[vn1500g3]

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 need to purge the inside of the tube with Argon?

Thank you for your time.

[jpence38]

That would be my first suggestion. Are the ends of the tube open or closed. Often times when you weld on tube that has closed ends, you will get a similar result from the heated air trying to escape out through the weld.