Re: A/C R12 retrofit
The refrigerant you are referring to is known (here in the SE) as Freeze 12. It is a drop-in replacement for R12 w/o the added hassles of an R134a conversion. Basically, it's about 87% R134a with an alternate propellant to blend with R12 oil and gas. Lots of people have dumped R134a on top of R12 w/o a problem and this is aftermarket supported evidence of that. The great thing about Freeze 12 is the low(er) price of about $9 can (was $5 retail last year) and ease of install (use adapter kit and done).
Is this stuff a good alternative to R134a conversions? Yes.
Is this stuff perfect? No.
Fact is, you still have to change over the service port fittings to accept the Freeze 12-specific install kit (fittings are included with the kit).....so add another $13-ish in addition to the cost of the freon. Just remember, that (like R134a) this stuff carries oil in the can where as R12 does not. So, it can be easy to over oil the system and turn the compressor into a hyd. pump (= not good). As with all AC service, use proper equipment and remember that freon doesn't just "wear out" over time. So, if you're blowing hot air, you not only need to recharge the system, but you need to find out why the R12 leaked out in the first place.
HTHs
Hood