Basic Welding Guide; Electrode Polarity; Tungsten Electrode Current Ranges; Tungsten Electrode Types - Thermal Arc ARCMASTER 300 MST Operating Manual

5.0 BASIC WELDING GUIDE

5.01 Electrode Polarity

Connect the TIG torch to the - /
current straight polarity. Direct current straight polarity is the most widely used polarity for DC TIG welding.
It allows limited wear of the electrode since 70% of the heat is concentrated at the work piece.

5.02 Tungsten Electrode Current Ranges

Electrode Diameter
0.040" (1.0mm)
1/16" (1.6mm)
3/32" (2.4mm)
1/8" (3.2mm)
5/32" (4.0mm)
3/16" (4.8mm)
Table 7 – Current Ranges for Various Tungsten Electrode Sizes

5.03 Tungsten Electrode Types

Electrode Type
(Ground Finish)
Thoriated 2%
Zirconated 1%
Ceriated 2%
TORCH
terminal and the work lead to the
Welding Application
DC welding of mild steel,
stainless steel and copper.
High quality AC welding of
aluminium, magnesium and
their alloys.
AC & DC welding of mild steel,
stainless steel, copper,
aluminium, magnesium and
their alloys.
Table 8 – Tungsten Electrode Types
AC Current (Amps)
30 – 70
60 – 95
125 – 150
130 – 225
190 – 280
250 – 340
Features
Excellent arc starting, Long life,
High current carrying capacity.
Self cleaning, Long life,
Maintains balled end, High
current carrying capacity.
Longer life, More stable arc,
Easier starting, Wider current
range, Narrower more
concentrated arc.
30
+ / WORK
terminal for direct
DC Current (Amps)
30 – 60
60 – 115
100 – 165
135 – 200
190 – 280
250 – 340
Color
Code
Red
White
Grey