making stuff explode

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bocochoco
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making stuff explode

Postby bocochoco » Mon Oct 26, 2009 7:22 pm UTC

Title says it all. I've been using a mixture of carbon, potassium nitrate, and sulfur milled into a gray powder, but it makes a lot of fire rather than the explosion i'm looking for. Note that this is for academic purposes. My lab partner and I are working on our lab project, which involves explosives. We're not working with huge amounts here, but even with 50 grams of the mixture above we got nothing more than a rather large fireball and a lot of smoke. Any of you know of something with a bit more of an initial blast, preferably something that can be made without much difficulty.
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Re: making stuff explode

Postby whereswalden90 » Mon Oct 26, 2009 8:15 pm UTC

Don't you need to compress it to get an explosion? I know that's how it works for gunpowder at least.
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Josephine
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Re: making stuff explode

Postby Josephine » Mon Oct 26, 2009 8:18 pm UTC

yeah, low explosives like that need compression to explode. they're really just strong and fast flames.
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bocochoco
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Re: making stuff explode

Postby bocochoco » Mon Oct 26, 2009 8:31 pm UTC

So what would work best for compressing it?
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Jorpho
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Re: making stuff explode

Postby Jorpho » Mon Oct 26, 2009 8:58 pm UTC

bocochoco wrote:Title says it all. I've been using a mixture of carbon, potassium nitrate, and sulfur milled into a gray powder, but it makes a lot of fire rather than the explosion i'm looking for. Note that this is for academic purposes. My lab partner and I are working on our lab project, which involves explosives. We're not working with huge amounts here, but even with 50 grams of the mixture above we got nothing more than a rather large fireball and a lot of smoke. Any of you know of something with a bit more of an initial blast, preferably something that can be made without much difficulty.
Do you have the right proportions? As I dimly recall (from Napoleon's Buttons), 70% potassium nitrate is about right.

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bocochoco
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Re: making stuff explode

Postby bocochoco » Mon Oct 26, 2009 9:01 pm UTC

Jorpho wrote:
bocochoco wrote:Title says it all. I've been using a mixture of carbon, potassium nitrate, and sulfur milled into a gray powder, but it makes a lot of fire rather than the explosion i'm looking for. Note that this is for academic purposes. My lab partner and I are working on our lab project, which involves explosives. We're not working with huge amounts here, but even with 50 grams of the mixture above we got nothing more than a rather large fireball and a lot of smoke. Any of you know of something with a bit more of an initial blast, preferably something that can be made without much difficulty.
Do you have the right proportions? As I dimly recall (from Napoleon's Buttons), 70% potassium nitrate is about right.


Yup 70% nitrate, 20% carbon, 10% sulfur.
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whereswalden90
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Re: making stuff explode

Postby whereswalden90 » Tue Oct 27, 2009 1:33 am UTC

The tough part will be getting a good explosion without making shrapnel. My first thought was to put the powder in a breakable ceramic container, but that would most certainly create shrapnel. I wonder if it would be possible to use paper?

EDIT: just had a thought: DUCT TAPE!
Last edited by whereswalden90 on Tue Oct 27, 2009 1:41 am UTC, edited 1 time in total.
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Re: making stuff explode

Postby whereswalden90 » Tue Oct 27, 2009 1:35 am UTC

bocochoco wrote:
Jorpho wrote:
bocochoco wrote:Title says it all. I've been using a mixture of carbon, potassium nitrate, and sulfur milled into a gray powder, but it makes a lot of fire rather than the explosion i'm looking for. Note that this is for academic purposes. My lab partner and I are working on our lab project, which involves explosives. We're not working with huge amounts here, but even with 50 grams of the mixture above we got nothing more than a rather large fireball and a lot of smoke. Any of you know of something with a bit more of an initial blast, preferably something that can be made without much difficulty.
Do you have the right proportions? As I dimly recall (from Napoleon's Buttons), 70% potassium nitrate is about right.


Yup 70% nitrate, 20% carbon, 10% sulfur.

Huh. Wikipedia says 75% potassium nitrate, 15% softwood charcoal, and 10% sulfur.
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Tass
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Re: making stuff explode

Postby Tass » Tue Oct 27, 2009 8:14 am UTC

Rather than compression I would call it containment. You do not need to compress it before igniting, simply have it in a closed container.

Any thing will work, the more tightly sealed and the tougher the container the better. Duct tape or a plastic film canister will give you a sizeable poof. A soda bottle will give you a rather dangerous explosion. A steel pipe with closed ends will give you a lethal weapon.

BE CAREFUL! While 50 grams of gunpowder in the open will just give you a small fireball, a FEW GRAMS can be LETHAL under the right circumstances. Don't make a pipebomb.

There are modern high explosives (nitroglycerin was one of the first discovered) that burn fast enough that they have no time to dissipate and all their force are delivered at once. They are called brisant from french for "shattering". They don't need containment. Gunpowder is not one of them.

What happens when you contain gunpowder is in part that it simply allows a physical explosion. The gunpowder builds up pressure until the container breaks, releasing it at once. You can even use steam for this kind of explosions, and they can be rather bad. Another part is that as the first gunpowder is ignited, it increases the temperature and pressure in the container, causing the rest of the gunpowder to burn faster, making a runaway process. Even when the container breaks, the powder is now so compressed and hot that it behaves much more like the brisant explosives, so the container simply don't "have time to finish breaking" before most have reacted.

heydonms
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Re: making stuff explode

Postby heydonms » Tue Oct 27, 2009 8:15 am UTC

I suspect there are a few areas where you need to make changes.

I can offer some advice on improving your powder as well as a few resources you might want to have a look at, PM me with more details of what you are trying to achieve and the methods you are using.

I don't want missing limbs on my conscience so I'm not going to post instructions here.

Ieatsoap6
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Re: making stuff explode

Postby Ieatsoap6 » Wed Oct 28, 2009 6:00 am UTC

The easiest way to get something that probably* won't kill you, but will be more explosion that small puff of smoke, is a trick I learned in my "messing around with fire" days. Take a normal drinking straw and cut off about one inch of it. Take that (one inch) piece and using a hot glue gun, seal off one end. Let it cool and then put your mixture inside. Then get a fuse, such as from a firecracker, stick it a bit into the powder, and use the hot glue gun to seal off the other end of the straw bit. Let it cool and then it's ready to go.

The basic principle here is compression as others have mentioned. Essentially what this is is a small firework/cracker. The straw will compress the gases enough to make a _pop_ but not enough to be dangerous*.

I don't actually remember if I tried this with black powder, but it definitely worked well for another mixture of similar characteristics.

*That doesn't mean you should hold on to it when it's about to explode. Practice basic safety around this since it can still do substantial damage if done incorrectly.

Mr. Freeman
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Re: making stuff explode

Postby Mr. Freeman » Wed Oct 28, 2009 6:19 am UTC

bocochoco wrote:Any of you know of something with a bit more of an initial blast, preferably something that can be made without much difficulty.


Nitrogen triiodide. Mix ammonia and iodine, wait a few minutes, decant, and the powder left over is something quite amazing. Amazingly sensitive but releases a relatively huge amount of energy. It looks like an exploding purple powder. Just be sure not to inhale the fumes, it's iodine and isn't the best thing to breathe in.

Do some research before you actually do this though, it isn't something that you should do improperly informed.

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Jorpho
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Re: making stuff explode

Postby Jorpho » Wed Oct 28, 2009 3:54 pm UTC

Mr. Freeman wrote:Nitrogen triiodide. Mix ammonia and iodine, wait a few minutes, decant, and the powder left over is something quite amazing. Amazingly sensitive but releases a relatively huge amount of energy. It looks like an exploding purple powder. Just be sure not to inhale the fumes, it's iodine and isn't the best thing to breathe in.
I've heard a lot about that, but was never clear on the preparation. I had no idea it was so simple. Plain old crystalline iodine, eh? (Can you make that from tincture of iodine?)


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