Originally Posted by
MassiveD
You can build a bike with just an air mapp torch. Or even an air propane one, which is cleaner in my experience.
While it is possible to build a frame with a fuel/air setup, it paradoxically can result in much larger heat-affected areas on the tubes. With a good fuel/oxygen setup you can heat the work to the necessary temperature quickly, braze the joint, and get out much faster, so less of the tube is weakened by the heat.