Miller CST 282, Owner'S Manual

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OM-285986 Page 30
SECTION 9 – SELECTING AND PREPARING A TUNGSTEN
FOR DC OR AC WELDING WITH INVERTER MACHINES
9-1. Selecting Tungsten Electrode
Whenever possible and practical, use DC weld output instead of AC weld output.
NOTICE – Wear clean gloves to prevent contamination of tungsten.
A. Select Tungsten Electrode
Amperage Range By Gas Type* And Polarity
Electrode Diameter DCEN – Argon AC – Argon
(2% Ceriated, 1.5% Lanthanum, Or 2%
Thorium Alloy Tungstens)
Direct Current Electrode Negative Unbalanced Wave
(For Use With Mild Or Stainless Steel) (For Use With Aluminum)
0.010 in. (0.25 mm) Up to 15 Up to 15
0.020 in. (0.50 mm) 5–20 5–20
0.040 in. (1 mm) 15–80 15–80
1/16 in. (1.6 mm) 70–150 70–150
3/32 in. (2.4 mm) 150–200 140–235
1/8 in. (3.2 mm) 250–400 225–325
5/32 in. (4.0 mm) 400–500 300–400
3/16 in. (4.8 mm) 500–750 400–500
1/4 in. (6.4 mm) 750–1000 500–630
*Typical argon shielding gas flow rates are 10 to 25 CFH (cubic feet per hour).
Figures listed are a guide and are a composite of recommendations from American Welding Society (AWS).
B. Electrode Composition
Tungsten Type Application Notes
2% Cerium (Gray) Good all-around tungsten for both AC and DC welding.
1.5–2% Lanthanum (Yellow/Blue) Excellent low amp starts for AC and DC welding.
2% Thorium (Red) Commonly used for DC welding, not ideal for AC.
Pure Tungsten (Green) Not recommended for inverters!
For best results in most applications, use a sharpened cerium or lanthanum electrode for AC
or DC welding.
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Not all tungsten electrode manufacturers use the same colors to identify tungsten type. Contact the tungsten electrode manufacturer or
reference the product packaging to identify the tungsten you are using.