I learned to soft solder from my grandfather (born in 1894). He liked using soldering coppers (looks like short fireplace pokers with a fat head). We would heat them on the kitchen stove and you could solder 36" of thin metal until it was too cool to keep working. In the garage, he had a brass plumbers "furnace" basically a white gas pump up burner to heat them. He also had an electric iron about the size of a road flare. That would work quite well but once he was doing a rain gutter and the 100' 12 gauge electric cord ran out of amps to get it hot enough. My teen years as a "Pool Boy" we used Acetylene hand torches (American torch) for up to 3" copper pipes. That made a big difference. Propane would not work past 1.5" copper. We never used MAPP so I have no experience. I never soldered anything but sheet steel. Galvanized was tough, but a real acidic flux was the key. The most fun was the hard coal forge about the size of a small suitcase. Get that going and he would make chisels, hardened washers and yard tools. Ah, to be a kid again...

Dave