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theatrical concussion flash


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#1 dave321

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Posted 11 March 2013 - 01:27 PM

not sure if this belongs in the HE section, if so please move

am i right in thinking most concussion compositions for use in a concussion mortar are based on

magnesium /strontium nitrate ?

or is 70/30 also used ?............is this more "explosive / noisy" than the above magnesium comp?

any reason the following comp could not be used as it is based on a reformulated military simulator mix ?

strontium nitrate 53.5
aluminium 40
sulphur 5 reduces ignition temp.
boric acid 1 counters potential nitrate aluminium reaction
cabosil 0.5

these compositions are design for noise not light.

i am aware that each manufacturer marries their composition for use in their own mortar for safety reasons

on a seperate note maybe the forum needs another section specifically for theatrical/stage /spfx pyro ?

dave
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#2 bikemaster

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Posted 11 March 2013 - 02:30 PM

I use a lot of "Le maitre" and "NextFx" concussion type flash powder.I am pretty sure they use the 70:30 we all know, using potassium perchlorate and aluminium flake or magnalium.
The composition you just show content sulphur... this is not really good if you are doing a show in a theater and it start smeling SO2 after each concussion.

#3 Mumbles

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Posted 11 March 2013 - 04:13 PM

They generally come as 2 part mixes. I'd imagine shipping would be a pain otherwise. They're generally formulated so that they can be mixed by volume. I also believe they're a bit more tame than straight 70:30 with black Al, but that might just come from fillers/blends of materials needed to get equal volume compositions.
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#4 dave321

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Posted 12 March 2013 - 06:40 AM

using 0.5g of each :-

std 70/30 gives a small thud unconfined

whereas

strontium nitrate 53.5
aluminium 40
sulphur 5 reduces ignition temp.
boric acid 1 counters potential nitrate aluminium reaction
cabosil 0.5 flow agent

is fast but gives no "thud" when unconfined, quite a "soft" flash.
larger amounts and confined, is of course another matter, i am sure it would perform as it were.

dave
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