Chuck wrote:
> Shoot a little propane in the system and enjoy -
>

It's not perfect but it'll work. IIRC, the oil in a R12 system is
correct for propane too.. It's been a while since I looked into it.. Oh,
I remember, I think- the vapor pressure is too high, adding 30%
isobutane brings it right into line. I've heard that isobutane can be
found as high-altitude campstove gas.

If you were to do it, which I believe is a federal crime, I think it
would be better to use the small bottles for torches/lanterns as I don't
think they have the stinky chemical in them.. that will contaminate the
oil and shorten the life of the system.

Propane is a direct replacement for R22- virtually identical pressure
curves and, again, the oil is compatible.

Anhydrous ammonia is another candidate. I am unaware of legal
complications with anhydrous, as with all things bragging without proper
learning is contraindicated.