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Old June 8th, 2007, 09:51   #9
Delierious Designer of Dastardly Detonations
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Join Date: Dec 2001
Location: in the dark recesses of some metal chip filled machine shop
Posted for discussion purposes only. No warranty or endorsement is implied by the following:

I'm seeing a vapour pressure of only 70PSI at a very warm 110F. Unless they made a mistake and transposed 70 with 110 (i.e. 110psi @ 70F) that's a very low pressure gas. Coleman's MSDS lists a pressure of 208psi @ 100F ( Ultrablue indicates 100% alkane content on their MSDS. I am guessing that UB is a blend of butane and propane. Propylene and MAPP are not alkanes. They would have to be indicated if they are present in significant quantity. UB's high burn temperature is probably acheived with a well designed mixer in their torch head rather than by chemical means such as an included oxidizer since none is indicated in their MSDS.

I see no indications of autoextinguishing features. There are failsafe rupture features in the can base shown in patents held by the can manufacturer:

It looks like a large piece of open cell urethane foam is put inside the can to restrict fast exhausting of the contents if the rupture feature opens.

The open cell foam would permit slow permeance of contents (exhaust to torch) but would probably bunch up at the bottom if the rupture feature were to overpressurize so the can doesn't become a rocket.

Safe and inexplosive -can is foam-filled with propane contained inside the closed foam cells
That slug of foam looks pretty open cell to me. Closed cell foam wouldn't work very well. I would end up trapping the gas so it couldn't escape to power a torch.

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Last edited by MadMax; June 8th, 2007 at 09:57..
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