Interesting idea for foam explosive

[xyz]

Yesterday I was thinking about a demonstration that my Chemistry teacher did a while ago where he put a small amount of 30% H2O2 in the bottom of a graduated cylinder, added a squirt of dishwashing liquid, and then dumped a teaspoonful of Potassium Dichromate into the mixture. In a few seconds there was a column of foam made from oxygen bubbles pouring out of the top of the cylinder.

I was thinking that you could take some conc. H2O2 and add dishwashing liquid to it, then add a suitable catalyst and some Calcium Carbide so that you soon had a lot of foam made from Oxygen/Acetylene pouring all over the place <img border="0" title="" alt="[Wink]" src="wink.gif" /> . You would then ignite the foam when no more was being produced.

This could be scaled up to fill a room with explosive foam as it produces many times it's volume in foam. If you used KMnO4 as your catalyst then you could add Glycerine to the H2O2 so that ignition would occur spontaneously after the room had been filled.

I would like to try this but I am unable to get Calcium Carbide.

<small>[ January 18, 2003, 09:50 PM: Message edited by: xyz ]</small>

[nbk2000]

You could add the peroxide to the carbide, with a little rust added in to break down the peroxide, and the remaining water would decompose the carbide into acetylene. No need for permanganate.

Also, dish soap isn't the best things for long lasting bubbles. Polymeric bubble mix is better since that would retain the gas for much longer than aqueous foam would, allowing you more time to blow the gas mix.

For the most effective ignition, you'd want a small explosive charge loaded with incendiary material that'll ignite the foam from as many places at once as possible. Otherwise it may just rapidly burn, rather than violently explode.

You'd also need to figure out how to react the peroxide and carbide at the proper rates to ensure a suitably explosive mix, since you can't depend on the averaging of the two products to be the proper ration since each bubble would be like a mini-ballon of gas, each of which might have differing ratios of gas.

[xyz]

The permanganate was to catalyse the decomposition of the H2O2 and had nothing to do with the carbide, but you would mix them together and then add them to the H2O2 so that both gases started forming at the same time.

The foam in the demonstration lasted a long time without the bubbles bursting and the bubbles were very small. Isn't Glycerine supposed to make good bubbles?

It would probably be possible to alter how finely powdered the catalyst and the Calcium Carbide were so that the gas formed at the right rates.

<small>[ January 19, 2003, 02:39 AM: Message edited by: xyz ]</small>

[Genital-Warfare]

The soap holds the bubbles and the other agent, in my case, baking soda forms them, thats why they are so small.

CTR

[Zach]

"The soap holds the bubbles and the other agent, in my case, baking soda forms them, thats why they are so small."

I don't at all understand what you are trying to say. please clarify

[NickSG]

I might be wrong, but what he might be tring to say it becuase baking soda is being used, it doesnt produce enough gases to make the bubbles very large. Agian, I might be wrong, I am not sure.

<small>[ January 25, 2003, 08:57 PM: Message edited by: NickSG ]</small>

[VX]

xyz, good plan. However you would not be able to use the KMnO4/Glycerine to ignite the mix anyway because it would be very diluted with water, far too much so to ever cause ignition. However the addition of KMnO4 would cause purple foam, far more fun than just plain old white <img border="0" title="" alt="[Wink]" src="wink.gif" /> .

A good plan may be to use a reasonably sized HE charge to detonate the foam increasing the chances of a FAE (Detonation of the gasses) instead of a huge fireball(simple combustion). Depends on the effect that you want I suppose.

[xyz]

Genital Warfare, what has baking soda got to do with any of this?
I think you may have baking soda (sodium bicarbonate, forms bubbles of CO2 on contact with acids) confused with calcium carbide (forms bubbles of acetylene on contact with water). Know your chems!

VX, you could also have yellow foam if you use potassium dichromate as your catalyst.

<small>[ January 25, 2003, 10:53 PM: Message edited by: xyz ]</small>