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Topic: Help, smoke grenade proportions  (Read 10249 times)

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Offline marcel

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Help, smoke grenade proportions
« on: November 12, 2006, 04:17:45 PM »
So sorry to make another smoke grenade thread but i didn't want to revive an old thread. I'm trying to make some smoke nades for my cousins birthday(trust me he'll like them) in a week. I don't have a digital scale or the money for what they go for around here, and don't have time to order one off ebay. Please help em with some measurements. I know that the recipe calls for a 60:40 ratio by weight but i cant weight it that accurately at all. I suck at guessing weight. It would be really great if someone could please tell me what they would be by volume. I have potassium nitrate from some stump remover from Home depot and powdered sugar from the local grocers. I have been trying to figure out the proportions by spoons and so far i have only been able to make it smoke a little very fast. The ones i am rolling are lasting only about some 3 seconds or so and aren't making a lot of smoke. The only thing I'm going on is the relative size of the 2lb bag of sugar and the 1lb can of stump remover. Besides that i have been winging it. Any help is greatly appreciated and I'll be sure to post pics and videos/what not to help anyone else in my situation.

Offline woelen

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Re: Help, smoke grenade proportions
« Reply #1 on: November 12, 2006, 04:41:27 PM »
A much better source of (virtually non-toxic) smoke is to use ammonium chloride, NH4Cl, and sparklers. Take a little tube, thin cardboard is best, put in some previously dried ammonium chloride (also called salmiac), and stick in three sparklers, next to each other, with the tip just sticking out of the ammonium chloride, such that they can be lit easily. When you ignite the sparklers, they will evaporate the NH4Cl, which immediately resublimes and gives an intensely thick white cloud of smoke. Prepare the smoke bombs a short time before using them and store them in a well-sealed plastic bag. They attract humid from air.

The attractive thing of this smoke "bomb" is that the smoke is non-toxic, or only marginally toxic, when inhaled in not too large quantities. NH4Cl also is an important constituent of many sweets, hence its relative non-toxic properties.

Even denser smoke is obtained by using thin PVC tubes with ammonium chloride and sparklers, but I do advice against those, because of the intensely toxic fumes, coming from the decomposing PVC. I would stick to thin cardboard.
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Offline hmx9123

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Re: Help, smoke grenade proportions
« Reply #2 on: November 12, 2006, 05:11:47 PM »
Try using a 1:1 ratio of potassium nitrate to sugar by volume.  That always seemed to do OK.  Remember that you're looking for a fuel rich composition to emit smoke, but not so fuel rich that it won't burn.

Offline marcel

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Re: Help, smoke grenade proportions
« Reply #3 on: November 12, 2006, 10:59:52 PM »
Thanks, will try the 1:1 in the morning. As far as NH4Cl and sparklers, I'll have to go shopping on ebay. Would you recommend that over the KNO3 and sucrose? For quantity of smoke to volume of material?

Offline marcel

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Re: Help, smoke grenade proportions
« Reply #4 on: November 13, 2006, 09:47:05 PM »
OK, that didn't work quite as i planed. The 1:1 volume mixture lightly packed in paper caused about a 1-2 second burst and almost rocket like effect. It moved a good 3 feet in on direction and then stuttered a little. Not a whole lot of smoke was produced. The size of the test was about 2 inches long and one half or less inch wide. I used a fuse from an old firecracker. What sort of increment should i use to adjust it by and what should i increase is my next question. Any help is much appreciated.

EDIT: I just tried a version tightly packed in thick paper, in 1:1 proportion by volume. It almost flew off, but it made more smoke than the other version. It burned in about 4 or so seconds. I'm guessing that i need more sucrose but that is just my guess. Please help me with this i need to have something for this upcoming weekend. Thanks in advanced.
« Last Edit: November 13, 2006, 10:41:03 PM by marcel »

Offline hmx9123

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Re: Help, smoke grenade proportions
« Reply #5 on: November 14, 2006, 03:18:09 AM »
Don't try to rush things.  It's a terrible idea with chemistry and an even worse idea with pyrotechnics and energetic materials.  I'm very close to locking this thread because it seems like it's going in the wrong direction.  Be safe, don't be stupid, and don't use this stuff at a party.  Go buy a real smoke grenade or some smoke bombs from your local fireworks stand.  Your brother deserves that and doesn't deserve to get his face burned off.  You can get a pack of 6-10 smoke bombs for less than $3.  They even come in colors.
« Last Edit: November 14, 2006, 03:23:52 AM by hmx9123 »

Offline marcel

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Re: Help, smoke grenade proportions
« Reply #6 on: November 15, 2006, 01:53:58 AM »
I'm just asking for some help with the proportions, were not planning on using this for his birthday with all sorts of people there or anything. I just can't figure out what i should increase or decrease get more smoke from this and a longer burning mixture. I'm just getting puffs of smoke that are clearly see-through. I realize this may seem like a strange gift idea but he has talked about wanting to make these for a while with no luck. I was just trying to basically make some for him and tell him how and where to get the chemicals. Kinda a learning experience thing. I know that he will really like this gift, the premade smoke grenades your talking about are really expensive here when it isn't round the holiday they are used at. Seeing as it is dry here a lot there is usually a burn ban so getting these is extremely difficult. Thanks for your help but i just want to know if i should increase the sugar or KNO3 to achieve the effect i want. Thanks again for all the help so far, i have until this Saturday to make a usable mixture, if i can.

Offline woelen

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Re: Help, smoke grenade proportions
« Reply #7 on: November 15, 2006, 04:48:11 AM »
Try adding more sugar. The mix should smoulder, not burn fiercely. Smouldering makes it more slow and longer lasting and gives more smoke. But if you have too much sugar, then it does not burn anymore. So, use as much as possible of sugar, but still assure that it is a sure fire and it does not stop burning/smouldering.
Want to wonder? See http://www.oelen.net/science

Offline marcel

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Re: Help, smoke grenade proportions
« Reply #8 on: November 15, 2006, 04:49:55 AM »
Thanks a lot! I will try in the moring.

Offline hmx9123

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Re: Help, smoke grenade proportions
« Reply #9 on: November 16, 2006, 03:34:57 AM »
You should do a lot of background reading on rec.pyrotechnics.  They have a tremendous amount of material on smoke devices.

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