16
Operators Manual
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TIG Welding (GTAW)
Connection for TIG Welding
For TIG welding, the torch is connected to
the negative terminal. Welding grade Argon
is the shielding gas most commonly used for
DC GTAW welding. The gas is connected
directly to the torch.
Before first use of the welding torch,
allow gas to purge the torch and hoses for
1 minutes at approximately 10 litres/min. For
welding purposes, the gas flow rate should
be set in the range 2-5 litres/min.
Tungsten electrodes for DC GTAW should
be 1-2% Thoriated or Witstar. This type will
provide the best arc initiation, arc stability and
tip shape retention characteristics. Thoriated
electrodes can be recognised by a red coded
end. The tungsten electrode is ground to
a point, with the grinding marks pointing
towards the tip. For welding currents less
than 20 amps, the included angle of the
point should be 30
o
, for currents greater than
20 amps, the recommended angle is 60
o
.
When set in the torch, the tungsten should
protrude 6 mm from the ceramic gas nozzle.
TIG Welding Operation
Connect the Work Clamp to the work piece.
Turn on the power switch located on the rear
panel. Wait approximately 5 seconds as the
unit goes through its initiation sequence.
Press the Weld Mode button until the TIG
Mode light is on. The Weldmatic keeps the
last mode used in memory, so this step is
only necessary when using a different mode
to that used last.
Select an appropriate welding current for the
job by setting the knob on the machine front
panel.
Use of a copper striking plate can be used to
avoid electrode contamination. The electrode
can also be contaminated by contact with
the filler rod. A contaminated electrode
produces an unstable arc. If this occurs
regrind the electrode tip.
TIG Local / Remote Mode
When in Local Mode the output is turned on
and the LIFT-ARC voltage is present at the
electrode.
When in Remote Mode the output can be
turned on by Torch Trigger switch connected
to the remote plug.
