they were formed and dried, a hole was drilled into it for a fuse. I'm just curious if that is a safe practice or not. I'm planning to make things significantly smaller--but even half that power, going off in your hands, would be a really ugly situation.
All10Fingers Posted July 1 Posted July 1 Probably depends on the method used to make the hole. Again I can only share from my own limited experience. I always make the hole first,add the fuse, then add the mix to the other cup before glueing the other on top. I use confetti and/or candy wrappers instead of sawdust. I've read probably everything you have online and am familiar with all the conflicting information. I believe traditional cherrys were tumble mixed after they've been sealed. Which is why the fuse is added last. If your powder is properly and thoroughly mixed, it's not necessary to tumble them, therefore no reason you couldn't add the fuse first. I guess I am still fairly new to this stuff. But when I was really new, I'd get hung up on trying to exactly replicate the process if others online. And was really giving myself headaches over it. Now I dumpster dive for my shell building material and make stars with tree sap. So take a shot and see what happens. Your second will probably be better than your first. And the third better than the second, and so on untill you develop a method that works for you.
pyrokid Posted July 2 Posted July 2 No one said you need to hold the salute while the fuse hole is drilled. The first design consideration would be to separate the human from the hazardous process, in this context the would entail building a drilling jig along with a semi automated drilling apparatus. Practically I would not want my contraption blown up so one idea is to carefully control the drill depth so as to minimize the chance of accidental ignition. I know of one formerly prominent domestic manufacturer that used high rpm air powered drills to set fuse holes into pressed tube effects.
Kalifireworks Posted July 2 Posted July 2 Why would you drill it instead of punching with a brass needle? Thats much more common.
Arthur Posted July 2 Posted July 2 Many hazardous operations are outsourced to less regulated parts of the world. It's your responsibility to make your hobby as safe as possible. it's usually possible to make the fuse hole then fill the hemis, then put everything together, perhaps you can fill the hemis through the hole. gluing the fuse in place is a vastly lesser ignition risk than using a power drill near flash powder.
JohnWI Posted July 4 Author Posted July 4 Thank you for the responses folks. My gut feeling is that it would be safe. But with a great deal at stake (ie, my fingers, vision...) I will definitely stay away from doing it. I just brought it up, because one of the old 90's Delta Publications books on the subject literally had photos of drilling holes in pyro casings after they were full. I have no idea what could happen from steel/paper friction, or what the odds are that motor sparking would do something. But again, with fingers and vision at stake, it's not a gamble I'm going to take.
Richtee Posted July 4 Posted July 4 Twist a bit with your hand. Or not. I have many times. A punch needle is similar. YMMV.
Arthur Posted July 4 Posted July 4 Drill the tube before filling, then cover the hole with a temporary paper tape and fill. Remove paper tape and insert fuse, glue fuse in place. AS you say the potential loss is great and valuable.
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