It can be but you need a vaccum pump and the disconect fittings for the automotive type fittings and all that other garbage. Refrigerant is about $35.00/lb so you won't be saving much in the long run.
Untill you start filling other peoples cars.
01 gtp-big cam e85 dd 78dodge- guzzling fuel 05 cummins- rollin coal
SMGPFC Two Nipple General