"Bob Engelhardt" wrote in message
...
On 11/13/2014 4:13 PM, Bob La Londe wrote:

That holds true with C02 as well, but pressure does fluctuate with
temperature.

Well, yeah but ... the vapor pressure of CO2 at room temperature is
about 900 psi, IIRC. Whereas for propane it's 100 psi, again IIRC.


The vapor pressure of CO2 dissolved in soda water is much lower, as is
that of acetylene dissolved in acetone. Unless you make a connecting
hose with a pressure gauge and shutoff valve you don't know how much
pressure the can should have, or how much you are adding.

When I did this in college I tested the pressure by denting the can
with my thumb, which I can just barely do at the original factory
pressure. I used a little fitting that jammed into the stem of one can
and sealed with a taper in the stem of the other, and pressed them
together with the butane on top.