Tweco 300 S Arcmaster - Manual (Page 33)

ARCMASTER ® 300 S
March 31, 2006 7-1
SECTION 7:
BASIC TIG WELDING GUIDE
7.01 Electrode Polarity
Connect the TIG torch to the - / TORCH terminal and the work lead to the + / WORK terminal for direct 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.
7.02 Tungsten Electrode Current Ranges
Electrode Diameter DC Current (Amps)
0.040” (1.0mm) 30 – 60
1/16” (1.6mm) 60 – 115
3/32” (2.4mm) 100 – 165
1/8” (3.2mm) 135 – 200
5/32” (4.0mm) 190 – 280
3/16” (4.8mm) 250 – 340
Table 4 – Current ranges for varies tungsten electrode sizes
7.03 Tungsten Electrode Types
Electrode Type
(Ground Finish)
Welding Application Features Color
Code
Thoriated 2%
Ceriated 2%
Red
Grey
DC welding of mild steel,
stainless steel and copper. Excellent arc starting, Long life,
High current carrying capacity.
DC welding of mild steel,
stainless steel, copper,
l i i i d
Longer life, More stable arc,
Easier starting, Wider current
N
Table 5 – Tungsten electrode types
7.04 Guide for Selecting Filler Wire
Diameter
Filler Wire Diameter DC Current Range (Amps)
1/16” (1.6 mm) 20 - 90
3/32” (2.4 mm) 65 - 115
1/8” (3.2 mm) 100 - 165
3/16” (4.8 mm) 200-350
Table 6 – Filler wire selection guide
NOTE
The fi ller wire diameter specifi ed in Table 6 is a
guide only, other diameter wires may be used
according to the welding application.