I thought I posted this earlier, but I guess not. I made a few attempts at welding brass and realized I didn't know which polarity to use. Both worked, but I had less porosity with AC than DC. Also noticed white smoke and the piece had a white film like what happens when you weld on galvanized steel. Should I be worried about the fumes? would I need a respirator or can I just set up an exhaust system? Haven't tried brazing or silver soldering the brass yet, will I get the same fumes and discoloration of the surrounding metal?