37
GUIDE TO TIG WELDING
Before starting any welding activity ensure that you have suitable eye protection and
protective clothing. Also take the necessary steps to protect any persons within the welding
area.
TIG welding consumables
The consumables of the TIG welding process are filler wires and shield gas.
Filler wires
Filler wires come in many different material types
and usually as cut lengths, unless some automated
feeding is required where it will be in reel form.
Filler wire is generally fed in by hand.
Always consult the manufacturer
’
s data and
welding requirements.
Gases
Shielding gas is required when welding to keep the weld pool free of oxygen. Whether you are welding
mild steel or stainless steel the most commonly used shielding gas used in TIG welding is argon, for more
specialised applications an argon helium mix or pure helium maybe used.
TIG welding arc starting
-
Lift TIG (lift arc)
Not to be confused with scratch start, this arc starting method allows the tungsten to be in direct contact
with the work piece first but with minimal current so as not to leave a tungsten deposit when the
tungsten is lifted and an arc is established.
With lift TIG start the open circuit voltage (OCV) of the welder folds back to a very low voltage output
when the unit senses it has made continuity with the work piece. Once the torch is lifted the unit
increases output as the tungsten leaves the surface. This creates little contamination and preserves the
point on the tungsten although this is still not a 100% clean process.
The tungsten can still get
contaminated but lift TIG is still a much better option than scratch starting for mild and stainless steel
although these methods of arc starting are not a good option when welding aluminium.
Filler Wire Diameter
DC Current Range (Amps)
1.0mm
20
-
90
2.4mm
65
-
115
3.2mm
100
-
165
4.8mm
200
-
350
Filler Wire Selection Guide
