Which practice is NOT recommended for preventing tungsten erosion?

• A. Having good mechanical and electrical contact
• B. Using as low a current as possible
• C. Using a water-cooled torch
• D. Using as long an electrode extension from the collet as possible

Answer: (D)

Tungsten erosion happens when the arc concentrates heat at the electrode tip, wearing it away. To keep erosion down, you want a stable, heat-controlled arc and a setup that actively removes excess heat from the tungsten.

Good mechanical and electrical contact helps the arc stay stable and centered, reducing arc wander and hot spots at the electrode. Using the lowest current that still maintains a stable arc minimizes heat input to the tungsten. A water-cooled torch cools the torch head and tungsten area, further lowering the temperature and slowing erosion.

Extending the electrode length from the collet increases the arc length and places more heat directly at the tungsten tip, which speeds up erosion and can lead to instability and contamination. So keeping the electrode extension short is part of preventing tungsten erosion, while the other practices support that goal.