[Speedslug]

The rubber membrane in an acetylene regulator will do a chemical reaction over time with propane I think.

I have read somewhere that acetylene welding hoses will gum up and spit crap into the tiny passages in glass torches so the same should be true of the regulators.

Bar-b-que grills have regulators that reduce the 3 thousand psi pressure in a propane tank down to something close to 4 psi which is low enough that you don't need to have a gage telling you how much psi going into the type "T" hose that connects to the torch.