15
14
For Weldarc 145 & 185 only, use the Weld
Mode Selection Switch to select Stick Mode.
Select an appropriate welding current for
the electrode diameter by setting the knob
on the machine front panel. WIA Austarc
electrodes will give the best results.
To Strike the Arc:
With VRD enabled, touch-twist-lift.
With VRD disabled, drag the end of the
electrode along the work piece as if striking
a match.
As the arc initiates, lift the electrode slightly
away, aiming to establish an arc length of
approximately 3mm.
As the electrode end is consumed, feed
the electrode into the arc in order to
maintain arc length. As a general rule, the
arc should be held as short as possible
while still giving stable burn off and good
weld appearance. An arc which is too long
may cause an unwieldy flow of metal with
a rough weld appearance and reduced
penetration. An arc too short leads to a
narrow weld deposit and “stuttery” arc
characteristics, and the electrode is liable
to freeze onto the work piece.
As the solidified weld deposit forms,
move the end of the electrode slowly
along the weld path, aiming to maintain a
pool of molten weld metal behind the arc.
Decreasing this rate of travel will result in a
wider weld deposit, and similarly increasing
it will narrow the weld deposit.
Always fill the crater which tends to form
at the end of a weld deposit, by pausing
momentarily before withdrawing the
electrode to break the arc. Unfilled craters
are a point of weakness, and can lead to
weld cracking.
TIG Welding (GTAW)
Connection for TIG Welding
(145 & 185 only)
For TIG Welding, the torch is connected
negative terminal. Figure 4 illustrates the
correct connection of the welding torch.
The machine does not have an internal
gas valve, therefore, the gas supply needs
to be controlled externally with a torch that
incorporates a manual valve in the hand
piece. Welding grade Argon is the
shielding gas most commonly used for
DC GTAW welding.
Before first use of the welding torch, allow
gas to purge the torch and hoses for
30 seconds 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. 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 6mm from the
ceramic gas nozzle.
Current Range for General Purpose
Electrodes
Diameter (mm)
Current (Amps)
2.0
40 - 60
2.5
60 - 85
3.2
90 - 130
4.0
130 - 180
