Tweco 400 MSTP Arcmaster - Manual (Page 62)

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9.03 TIG Welding Problems
Weld quality is dependent on the selection of the correct consumables, maintenance of equipment and proper
welding technique.
Description Possible Cause Remedy
1 Excessive beard build-up
or poor penetration or
poor fusion at edges
of weld.
Welding current is too low. Increase weld current and/or faulty
joint preparation.
2 Weld bead too wide and
flat or undercut at edges
of weld or excessive
burn through.
Welding current is too high. Decrease weld current.
3 Weld bead too small or
insufficient penetration
or ripples in bead are
widely spaced apart.
Travel speed too fast. Reduce travel speed.
4 Weld bead too wide or
excessive bead build up
or excessive penetration
in butt joint.
Travel speed too slow. Increase travel speed.
5 Uneven leg length in
fillet joint.
Wrong placement of filler rod. Re-position filler rod.
6 Electrode melts when arc
is struck.
Electrode is connected to the
‘+’ terminal.
Connect the electrode to the
‘
−’ terminal.
7 Dirty weld pool. A Electrode contaminated through
contact with work piece or filler
rod material.
A Clean the electrode by grinding off
the contaminates.
B Gas contaminated with air. B Check gas lines for cuts and loose
fitting or change gas cylinder.
8 Electrode melts or
oxidizes when an arc
is struck.
A No gas flowing to
welding region.
A Check the gas lines for kinks
or breaks and gas cylinder contents.
B Torch is clogged with dust. B Clean torch.
C Gas hose is cut. C Replace gas hose.
D Gas passage contains impurities. D Disconnect gas hose from
torch then raise gas pressure and
blow out impurities.
E Gas regulator turned OFF. E Turn ON.
F Torch valve is turned OFF. F Turn ON.
G The electrode is too small for the
welding current. G Increase electrode diameter or
reduce the welding current.