mild steel butt-weld with tig

I am a new tig welder and I'm practicing butt welds on 1/8" mild steel.The problem is I cant seem to get full penetration properly.

I have my machine set to 125amps using a foot pedal.

If I get penetration my bead is concave if I get a nice bead I dont get full penetration.I've tried 1/16" filler and 3/32" filler,more heat faster travel,less heat slower travel.

Small gap between pieces and no gap.

Im pretty sure my torch angle and dip technique are sufficient as I've been practicing running beads on aluminum like you suggest
(helped tremendously,THANKS!) and can run a nice bead at will.I just cant seem to find the right balance on this seemingly simple mild steel butt-weld!

Where am i going wrong?




I have the same problem.

1/8" seems like the limit for a full penetration single pass weld.

The only way I have been able to be consistent is with a bevel and a gap.

Dont feel bad, I see this from students all the time and have the same problem.

try knocking a bevel on it and gapping it about 3/32"


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