Wow, Bruce, this is really nice--it's the first time I've seen this thread. It's a great boiler and you've done a beautiful restoration. I was particularly impressed with the burner which would also work well for a hot air engine--very well engineered. Did you have to change out the jet to a smaller size for propane? Any way to refit those nice early try cocks with the round handles? I still have a hard time believing this was home built in a shop--looks factory to me.
Brent