$40 AC Fix, AKA getto guide to HC-12a

[Ionstorm66]

So after suffering though trying to find the leak in my system, and even harder tracking down R-12, I took the advice of a friend and converted the system to "HC-12a"

 

Now you can't get HC-12a in the states because it's flammable/dangerous, but now almost every refrigerant is flammable. HC-12a is about 90/10 Propane/Butane, so I used normal propane gas and "Coleman" gas which is 80/20 butane propane.

 

Called a AC guy to recover the R-12. Then held good vaccum for about an hour to get the any water or gas out.

 

Weighted them going in with a kitchen scale to get the right ratio. You only full the system to 40% of the R-12 weight, and never exceed 80 psi on the lo pressure. The sight glass will be cloudy.

 

I used a adapter from 1LB tank to 1/4 NPT and a 1/2 acme to 1/4 NPT off a old 134A adapter to hook the bottles to the system. Could fill a few cars off one set.

 

While a leak is dangerous due to flames/explosions, it's way way better for the environment. Realistically if you ever needed to work on the system you could just slowly vent it and burn the gas off. Would be perfectly safe and ok for the ozone. Also legal.

 

 

[Ionstorm66]

Forgot to mention, it is insanely cold now. HC-12a has a lower head pressure, so it's easier on the worn out compressor than R12 or especially 134a.

 

I have sub 50* air out the vents on a 90-100* day. 

 

[azdave]

I've used HC-12a for at least the last 12 years in multiple R-12 systems but now use R-152a as it is cheaper and easy to find. I can buy it by the case at Costco as it is the same thing as Dust-Off spray cans. Works fine in my old R-12 systems. Google it and you'll see it's been used in old cars for years with few concerns. No hose or oil changes needed. Drop-in substitute in my vehicles but it takes less gas than R12.

[Ionstorm66]

26 minutes ago, azdave said:

I've used HC-12a for at least the last 12 years in multiple R-12 systems but now use R-152a as it is cheaper and easy to find. I can buy it by the case at Costco as it is the same thing as Dust-Off spray cans. Works fine in my old R-12 systems. Google it and you'll see it's been used in old cars for years with few concerns. No hose or oil changes needed. Drop-in substitute in my vehicles but it takes less gas than R12.

R-152a is in-between R-134a and R-12 in pressure ranges, HC-12a is lower than even R-12, so it helps with old worn out compressors.

 

R-152a is EXTREMELY toxic when burned, and is just as flammable as HC-12a. So the only improvement is you don't have to mix it.

Edited April 28, 2022 by Ionstorm66

[azdave]

I have never worried about the flammability of any automotive refrigerant I've used. They don't ignite as easily as people think and certainly are far less dangerous than the 20-30 gallons of gasoline in my fuel tank. Some people who have complained about the dangers of using 6-8 ounces of ES-12a or HC-12a seem to forget there an thousands of motor vehicles running around with huge LP tanks onboard. Good substitute refrigerants that are banned from automotive use are due to highly paid lobbyist in our political system, not because the danger is real. Ever notice that when a refrigerant patent is about to expire a new one comes along that is freshly patented and protected from competition?

[el_freddo]

Also the concentration of the gas used as refrigerant I believe isn’t great enough to create the explosion so many fear. Sure, the whole lot in one go would make a bang but a leak, even a substantial one would dissipate too quickly for an explosion to occur. 

I haven’t read up on the ins and outs, so do your own research, take this as a prompter for that research  

Cheers 

Bennie