Maybe if you silver braze. Not likely with brass. Unless, you are running an oxy/mapp setup. Then yes, but realize you'll have to clean the surfaces to be joined. Not sure if the reducers are chromed (I'm guess yes, or galvanized at the very least) Regardless, both coatings will need to be ground/sanded off in order to the braze to hit. Also, heating galv. to the temps necessary to braze will flash off the zinc, which is not too awesome for your body. Respirator if you do this (I'm guessing welding on chrome is just as nasty.) Best bet might be to find some mild steel that hasn't been plated yet (available at hardware/menards/lowes/home depot type stores - labaled as weldable steel) and cut it to fit.
