And if you can get a can tap that'll fit the cans, you can take the totally oil-free refrigerant from those cans and put it into your car's AC system, and add only the specified amount of oil (which is usually about two ounces) rather than use the "recharge" cans that have a lot of oil in them.
...and the computer dusters are slightly cheaper.
For his "off-label" use of this stuff, the guy is probably breaking about a thousand federal laws that no one but the EPA knows about.
1) It turns out that hydrofluorocarbons like R134a are just as "bad" for the ozone as chlorofluorocarbons are--according to the greenies, anyway--and
2) This way the HFC ends up contained in an air conditioner rather than dumped into the atmosphere where it can doom us all to a future dystopia of skin cancer.
Of course, all of this is total horseshit anyway.
...what I should do is make a post about the ozone hole and just link to it whenever I get onto the topic, because it really does get tedious for me to type out the whole thing every time. Maybe if I moved the Fungus to a proper blog forum, I could even have links in the sidebar and just say, "Ozone hole: look in the sidebar!" and not waste everyone's time.
But the ban on CFCs really was a solution in search of a problem, and the biggest beneficiary of the ban turns out to be DuPont, which owned the patent on CFCs which was expiring about the time the ozone hole was suddenly discovered by the econuts, and which also had brand new patents on HFCs which it couldn't make any money on so long as CFCs were still available. This is why DuPont gave a lot of money to groups agitating for a CFC ban.
I wonder if those greenies ever figured out that they were duped?
* * *
Anyway, it's fortunate that there are a lot of chemicals with the right properties for use as refrigerants. You can use anything which is approximately liquid at room temperature but which has a fairly low transition temperature, and it's better if it has to be under some pressure to remain a liquid over, say, 40° or so.
Almost all of the energy consumed by an air conditioner is used compressing the working fluid. You compress it and then run it through a radiator to cool it (this radiator is called the "condenser" for that reason) and then you let it bleed out through an orofice into another radiator called the "evaporator". Semi-adiabatic cooling, blah blah blah--look up the gas law and do the math--the lower the boiling point at ambient pressure, the better your air conditioner works. You can use propane (R290) if you like--it works very well as a refrigerant!--but if you get a leak there can be a fire or explosion. Ammonia (R717) works, but a leak can kill you.
Something highly inert and stable like a chlorofluorocarbon is perfect. Freon was used as a propellant in aerosols because it's highly nonreactive; you could mix it with all kinds of common chemicals and it wouldn't react at all.
It boils at -21.6°F, it's got a nice high specific heat capacity, and it was cheap to manufacture, too.
Look at all these refrigerants!
* * *
In an hour or so I really do have to go outside and cut the grass. *sigh*