i do heating and cooling for a living and braze with mapp gas everyday. it takes a lil while to heat 7/8 copper with map gas so i would believe it would take a long time to heat a 2inch pipe to the right temp. i would use oxygen also. not too sure on what type of brazing rod to use on that type of metal but if u go to any heating and cooling supply house they could set u up with everything u need to do the job
