Which tungsten electrode classification is associated with a red stripe?

• A. EWTh-3
• B. EWTh-2
• C. EWTh-1
• D. EWTh-4

Answer: (B)

Red stripe on a tungsten electrode identifies a thoriated tungsten with about 2% thorium oxide, the EWTh-2 class. The thorium oxide improves electron emission, which helps with easy arc starting and a stable arc at higher currents. That makes it a practical choice for DC welding of steel and stainless steel, and it tends to have longer electrode life than pure tungsten. Different color codes exist for other thorium contents or for different dopants, but the red stripe specifically signals the 2% thorium variant. Remember to handle thorium-containing electrodes with care due to radioactivity and follow proper safety practices during grinding and disposal.