For AC welding, which end is used?

• A. Pointed end
• B. Flat end
• C. Balled end
• D. Rounded end

Answer: (C)

Use the balled end on the tungsten electrode. In AC TIG welding, the alternating current cleanly removes oxide on metals like aluminum, and a ball-shaped tip provides a stable, ignitable arc and reduces the tendency for the electrode to stick or contaminate the weld. A pointed tip tends to erode unevenly and can cause arc instability or tungsten inclusions, which is less desirable with AC. The rounded tip is preferred because it handles the polarity switching smoothly and helps produce a consistent weld bead.