Maybe some one can tell me what I'm doing wrong. Every time I try to TIG weld on 0.065 wall SQ Steel tubing, the weld seems to bubble up. I'm welding at around 90A, 15CFH Argon with 1/16 2% Thoriated rod. I've cleaned the tubing to remove all the mill scale, but still the weld bubbles up. WTF? Do I ...