"Bob Engelhardt" wrote in message
...
On 11/12/2014 3:34 PM, Larry Kraus wrote:
Depress nozzle on can, apply rubber tipped blow gun and add
compressed
air. Done.


The advantage of propane is that it's liquid and maintains a
constant pressure that is its vapor pressure. Until the very end,
of course. With air, or any gas, the pressure will decrease as it's
used.

Bob

The disadvantage is that its pressure depends on how well it dissolves
in the liquid in the can, and the relative quantities of product and
propane which you can't easily determine or control.
http://en.wikipedia.org/wiki/Raoult's_law
"If a non-volatile solute (zero vapor pressure, does not evaporate) is
dissolved into a solvent to form an ideal solution, the vapor pressure
of the final solution will be lower than that of the pure solvent."

If it doesn't dissolve the pressure may exceed 200 PSI.
http://www.engineeringtoolbox.com/pr...re-d_1020.html

-jsw