38 replies to this topic

[superspud]

Hi, for a film I am involved in making, we need a shot of a smoking bullet case. Ive got the bullet case, i just need the smoke.

Any ideas on how i could make it smoke, any chemicals or powders i could use?

Thanks.

[sizzle]

This has already been mentioned in the forums, But I shall tell you anyway.

There are several compositions used to make smoke, some are better than others but it is best to experiment by yourself and find which you think is best. Below are all for White Smoke.

I tend to use:

Potassium Nitrate.............6
Sugar..............................4

There is also:

Potassium Nitrate..............48.5
Sulphur..............................48.5
Reagar............................3

I am guessing however you are not looking for hundreds of litres of smoke eminating from the bullet so I don't know what to suggest, maybe just using a gram of Compostition one (Sugar/Potassium Nitrate) inside the case would do? as for detonation I leave that up to you, I have no idea how it can be done apart from e-match.

Edited by sizzle, 17 October 2005 - 03:23 PM.

[superspud]

( the D word )

I can try, i tried boiling sulphur in the case then blowing out the flame and letting it fizzle... it worked ok but the smoke was quite thin

[sizzle]

Well I can tell you from experience Potassium Nitrate and Sugar gives a nice thick flowing smoke.

[superspud]

(just tried it)

yeah, it does BUT it burns very quickly... can i slow the process down at all? what if i made a pellet of teh compound?

Thanks.

[sizzle]

I think a Sulphur/Sugar/Potassium Nitrate mix may be slower buring, compressing into a pellet would certainly slow it down.

[superspud]

Hi, what ratios of the chemcals is needed for that>

Thanks for your help

[sizzle]

I don't know for definate but try:

Potassium Nitrate........6
Sugar........................4
Sulphur.....................2

If that doesn't work too well try experimenting yourself with the chemicals, you'll eventually find a ratio that suits your purpose.

[Frozentech]

Hi, what ratios of the chemcals is needed for that>

Thanks for your help

50/50 KNO3 and sugar, can be melted together over low heat ( search the web, lots of examples) if powdered isn't working for you. I may have missed this in an earlier post, but you did want *white* smoke, yes ?

[alany]

Boil some glycerine in the shell casing, that should work nicely.

[Erwin]

Need the case be laying on the ground and smoke? then maiby a little piece os dry ice(CO2) wil work, but the smoke(CO2) is heavier then air.

[adamw]

Maybe as others have suggested, a chemical smoke is more appropriate (look up on the 'net' some glycerine + x x x mixes). Plus, for realism's sake you wont want billowing smoke and sparks etc. A round of nitro ammunition isn't completely 'smokeless' but a wisp of translucent white smoke is realistic.

This thread will be moved into SFX

[RegimentalPyro]

Hmm - Doesn't ammonia and Hydrocloric Acid vapour produce just this sort of smoke? Ammonium Chloride particles precipitating into the air if I remember right.

As I recall the reaction is very easy to do. Just bringing the stoppers of the chem bottles together produced the "smoke"

[Richard H]

Yes indeed, I remember that from my school days!

[Frozentech]

Hmm - Doesn't ammonia and Hydrocloric Acid vapour produce just this sort of smoke? Ammonium Chloride particles precipitating into the air if I remember right.

As I recall the reaction is very easy to do. Just bringing the stoppers of the chem bottles together produced the "smoke"

Now, that sounds like the solution to his problem.

It also reminds me of an odd "experiment" I did when I was about 10 or 11, and lived in Texas. I had obtained some strong Ammonium Hydroxide solution from my father (who was into chemistry and pyro also ), and while messing around with a large mounded nest of red ants, decided to try and poison the nest with it. This was a 1 1/2 foot tall mound, which seethed with ants. I had already discovered that when they were disturbed, the air above the nest was filled with acid mist (formic acid ?) which you could smell, and would sting cuts and scratches on your skin... anyway, to make it short... a similar reaction occurs when thousands of pissed off red ants are bathed in NH4OH, and they *smoke*.