What is the proper tungsten tip preparation for AC TIG welding?

• A. Grind the tip to a sharp point
• B. Leave the tip as received
• C. Lightly ball the tip
• D. Bend the tip toward the work

Answer: (C)

In AC TIG welding, you want the tungsten tip lightly balled. The rounded end provides a stable, easily reignited arc as the current reverses, which helps keep the arc consistent during the alternating polarity used for cleaning and penetration. A pointed tip tends to erode faster and can cause an unstable, wandering arc in AC, making control more difficult and increasing contamination risk. Leaving the tip as received or bending it toward the work doesn’t set you up for the right arc characteristics—besides, bending toward the work can lead to contact with the weld or contamination. Balling the tip just enough gives you a reliable, controllable arc for AC TIG.