Ferret Posted May 31, 2012 Posted May 31, 2012 So i'm going on my fourth year of being a pyro, and I really want to make my shell breaks look bigger this year. My pasting method is admittedly poor and I could probably get around using a booster if i used the three-strip method, but I already spend long enough pasting shells and the three-strip method would take too much time to be worth it to me. I'm mainly interested in using whistle mix as a booster because it is supposedly safer than flash. I have read that a lot of people don't use a phlegmatizer when making whistle for boosting, and simply dry screen the whistle mix. Isn't a phlegmatizer supposed to decrease the sensitivity of the whistle mix? so why leave this out when making whistle for shell boosting? The main safety concern with shell boosting is probably the closing of the shell. If you make spherical shells, you have to bang the shell closed with a dowel or rubber mallet before you can tape it shut. What does one do when that shell contains a booster? I don't know how safe it is to bang a shell closed when it contains an impact sensitive compound. Also, is their any rule of thumb for how much booster to use for each shell size? For 3" shells, I have heard of anywhere between 1g to 5g of whistle. What about for flash? Also, are their any other safety methods I should know about when boosting a shell? Does a boosted shell become impact sensitive? what if I dropped a boosted shell? So my main questions are:-Should I use a phlegmatizer when making whistle for shell boosting?-How should I close a spherical booster-laden shell?-How much booster does one use in a shell? General safety tips on boosting shells would also be appreciated.
Potassiumchlorate Posted May 31, 2012 Posted May 31, 2012 Flash isn't very impact sensitive. The greatest risk with flash is static electricity. For my own part I use H3 as a burst. That way I don't need a booster.
Ferret Posted June 12, 2012 Author Posted June 12, 2012 (edited) Has anyone here closed a boosted spherical shell by hitting/tapping it closed? because if it's safe enough for other pyros, it' safe enough for me. Maybe i'll just make up a tiny amount of flash and hit it with a hammer to see how sensitive it is to impact. edit: all right, so i just went and made 1g of standard 70/30 flash, and took a tiny pinhead size pile of it on a piece of paper, and beat the crap out of it with a hammer. nothing happened. I then lit a similar sized pile, and it burned my retinas with the intensity of light that flash is known for. so the batch was indeed flammable. so then i took a .1 or .2 gram pile of the stuff, enough to make a decent firecracker if enclosed, and hit it with a hammer (at full arms length, with ear protection) until i started getting compressed miniature pucks of flash all over my concrete sidewalk. nothing happened. so i wasted the rest of the gram of flash by taking slightly bigger piles with every test and pounding the powder into the concrete until there as nothing left to pound. The same stuff i used in those tests I use .5g of to break my 1" bombettes, and they break as hard as festival balls. so its not weak stuff. Conclusion: maybe standard sulfurless flash isn't as impact sensitive as I took it to be? I still wouldn't reccomend ramming the stuff into a rocket, but maybe it's not so dangerous to tap closed a flash boosted shell. Edited June 12, 2012 by Ferret
dagabu Posted June 12, 2012 Posted June 12, 2012 Has anyone here closed a boosted spherical shell by hitting/tapping it closed? because if it's safe enough for other pyros, it' safe enough for me. Maybe i'll just make up a tiny amount of flash and hit it with a hammer to see how sensitive it is to impact. edit: all right, so i just went and made 1g of standard 70/30 flash, and took a tiny pinhead size pile of it on a piece of paper, and beat the crap out of it with a hammer. nothing happened. I then lit a similar sized pile, and it burned my retinas with the intensity of light that flash is known for. so the batch was indeed flammable. so then i took a .1 or .2 gram pile of the stuff, enough to make a decent firecracker if enclosed, and hit it with a hammer (at full arms length, with ear protection) until i started getting compressed miniature pucks of flash all over my concrete sidewalk. nothing happened. so i wasted the rest of the gram of flash by taking slightly bigger piles with every test and pounding the powder into the concrete until there as nothing left to pound. The same stuff i used in those tests I use .5g of to break my 1" bombettes, and they break as hard as festival balls. so its not weak stuff. Conclusion: maybe standard sulfurless flash isn't as impact sensitive as I took it to be? I still wouldn't reccomend ramming the stuff into a rocket, but maybe it's not so dangerous to tap closed a flash boosted shell. I tap ALL my shell closed with an oak rod, I can't even guess how many I have made and I never feel that I am in great danger. I feel much more paranoid when pressing rockets... -dag
Ferret Posted June 13, 2012 Author Posted June 13, 2012 Just made a 3" shell with 1.5g 70/30 flash, and i'm still alive. I have good hopes for it and i think i will be boosting all my shells now.
GalFisk Posted June 17, 2012 Posted June 17, 2012 For those who want to boost with whistle, and are concerned about the sensitivity, I can recommend using benzolift instead. The wet mix method adding the KClO4 last has less risks than whistle manufacture and the finished composition is less sensitive. It's also a nice powerful lift for small shells, max 3" recommended. It burns like fast BP freely, and several hundred grams won't self-enclose, its whistle nature is only really evident when it's properly enclosed.
Seymour Posted June 17, 2012 Posted June 17, 2012 I'm with Dagabu on this one. I feel more scared when I press a 25mm ID whistle than when I close 5" salutes with 900g flash, and tap them nicely with a stick to get them fully shut.
Potassiumchlorate Posted June 19, 2012 Posted June 19, 2012 If you put a small amount of KP/Al 70:30 on an anvil, hold a hammer in your hand about 20cm above and let it drop by its own, the flash will most likely not explode. Ergo: it is not very impact sensitive. Static electricity on the other hand...
nesc39 Posted June 11, 2013 Posted June 11, 2013 I am a newb and when using flash or whistle for a booster why not put it in a small bag instead of sprinkling it on? It would seem more dangerous to have floating around in the shell rather than sealed in a bag
Mumbles Posted June 11, 2013 Posted June 11, 2013 It can be somewhat more dangerous to have flash loose in the shell as opposed to being contained in a bag in the center. A center flash bag also allows you to generally use less flash. The downsides are that the flash booster often becomes much more obvious, which can be very distracting. It also is a less lenient. There is a smaller window between under and over breaking when using a confined flash bag.
Ferret Posted June 11, 2013 Author Posted June 11, 2013 I personally like to distribute the flash throughout the entire burst charge, with the thought that this would make the burst itself more even and symmetrical. It may be just as good to dump it all in the center. On a separate note, I am planning to make a salute this year with the binary method, but I am wondering about the safety of that versus diapering the flash outside the shell and then putting it in. Last year, I diapered the flash and then contained it in a bag within the shell, so the flash could not move around inside. With the binary method, you have to leave the powders loose obviously, which seems less safe to me somehow. Although logically it should be safe, I mean, paper can't generate static electricity when rubbed by a powder, could it? Does anyone know how they make salutes in the industry? I remember seeing a dirty jobs episode with little big shots, and he actually screened the flash! made me nervous watching it...
Seymour Posted June 11, 2013 Posted June 11, 2013 They/we make salutes with as many different methods in industry as we/you use in the hobby world. I've screened flash by the ten kilo batch, though there was no sulfur in what I've screened. I actually felt safer screening it than using some of the other mixing techniques I've seen commercially. Flash is definitely rather sensitive to many stimuli, and is not just on the higher end of sensitivity, but is at the highest end for destructive power in the event of an accident. However remember that salutes are loaded, bashed shut (yes, often closed by bashing them with a stick like you do with shells), dropped on the ground, transported across the world by the million, and then slammed out of a mortar by an over sized lift charge, and then possibly be slammed across the sky by an even harder burst charge, and they can cope with all that reliably. Throw in the fact that the flash in a lot of commercial fireworks is not 70/30 but has Sulfur, MgAl and other such goodies that increase sensitivity. Do respect flash, Absolutely. But remember if it was likely to go of due to things like being loose and able to tumble, we would call it a death mix and not use it. 2
nesc39 Posted June 12, 2013 Posted June 12, 2013 I always wondered how they could seal salutes with hot glue and they don't ignite. Ive taken .5g and covered it with the hottest temp gun i had and it didnt ignite but i still dont trust it. Obviously the ignition temperature is much higher, does anyone actually know the ignition temp of 70/30 flash?
Ferret Posted June 12, 2013 Author Posted June 12, 2013 Thanks Seymour, I think that's exactly the logic I needed to hear.
mike_au Posted June 13, 2013 Posted June 13, 2013 I always wondered how they could seal salutes with hot glue and they don't ignite. Ive taken .5g and covered it with the hottest temp gun i had and it didnt ignite but i still dont trust it. Obviously the ignition temperature is much higher, does anyone actually know the ignition temp of 70/30 flash? Apparently the autoignition temp of Al powder is aroung 760degC (according to http://avogadro.chem.iastate.edu/MSDS/Al_powder.htm), so I guess flash powder is somewhere below that The bigger risk with hot guns though isn't autoignition, it is sparks due to a malfunctioning glue gun. A common solution is to get a cordless gun that heats while it is on the stand and then just relies on the nozzle retaining the heat during use.
nesc39 Posted June 16, 2013 Posted June 16, 2013 Mumbles are you there? Is it possible to ignite flash from glue gun heat?
nesc39 Posted June 16, 2013 Posted June 16, 2013 What is a flash bag made of? It's purpose is to help break the shell. With different star chemicals posing a danger and to keep friction to a minimum is its purpose? Is it fused, how is it ignited? When I go to professional displays I love the deep thunderous boom, I always wondered if this was from a salute or just the reg burst powder. Do they even put salutes in large shells? Are salutes used In shells with stars?
Seymour Posted June 17, 2013 Posted June 17, 2013 (edited) What is a flash bag made of? Paper or plastic. Usually thin... think tissue or lunch wrap (though as thick as normal A4 is fine) With different star chemicals posing a danger and to keep friction to a minimum is its purpose? Some people do it for this, but by and large the main reason is to keep the flash in the centre of the shell for symmetry and to get the most from the flash. I don't bother usually and I dump the flash in with the other burst. Is it fused, how is it ignited? The flash bag is usually attached o the end of the timefuse, or the passfire that leads from the timefuse to the centre of the shell. When I go to professional displays I love the deep thunderous boom, I always wondered if this was from a salute or just the reg burst powder. Both. Salutes do this, and medium and large shells with moderate to hard burst make a very good boom too. Do they even put salutes in large shells? Yes, you can put whatever you want in a shell and I can assure you shell makers know this. Are salutes used In shells with stars? Of course Edited June 17, 2013 by Seymour
nesc39 Posted June 17, 2013 Posted June 17, 2013 "The flash bag is usually attached o the end of the timefuse, or the passfire that leads from the timefuse to the centre of the shell." ----- what is a passfire and what is the point of it. Why not just end the timefuse in the middle of the shell and duhhhh I just answered my own question. I only have seen 4" shells and under and the time fuse makes it to the center of the shell but I'm guessing in a larger shell the delay isn't proportionate to shell size and the timefuse probably doesn't reach the center and that's what a passfire is for???
Seymour Posted June 17, 2013 Posted June 17, 2013 Correct answer Sometimes in smaller shells too when you have shorter delays. Several methods for the passfire are used, and all revolve around extending the fuse with a paper tube and filling it with a material to pass the fire instantly. This is usually Black powder gain or Black match. Realizing that quick match is a pre made passfire with a paper sleeve often just the right size to fit over timefuse, I just cut the appropriate length of it to graft to the timefuse. I think Mumbles is on to this short cut too.
Mumbles Posted June 18, 2013 Posted June 18, 2013 It will depend on what I'm doing, but yeah, quickmatching from the time fuse to the center of the shell is what I do with typical shells. Seymour pretty well covered everything else. Flash bags are not very common in amateur manufacture. They're used for a few specialized effects, like spider shells. Other than that, they're typically reserved as a cost cutting measure used previously in domestic US manufacture. They were used readily in finale chains where the pattern or performance wasn't very critical. Over time the processes were refined and used in fairly nice shells, but from what I've been told, it's more of a hybrid between traditional and the "new" flash bag construction. Some of the italian and spanish shells are reported to use larger flash bags of slower flash powder. A lot of the information on this, as well as the hybrid techniques still is fairly secretive though.
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