Firepower MST 140i, Operating Manual

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Firepower MST 140i
BASIC WELDING GUIDE 4-22 Manual 0-5338
4.07 TIG (GTAW) Welding Problems
FAULT CAUSE REMEDY
1 Excessive bead 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 or oxidizes
when an arc is struck.
A TIG Torch lead
connected to positive
welding terminal.
A Connect TIG Torch lead to negative welding
terminal.
B No gas flowing to weld-
ing region.
B Turn TIG Torch gas valve ON. Check the gas
lines for kinks or breaks and gas cylinder
contents.
C TIG Torch is clogged
with dust or dirt.
C Clean TIG Torch.
D Gas hose is cut. D Replace gas hose.
E Gas passage contains
impurities.
E Disconnect gas hose from the rear of Power
Source then raise gas pressure and blow out
impurities.
F Gas regulator turned off
or cylinder shut off.
F Turn on.
G TIG Torch valve is
turned off.
G Turn on.
H The electrode is too
small for the welding
current.
H Increase electrode diameter or reduce the
welding current.
I Power Source is set for
MIG welding.
I Set Power Source to LIFT TIG mode.