41 replies to this topic

[d3v]

I have read about concussion powder but it never stated it's composition. It is a sub-type of flash powder and is considered the loudest of flash. Does anyone have any information about it?

[portfire]

It is Flash Powder. It's used in theatrical indoor SFX, and comes Binary form, A+B. Once mixed It's placed in to 'Flash Pots', the effect is to replicate a sonic boom, or rather more a concussion wave. You must be a trained professional with the relevant paper work to obtain and use it.

Nice first post BTW....Asking about Flash. Tut tut

Edited by portfire, 13 August 2008 - 06:53 AM.

[d3v]

The reason I ask is because we have a yearly firework display during Summer paid for by the council and there is always a large salute barrage that sets off car alarms for a good 40ft radius I'd say. Bloody loud!

And could you please explain to me what you mean by "Binary form, A+B", or alternatively link to some sort of web page that explains it. Thanks!


p.s sorry if it goes against the grain here to ask about flash so early.

[Mortartube]

Basically you have a bottle marked A and one marked B. You mix the two on site just before you load the concussion mortar and you have flash. This makes it as safe as possible for transport and storage right up to the very last possible moment before loading.

Concussion mortars are made out of VERY thick walled steel and have a recommended number of shots before discarding.

It is possible that the display uses plastic bottle ground maroons instead of concussion mortars.

People are often suspicious of a first post that enquires about flash as it can be used for "No good" and there are far safer compositions to make before you have the experience to use flash. One mistake with very little flash can be instantly fatal.

You can see why people are so cautious about flash from this video. The first firing is one pound (454g) of flash. Not a lot weight wise really is it. Imagine you were standing using it when this happened.

Edited by Mortartube, 13 August 2008 - 10:53 AM.

[d3v]

Good god that is like C4 going off. Thanks for the video. In that weight, is the flash actually detonating like HE?

In my experience, flash made of KNIO4 + AL is perfectly stable and safe. Never have I had an accidental ignition even when mixing via gently swirling the two chemicals in a plastic jar.


I use flash as the breaking charge in cylindrical shells. I normally use about 5 grams in a 1.5inch shell and this gives a good report but I do love sound so I'm looking for the loudest flash comp I can get for use in the bursting charge.

I've looked at US army flash comps used in their artillery simulator salutes and the comp is KCLO4 64%, AL dark flake 22.5%, sulpher 10% and atimony sulphide 3.5%. I presume this comp is concussion flash becuase I would assume the artillary/grenade simulators would need to sound as loud as deep as possible like HE??

It is possible that the display uses plastic bottle ground maroons instead of concussion mortars.

Do you mean you think the concussion powder was ignited gound-level? If so, the answer is no. I saw the burst go-off then the immense report after. They are colourless, pure air salutes to finish off the display. They always do a 10 or so barrage of these babies at the end.

Edited by d3v, 13 August 2008 - 12:59 PM.

[karlfoxman]

d3v: Flash is not safe, always respect the stuff! Anyone that says its safe is yet to have an accident using it, you could go for a very long time with not having an accident. All it takes is a tiny spark or some friction to set the stuff off, when It does go of we all know what can happen. And Im keen to know how much you mix at one time? Even 5g in a bottle going fo could take your fingers off with ease, the heat would burn skin badly and debris could render you blind. Is it really worth it? The 'safest' way to mix it is the diaper method. I strongly advise you to do some research, its not all about the biggest bang, 5g is overkill for a 1.5" shell!

You seem very flash happy and we dont really like that, its a dangerous way to be.

Also KCLO4 is Potassium Perchlorate, a quick warning I am keeping a close eye on this thread.

Edited by karlfoxman, 13 August 2008 - 12:49 PM.

[d3v]

I do respect flash and my rules are to never mix more than 10g at a time and especially never to ram/compress it. If I'm not mistaken, as long as it is not compressed or hit, then flash is safe to handle.
As for 5g being overkill surely that's just personal preference. I consider loud reports to be equally important as colour.


Can we please discuss concussion powder. Why is it considered so dangerous, and what is it's composition made up of?


p.s typo fixed above, thanks.

Edited by d3v, 13 August 2008 - 12:58 PM.

[karlfoxman]

Ok, im not here to have a go at anyone just to make sure people show proper safe working practice. I would still stop using plastic bottles for mixing and stick with the daiper method. Flash and noise certainly as its place in fireworks, as I build Beraq and other colour flash units I would be wrong in saying it has no place. So long as its handled as safely as one can then your less likely to be hurt or hurt someone. Carry on with the discussion and stay away from talking about HE as it has no place being talked about on this forum, remember this is puplic forum and we know very well not only hobyists look through these pages.

Stay Green, and enjoy your stay.

[Pretty green flames]

Well, an alternative to flash is our humble Black powder, with the correct granulation and mortar you can produce one hell of a sound.

Just keep in midn the so called "thunder mug" has walls that are ATLEAST 1" thick for a 2" ID mortar, and this is for BP and nothing else, I suspect that Flash would require even heavier walls and even then, my mind tells me that putting flash in a steel/iron pot and igniting it is a bad idea, stick to black powder, relatively speaking it is safer.

[pyrotrev]

I had occasion to use some professional (LeMaitre) 20g concussion charges last year and I'm pretty sure from the smell of the smoke and the powder that leaked from a couple of them (they're of quite lightweight construction) that they were straight 70/30 flash.

Edited by pyrotrev, 14 August 2008 - 12:14 PM.

[Creepin_pyro]

I had occasion to use some professional (LeMaitre) 20g concussion charges last year and I'm pretty sure from the smell of the smoke and the powder that leaked from a couple of them (they're of quite lightweight construction) that they were straight 70/30 flash.

That would be correct. 'Concussion' powder, at least the 3 different ones I've used, are standard flash in binary form. The MSDS' back this up, only listing Perc and Al as the ingredients.

[d3v]

Really? So why is it called concussion powder? Is it to do with the construction of the casing and/or the weight of the charge?
I'd guess that the ones I hear every year would have to of been 35g or more of flash.

If it's just standard perc/al then why must they be mixed on-site?

Edited by d3v, 14 August 2008 - 02:57 PM.

[Mortartube]

It is safer to mix them on site than transport ready mixed flash. They (the component chemicals) remain as safe as possible up until use.

[d3v]

Ok but if concussion powder is simply industry standard flash then why do they have to mix it on-site? Is it simply because of the sheer amount of flash required to produce a supersonic concussion effect?

Does anyone know how many grams of flash is used in concussion shells?

[Mortartube]

I think we are at cross purposes here. It is mixed on site to be used in concussion mortars as a ground effect.

Aerial maroons are pre-manufactured and let off as supplied. They are effectively a shell containing only flashpowder to produce loud report.

A 3" aerial maroon may contain less than 20g of flash and still produce a huge sound and have a devastating effect destruction wise if misused.

I would suggest that you pursue other things such as BP first. I know that it is interesting to find out about flash but it is unforgiving. You only make one mistake with it.

I still cringe at the thought of handling it and I worked in a firework factory over a period of 8 years.

There is more skill (and in my book satisfaction) in making a lovely deep blue star than there ever will be in loud bangs, Any fool can do it and many have died trying.