Looking for a substance that can be use as a heat barrier 1

[hotlz]

Hi

I am looking to in case a copper pipe within another pipe of larger dia. I'm looking for a material or substance that is cheap and easy to attain that will reduce heat transfer to the point that it will not catch grass or leaves a fire that the pipe may be placed on. The inside pipe will contain sugar and KNO3, burning at temp along lines of most smokeless gun powders with the same flash producing a smoke.

 

[MikeHalloran]

I am intimately familiar with the reaction to which you allude.

[ It is not possible to caramelize five lbs. of sugar/KNO3 mix in an electric frying pan without setting it off. The fellow who talked me into trying it had never gotten above two lbs. himself, but he forgot to mention that detail. ]

Unconstrained by a pipe, the reaction proceeds to completion in much less time than it takes to write about it, produces a beautiful huge purple flame, and fills a large building with dense white smoke in a heartbeat. Okay, two heartbeats.

Constrained in a pipe, well, you won't see the flash unless the pipe ruptures, and the evolving gas has to produce a pretty good pressure, so there is some risk of that happening.

So, you want to fill a pipe with this mix, start the reaction, toss your device in leaves/ grass, and NOT start a fire? What, pray tell, ARE you trying to do?



Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[hotlz]

Thanks for the info on trying to melt more than two pounds. I only tried a mix of 30g to 20g that worked out very well. The reason for the question is that I play paintball and need a good cheap smoke and this stuff would work great but it burns hot and I would like to reduce the chance of it starting a brush fire.

My idea is to have a core pipe of 1" dia with one end sealed and this is where the material that creates the smoke is. The other end will be open and this is where the fuse goes and where the smoke can escape. On the outside of this tube, I'd like to have something around the outside to reduce the heat transfer to the outside pipe of 1 1/2" dia. I was thinking of clay????

***Anyone know how clay would work or any other item that would work?

 

[ivymike]

Have you tried concentric metal cylinders with air in between?

 

[hotlz]

I thought about that, but there still would need to be spacers between the cylinders and would the spacers transfer to much heat to the outside cylinder? I also thought of using firework paper tube put inside of metal cylinder but not sure if this would let the metal get so hot that it would cause grass, dead leaves to combust into flames do to heat from the metal. Not so worried about flame for that will be inside of the tube.

 

[JimCasey]

I suppose you know that there is a substantial danger of explosion. What you are describing would be a pipe bomb and the local/Federal/planetary authorities would be humorless in dealing with you if you are discovered with it in your posession. If you DO set it off, it could send sharp shards of hot copper which could effectively or literally remove you and your companions from the gene pool.

Don't do it.

If you feel the need for pyrotechnic smoke, visit your local fireworks stand. They wrap fireworks in cardboard tubes for a reason.

 

[unclesyd]

I second the post of MikeHalloran and JimCasey[/] stay away form this reaction.

I think they still sell smoke bombs. Look around for the best price.

Try your local marine supplier. We have several on our boat.

Also try the local utilities company and see if they use smoke bombs.

We used smoke bombs in tracing and mapping drain lines.