Dude, don't get so defensive just because we think you're wrong!

Seriously, I think you would benefit from digging a bit deeper below the surface. I fished my handy-dandy all refrigerants chart out from the dusty basement of my computer. Freeze 12 is a blend of three components: 59% R-134a, 39% R-124, and 2% R-600 (isobutane). I'm not familiar with refrigerant-124, but since this stuff is mostly R-134a, guess what? It's gonna cool your car about like R-134a. BTW, the isobutane is for miscibility of the mineral oil leftover from the R-12 - helps move it through the system.

To me, Freeze-12 makes no sense from an economic standpoint, nevermind the other factors. It's basically R-134a quality cooling at double the price of R-134a. Check the website you referenced - a 30lb container of Freeze-12 is $199, they sell the same size R-134a for $96.

Industrial 12a is a mixture of propane and isobutane - basically grill gas. If you want to go this route, it's cheaper to just roll your own. There used to be an active community of hydrocarbon hackers over at aircondition.com, but they took away the alternative refrigerant board, probably for liability reasons. Lotsa folks are concerned about the fire/explosion risks of these refrigerants. I personally think the main risk is while handling them to charge the system, rather than while riding in a car using them. BTW, the EPA has ruled these types of R-12 substitutes not legal for automobiles. Apparently it's legal to sell the stuff, just not to use it.

I'm going back to work now,

- JimY