Miller Maxstar 140, Owner'S Manual

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OM-2224 Page 32
SECTION 8 – GUIDELINES FOR TIG WELDING (GTAW)
8-1. Positioning The Torch
Ref. ST-161 892
Y
Grinding the tungsten elec-
trode produces dust and fly-
ing sparks which can cause
injury and start fires. Use lo-
cal exhaust (forced ventila-
tion) at the grinder or wear
an approved respirator.
Read MSDS for safety infor-
mation. Consider using
tungsten containing ceria,
lanthana, or yttria instead of
thoria. Grinding dust from
thoriated electrodes con-
tains low-level radioactive
material. Properly dispose
of grinder dust in an envi-
ronmentally safe way. Wear
proper face, hand, and body
protection. Keep flam-
mables away.
1 Workpiece
Make sure workpiece is clean
before welding.
2 Work Clamp
Place as close to the weld as
possible.
3 Torch
4 Filler Rod (If Applicable)
5 Gas Cup
6 Tungsten Electrode
Select and prepare tungsten
according to Sections 7-1, and 7-2
or 7-3.
Guidelines:
The inside diameter of the gas cup
should be at least three times the
tungsten diameter to provide ade-
quate shielding gas coverage. (For
example, if tungsten is 1/16 in
diameter, gas cup should be a
minimum of 3/16 in diameter.
Tungsten extension is the distance
the tungsten extends out gas cup
of torch.
The tungsten extension should be
no greater than the inside diameter
of the gas cup.
Arc length is the distance from the
tungsten to the workpiece.
1
10–25
°
10–15
°
6
2
3
4
90
°
4
5
3/16 in
1/16 in
6
5
Bottom View Of Gas Cup