Nebraska GTAW FFA TIG Welding Practice Exam

AC balance determines how much cleaning action the arc provides compared to how much heat goes into penetrating and melting the base metal. If the balance is set too high, the arc spends too much time in the cleaning mode, which aggressively removes aluminum oxide but also starts eroding the base metal itself. That excessive cleaning can gouge or roughen the surface, leaving an uneven weld bead. In aluminum TIG welding, you want enough cleaning to remove oxide so the metal wets properly, but not so much that you remove metal or create an uneven surface. The other effects—deeper penetration, faster travel from a softer arc, or reduced shielding gas use—aren’t the primary outcomes of a high cleaning balance.