dave321 Posted April 15, 2015 Posted April 15, 2015 I was thinking how useful a modified dragons egg composition would be to simulate a theatrical spark hit ?a small amount on a blank fusehead perhaps ? think titanium or magnalium for sparks.It would be essential to obtain a good bright throw of sparks, loud bang not essential. before I try a few things out I thought I would throw this out there for a "best" starting composition as it were ...ideas?
FlaMtnBkr Posted April 16, 2015 Posted April 16, 2015 DE comp with added titanium will throw a nice spray of sparks. The problem I see with DE is the delay during the smolder phase. I dont think you would be able to accurately time the effect but maybe precise timing isn't needed. They also need a way to get the entire surface going which is usually a layer of prime. This might also be problematic?
dave321 Posted April 16, 2015 Author Posted April 16, 2015 hi flamtnbkr, yes I think you are absolutely correct re the smoulder phase and the surface covering effect. I cannot think of a way around this at the moment...maybe try to get a very quick smoulder phase using fine magnalium ? I was trying to think outside the box.I do think the thermitic compositions might be the way to go, when dragons eggs go they have a nice crack and very desirable excellent spread, ideall fora bullet richochet effect ignition of a thermite from a bridgewire is not going to happen so a suitable ignite composition will have to be used. any further comments welcome
FlaMtnBkr Posted April 16, 2015 Posted April 16, 2015 If you don't think the delay will be a huge issue, this is what I would try. I would prime a good single pop DE that contains a little ti with something like a dark relay prime. I was thinking glusatz because it produces little light and makes a fairly hard 'clinker' ash. The problem with that is it burns really slow unmilled and might not cover the entire DE quickly enough with heat. Then glue the DE directly to an e-match with an NC slurry so the match gets the prime going. I was thinking the glusatz might be good since it makes a hard ash and isn't an aggresive burn so might stay in place. Probably would need to make your own match that doesnt have an aggressive pyrogen. Or make the leads with a bridge wire or a conductive pyrogen and then use the slurry to glue the DE on be the pyrogen that takes fire. If the match pops the egg off or drops it you might be able to add something that holds it in place. Something like a square plastic tube that I'm sure could be bought from a plastics store. Or even brass to test from the hardware store. Ace hardware has what I'm thinking of if you have those. Then cut a slice off the tube and put the egg in the center and the match in a corner that is empty if the egg is round. Then glue in place with maybe straight NCL. You could take a piece of stainless safety wire and wrap around the center to lock the egg in place and then twist the wires with pliers to tighten it up. Then leave the tails hanging off and you could use them to wrap around something to mount it where you want and hold the match leads out of the way. If you can't follow that I can try to draw a picture. Not saying it will work but it's what popped in my head to try. Maybe it can give you an idea. They might not pop right when you fire them but if you fire a few in series the time between pops will probably be pretty close to the timing you set between pops since they should all have a similar delay. Good luck.
rogeryermaw Posted April 18, 2015 Posted April 18, 2015 exploding bridgewire dipped in n.c. and sprinkled with fine mgal or ti? you'd get a nice snap and spray plus ebw have no smoulder delay. maybe set off with a capacitive discharge initiator. electronics guys?
dave321 Posted April 18, 2015 Author Posted April 18, 2015 exploding bridgewire dipped in n.c. and sprinkled with fine mgal or ti? you'd get a nice snap and spray plus ebw have no smoulder delay. maybe set off with a capacitive discharge initiator. electronics guys? interesting idea that.unfortunately it requires high voltages which I want to avoid
dave321 Posted April 18, 2015 Author Posted April 18, 2015 interesting observation......... dragons egg compositionbismuth trioxide 37.5copper oxide 37.5magnalium 250# 25.0nitrocellulose +10 above is very loud with several cracks...........add +10%Ti(100um) and the effect is completely destroyed giving a fast burning comp with plenty of sparks but no loud pops etc
dave321 Posted April 19, 2015 Author Posted April 19, 2015 ok using +10% titanium 300um works a treat for the pops and sparks just need to make it work on an ematch..............maybe a bit of boron will help ignition.......
FlaMtnBkr Posted April 19, 2015 Posted April 19, 2015 Be careful with bismuth trioxide and boron. I know there have been a few accidents with those 2 chemicals involved.
dave321 Posted April 19, 2015 Author Posted April 19, 2015 Be careful with bismuth trioxide and boron. I know there have been a few accidents with those 2 chemicals involved. +10% boron completely killed the pops, maybe less might help yes, bismuth trioxide and boron is very fast and very hot
FlaMtnBkr Posted April 19, 2015 Posted April 19, 2015 A bit of magnesium will speed up the smolder but might take it from a single pop egg to multiple pops. I would start with only 2 or 3% to see what happens. A small amount of oxidizer like perc will also help speed up the smolder and acts like additional NC I believe. I would start about like the magnesium above. Maybe some things to try.
dave321 Posted April 19, 2015 Author Posted April 19, 2015 A bit of magnesium will speed up the smolder but might take it from a single pop egg to multiple pops. I would start with only 2 or 3% to see what happens. A small amount of oxidizer like perc will also help speed up the smolder and acts like additional NC I believe. I would start about like the magnesium above. Maybe some things to try. I will try that out
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