In article ,
Don Foreman wrote:

On Thu, 04 Mar 2010 21:26:15 -0800, Larry Jaques
wrote:

On Thu, 4 Mar 2010 04:44:57 -0800 (PST), the infamous Jim Wilkins
scrawled the following:

On Mar 4, 7:17*am, Larry Jaques wrote:
...
I missed the first part of this thread. What are these things for? It
looks like a propane-to-rattle-can adapter, maybe used to repressurize
flat spray cans.

Makes them round again.

If propane doesn't quickly dissolve into the contents it can
overpressure the can, that's why I used butane.
http://www.engineeringtoolbox.com/pr...re-d_1020.html

Spray cans do not fail gracefully. I'd rather not post the details as
others might try and not be so lucky.

Ouch! Scratch that off my list of possible cool tools to have/make.

And you gave me **** about shying from a 40-joule ICD mulekick when
TIG welding, you macho devil-may-care dawg!

Not knocking prudence, caution and dainty demurral, but note: it
takes about 150 PSIG to pop a plastic (PET) beverage bottle. Metal
cans are smaller and stronger than plastic bottles.

I don't know if dissolution into content lowers vapor pressure or not,
and if so what the time constant might be, I'll defer to Wilkins on
chemistry.

Dissolution has no effect on vapor pressure whatsoever.

More generally, if you take each ingredient and put it alone in the can and
measure the pressure one by one, all at the same pressure, the pressure of the
mixture is the sum of the individual partial pressures.

This is called Dalton's Law of Partial Pressures.

http://en.wikipedia.org/wiki/Dalton%27s_law


Joe Gwinn