Thanks for all of this information, Doug. Very useful.

Because of this thread, I bought a propane elbow and some tips for my Smith A1WA. I chuckle to myself thinking of the run on used oxygen concentrators by frame builders, but it sure makes sense from a safety and convenience point. Just to be safe, I decided to buy the proper rated hose for all fuels, so I got a length of the regular rubber type and a kevlar section. If feels rather flimsy, but the kevlar hose is awesome at the torch end and I highly recommend it. Unfortunately (but not unexpectedly), my attempt to practice a joint with propane felt like trying to write left-handed. The fillet was okay and seems plenty solid, but didn't look as nice as I can normally pull off w/ acetylene.

I need to re-read this thread to fine-tune the flame I'm using (and practice), but I didn't really have much trouble with lighting the flame or keeping it lit. If nothing else, price and convenience of LP makes me want to pursue this as an alternative to acetylene. The addition of the concentrator being useful for either fuel does seem like a smart alternative to a high-pressure bottle, so maybe in the near future.