Choosing a tungsten electrode: which colour for which job?
The colour at the end of a tungsten electrode tells you which alloy it is. That alloy decides how easily the arc starts, how stable it stays and what kind of welding the electrode suits. This is an overview of the common types.
The colours and what they mean
- Green: pure tungsten. Mainly used for aluminium with alternating current (AC). An older choice, not the best for DC.
- Red: tungsten with thorium (2%). Good for DC and a stable arc. Thorium is slightly radioactive, which is why it is used less and less. Take care when grinding.
- Grey: tungsten with cerium oxide. Starts easily at low current and suits AC and DC.
- Gold: tungsten with lanthanum (1.5%). Suits AC and DC, with a stable arc.
- Blue: tungsten with lanthanum (2%). Versatile for AC and DC and a popular choice.
- Purple (E3): a mix of rare earth oxides. An all-rounder for AC and DC that suits steel, stainless and aluminium.
Which one to choose?
If you want one electrode for everything: a lanthanum or E3 electrode. If you only weld aluminium, lanthanum or pure tungsten is often used. For low current and thin plate, cerium oxide is a good choice.
Grinding
- Grind lengthwise along the electrode, not across it. That keeps the arc running straight to the workpiece.
- A point about two to three times the diameter in length is a common guideline for DC.
- Use a grinding wheel only for tungsten, so no contamination gets into the electrode.
Diameter
The diameter depends on your amperage. A thinner electrode suits low current, a thicker one suits high current. Choose the diameter according to the recommendation of your welding machine or torch supplier.
Our electrodes
Take a look at our electrodes, including the purple E3. Do you have a question about which electrode suits your work? Send us a message through the contact page.