Expert: George Maxwell - 7/24/2007

Question
QUESTION: i just got some potassium chlorate and aluminum powder(625 mesh)and i was trying to make flashpowder but when i put it in a tub and try to light it it wont. also i thought aluminum powder was flamable becuase i held my light to it but it wouldn't catch fire please help

ANSWER: Thanks very much for your question.

I'll answer in reverse, becuase it'll make more sense: firstly, aluminium powder is very flammable, but it needs to be dispersed as a fine dust. Holding a match to a pile of powder won't do anything, but sprinking a bit of powder in a sieve over a flame will allow it to burn quickly - explosively if confined.

Flashpowder: good stuff, but watch yourself - I've still got the scars from the second time I tried to make some!

It's important to make sure that the aluminium / chlorate are mixed, but not by using a hard implement. The usual method is to get your aluminium and chlorate on seperate sheets of paper, then tip one piece of paper on to the other and repeat, gently mixing the two powders. Before mixing, you might also want to grind up the chlorate in to a fine powder, as it normally comes in fairly big crystals.
Obviously, don't grind the chemicals once they're mixed...

Have a look on the container that the chlorate came in: some commercial sodium chlorate has a fire retardant added to stop it being used for fun chemistry!

Good luck: let me know if you need any more info.

Please excuse the laywers below:
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Legal Information:
Making explosives may be illegal in your area: check before carrying out any procedure.

Chemicals behave unpredicatably: goggles, gloves etc are a must, and even then, it's not reccomended that you carry out this procedure.

The author of this answer and the company (allexperts) accept no responsibility for the use / misuse of the information in this answer, or for any accident or injury resulting from its use - this answer is for reference only
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QUESTION: thanx alot that really helped. i have one last question if were to grind up the chlorate how could i
ANSWER: Thanks for the follow-up.

It's not too difficult to grind up chlorate, provided you don't use anything metal (nice premature bomb there).

Easy way: put the powder between two sheets of paper on a hard surface, and crush the crystals using a brick / rock (press down firmly, but don't hit hard). Take off the top piece of paper, pick up the bottom one and pour your crystals to where they need to be.

Another thought: what mixture are you using? A common one is 70% chlorate and 30% aluminium - usually people use too much aluminium.

Thanks again, hope this helps
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QUESTION: thank you some much but you got me curios what happens if you put to much aluminum powder in
ANSWER: Too much aluminium = very boring!

If you use much more than about 30% aluminium, there isn't enough oxygen (e.g. not enough chlorate) to make it burn properly, so you either get a little bit of smoke, or absolutely nothing.

Same as if you have a jar full of petrol and drop a match in it, it'll just burn, but if you take the same jar with only a spoonful of petrol and drop a match in it, it explodes, because there's enough oxygen to fully combust all the fuel.

Hope this helps, thanks for the follow up.
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QUESTION: last qeustion i sware. if i had a tube and and i wanted to fill it with flash powder how much would would i put in like half or more or does it madder


Answer
Thanks for the follow up.

You really don't want to be putting flash-powder in a tube: if confined, then as little as 10 grammes can cause a bang big enough to take off various fingers etc. The best bet is to have a small pile on an open surface (e.g. piece of wood) outside, and light with a fuse (if you haven't got a proper fuse, try a thin strip of oily rag). If you've got the recipie right, you'll get a good hot flash doing just that. Once again, though, I really don't recomend confining flash powder in any container - I can tell you from experience that it hurts! Hope this helps, and don't hesitate if you have any other questions.
Thanks