I work with Propylene and a Hot head torch with a propane hose. I rent a 26 lb. tank from a welding supply place in town. It runs me $4 a month and the gas runs me about $50 each time I get a new tank. Just make sure the fittings are TIGHT!!! The 1st time I used it we thought it was on tight and everything was going good until the thing flared up on me!! Scared me half to death!! My torch was on fire from where it was attached all the way up the torch!
I now make sure everything is tight, tight, tight whenever I have to change tanks!