Phil, most of the silver solders are 1100+ F so you should be ok. not sure about the burning temp of butane iirc its close to propane....i use propane and it works perfectly. Oxy Acetylene is a lot more difficult because its is too hot - wrecks the flux of you are not careful about applying it indirectly. Use only if what you are soldering is so massive it sinks a lot of heat. do you have SS experience? happy to give you some basics if not. as for sourcing SS, I've always gone to welding supply places or industrial supply for it, have you checked the usual large supply suspects, msc etc?