Chemical Forums
Specialty Chemistry Forums => Citizen Chemist => Topic started by: dubfunkstar on May 10, 2005, 07:01:42 PM
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Okay guys I am on a pianyball team and we use smoke grenades..but since they create great heat we have found that they arent aloud on some fields...well most all fields for sbvious reasons..so that is why I am here asking all of you how to make a heatless smoke device...If you have any question about the ethics of me asking this I will also provide my teams web addy....
http://www.teamimpactpb.com
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That would be pretty difficult to do for numerous reasons. One is that smoke is just a mixture of small particles of solid carries by a gas. In order to generate that gas over a long period of time, you need to generate it from a chemical reaction. Chemical reactions that generate gas are exothermic and will put out a good deal of heat. Smoke is tiny little particles of ash and carbon which are distributed through the air thanks to the expanding air coming off of a fire.
One thing which MIGHT work would be if you had some pressurized gas and a fine smoke particulate/dust. You could then set the device off and the pressurized gas would "slowly" escape and carry the smokedust with it, thus making a smoke filled area. (It would be best to use some ashes from a charcoal grill or a fie as they will not have the potential to combust like many fine powders can). The only problem with this device is finding a way to let out gas from the pressurized container at a constant rate and 'safely'.
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This is actually a common thread on rec.pyrotechnics, almost always used for paintball. Jdurg is right, too, it's going to be difficult to find a way to make a heatless, non-toxic smoke grenade. I mean, you could use TiCl4 in a glass vial and then smash it--it definitely does the job for smoke--but the 'smoke' is HCl vapor. Not something you want on the field. So, yeah, it's not easy. Perhaps you could use some dry ice in water, but that'd be something that provides minimal 'smoke' effect and usable only near a stationary place.
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In addition, you'd need to keep the water and dry ice completely separate until you want to fog to form, and you'd also need to keep the dry ice cold and vented. Putting dry ice and water into a confined space will result in a lot of shrapnel and people getting hurt.
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Well, I can name a whole bunch of formulas for smoke compositions, but I've only tried one: The traditional saltpeter and sugar formula. In all likeliness, this is what is used in paintball smoke grenades (I know that many people make their own using this formula). However, it does create a rather large quantity of heat; certainly enough to, say, light some underbrush on fire. Like I said, I can name several compositions from a list that I have, but none of them are called "low heat" or anything like that, and I haven't made or tested any of them.
My suggestion to you is to either:
1) find a way to contain the heat from the saltpeter/sugar reaction (in either a 40/60 or 50/50 ratio by weight [edited] ), or in some other way stop the grenade from starting a fire. I was thinking about this a little while ago, and I came up with the idea to cast the composition into an empty soda can, then wedge the can into a spring from an old sofa. Because the springs are somewhat hyperbolic, they would keep the can at least an inch or two off the ground. I never tested it, but it might work...
2) If you really wanted to, you could try out the formulas I have. However, they call for pretty obscure chemicals, which probably would cost a lot. There's also no guarentee that any would work.
3) look some more. Presumably, since the formation of gas is favored in terms of entropy, there must be a reaction out there that is not significantly exothermic. After all, if entropy is favored there is no need for a very negative delta H number.
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if heat must be produced, why not put it on a bed of bricks, surround the mixture with a wall of bricks , and set it off?
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Like MrBigglesworth said put in bricks. Just look for a formula for a clay ceramic that will withstand the combustion and just drill a whole in your ball/canister, fill with your reactants, stick a fuse in, and light. The ceramic type material will help contain heat, but if your whole isn't big enough you'll have just created an explosive in a sense. You'll still have to worry about heat from your whole, but with the little fireworks smoke things I buy for the 4th th gas usually pushes the ball up right (whole up) and it stays there. Alternatively use cement.
P.S. If you try any of this, test it out somewhere where nothing will catch fire and from a safe distance. Hope I helped a little.
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remember, he wants this so he can use it during a paintball match. Having the thing in a huge box made of bricks can't possibly be practical. If I were you, I'd someone with a lot of experience dealing with pyrotechnics. You could try asking the people from places like skylighter.com or unitednuclear.com, who are suppliers to the pyrotechnics community, if they have any compositions they could suggest.
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Sorry there, Corvetteaholic, a slight part of your procedure can be reasonably dangerous, so I took the liberty of editing it out. The smoke grenade you talk about is the common potassium nitrate/sugar mix for making smoke bombs. It's pretty good, although it is just white smoke, and it produces one hell of a lot of heat. Fire, actually. It is completely effective and not very dangerous to simply mix the potassium nitrate and sugar together manually (i.e., just shaking the ingredients in a paper bag or something). There is a very slight chance that grinding in a mortar would light it on fire, so I'd recommend doing that outside if you are interested in doing that, but it should be pretty safe. I make smoke bombs with this stuff, and it's a lot of fun. I have a friend who probably shares a lot of Limpet's 'tastes' and I hand him a small sheet of paper and a pile of this powder, and he rolls it up into a small cylinder, then we set it in the yard and light it on fire. He's really good at what he does, so we wind up with some pretty tight smoke bomb rolls. :)
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What about, a device that would combine some highly concentrated ammonia solution, and HCl, that gives off white fumes of ammonium chloride.
HMX, actually, I am not that mucn into pyro stuff really, I do the very occasional thing, such as thermites to prepare pure metals in my lab, and the odd experiment into primary explosives, I mainly do organic actually myself.
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Limpet, I think you missed my point... my friend rolls up smoke bombs as if they were joints. :) They make good smoke bombs, too. He's not a pyro, either. He just knows how to roll joints, something I am completely inept at doing, lacking experience.
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Just look for a formula for a clay ceramic that will withstand the combustion and just drill a whole in your ball/canister, fill with your reactants, stick a fuse in, and light. The ceramic type material will help contain heat, but if your whole isn't big enough you'll have just created an explosive in a sense. You'll still have to worry about heat from your whole, but with the little fireworks smoke things I buy for the 4th th gas usually pushes the ball up right (whole up) and it stays there. Alternatively use cement.
I think this is a good idea because, like constant thinker said, ceramic or cement WOULD be heat resistant. You could even make a can you could open and just put the smoke grenade inside it. It would take any chemistry out of it though. ;D
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See someone understood what I meant. You just need a small case made of a thermal insulator. Ceramics and cement don't need to be thick to provide good insulation. You may be able to buy other materials that wicked light and wicked good at insulating heat.
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What about, a device that would combine some highly concentrated ammonia solution, and HCl, that gives off white fumes of ammonium chloride.
HMX, actually, I am not that mucn into pyro stuff really, I do the very occasional thing, such as thermites to prepare pure metals in my lab, and the odd experiment into primary explosives, I mainly do organic actually myself.
This is something that I'm rather interested in, too, for the purposes of research in my job. I'm trying to find a way to generate smoke for testing thermal plumes from a small heating block. I've tried using HCl and Amm. but either my solutions aren't concentrated enough or I'm not using enough. I can (accidently) get the reaction going on my gloves, though its short lived and not particularly impressive. At the moment I'm using two small test tubes with cotton wool wicks side by side on the hot plate (which is about 3" x 1" an runs about 40oC) but to no avail.
I'm really hoping that there is an alternative (TiCl4 is right out due to the horrible mess it tends to leave behind and its toxicity) as are smoke matches (make their own plumes). Equally CO2 isn't of any use because of the way it sinks to ground level.
Apologies for tagging this onto someone elses topic, it seemed relavent and a bit of a waste to start a new one. Thanks for any advice.
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When I picture asmoke grenade...I picture throwing a thing, and it explodes in a plume of smoke...instantly. Perhaps this is not what you want...but if you're looking for just BOOM and then there's a huge plume of smoke, then look into the reaction that's used to rapidly fill airbags...I think Sodium azide (NaN2) undergoes a reaction to give off a LOT of N2 very fast, and this could be used.
Only problem is that N2 is denser than the rest of 'air' - so it will float to the ground and stay there -- not ideal if you have your people crawling across the field on their fronts...breathing in a lot of N2....
But give it some thought ;D
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well... nitrogen doesnt seem to be smoky to me... we can see through 78% N2 after all :P
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hey, i just disected some fire crackers. I read that the white powder was KNO3, this makes sense because there needs to be oxygen for flame and this gives off oxygen. Well i mixed it with some sugar, about 1:1 in amount. I then made it into a paste with a couple drops of water, and i then proceded to pack into a straw, not very easy to do. I tried to slowly suck it up the straw. no good, good thing i didnt make much. Is that stuff bad for you :)?? i flushed my toung, so it couldnt have done any thing. I hope it turns out, i want to do the dangerous method and make a metal shell to insert rods into and it have an igniter, but i think it'll burn up!
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well, you HAVE to let it COMPLETELY dry out, all i managed to do with one of mine was to <i>make</i> the dangerous stuff cause it was melting it and its shell. I am waiting for my second to dry...
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Well, I lived in china for a year... I remember them making some kinda smoke bomb. Just take a ping pong ball, tear it into little bits, and wrap it well in napkin and ignite it. It burns kinda slowly, and makes a lot of smoke... You could probably put a rock in it to throw it greater distances.
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Just take a ping pong ball, tear it into little bits, and wrap it well in napkin and ignite it. It burns kinda slowly, and makes a lot of smoke...
Not every ping-pong ball, celluloid one, if they are still made - most balls I have seen lately were from some other plastic. And be carefull, as celluloid burns fast. Trick is to keep it in something closed so that there is no free air flow. Only then you will get the smoke.
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It had worked ok. It filled a whole guard shack in about 10 seconds. Do you mean the tighter you wrap it, the more smoke?
(How do you know all this stuff?)
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The smoke grenades used in paintball fields consist of potassium chlorate a fuel and hexamine. Hexamine greatly reduces heat output, while potassium chlorate tends to burn cooler anyway.
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When I picture asmoke grenade...I picture throwing a thing, and it explodes in a plume of smoke...instantly. Perhaps this is not what you want...but if you're looking for just BOOM and then there's a huge plume of smoke, then look into the reaction that's used to rapidly fill airbags...I think Sodium azide (NaN2) undergoes a reaction to give off a LOT of N2 very fast, and this could be used.
Only problem is that N2 is denser than the rest of 'air' - so it will float to the ground and stay there -- not ideal if you have your people crawling across the field on their fronts...breathing in a lot of N2....
But give it some thought ;D
Except sodium azide is unstable and decomposes easily with shock. In addition, sodium metal is also generated which reacts and could cause fires and burns.
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Sodium azide is just another toxic lab reagent. The conditions for it to decompose energetically are not going to be accidentally achieved.
For the original question, why not rig up something to puncture a CO2 cartridge for airguns, and allow the escaping CO2 to disperse some flour or something.
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I know that it has to be possible in some respects to make a cold smoke bomb. However a nontoxic one of those seems unlikely since most nontoxic elements are completely see through. I really liked the insulation idea with one small tweak to the design. Instead of hoping the ball would roll straight up, why not craft a reusable shell which houses a lead weight at the bottom of a sphere? If all goes according to plan, it should spring straight up to deliver the smoke in the desired manner.
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Sorry for bumbing an old thread but there where some questions left unanswered,,,,,
What would the "perfect" mix of potassium chlorate and hexamine be? :P
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Sorry for bumbing an old thread but there where some questions left unanswered,,,,,
What would the "perfect" mix of potassium chlorate and hexamine be? :P
Even if someone will post it, the answer will be deleted according to forum rules (http://www.chemicalforums.com/index.php?topic=33740.0).
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My apology
I will immediately read up on the rules!
Is it aloud to pm such information?
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As far as I know nobody here deals with pyrotechnics (doesn't mean it was always this way, we had moderator doing PhD in explosives :) ) so I doubt you will get any answers.
No idea how it works now, but I have heard one may find a lot of good information in archives of rec.pyrotechnics (google them).
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There are many Internet sites that deal with pyrotechnics