TIG Welding Aluminum Fundamentals

Aluminum presents unique challenges that make it one of the most demanding metals to TIG weld. Its melting point is 1,221°F—far below steel's 2,500°F—yet its oxide layer melts at 3,700°F, meaning the oxide skin must be broken before the base metal can fuse. Aluminum conducts heat five times faster than steel, so the weld puddle forms quickly and can burn through without warning. These properties require alternating current (AC) output, which uses the electrode-positive half-cycle to blast away the oxide and the electrode-negative half-cycle to provide penetration.