TIG Welding Aluminum
Tungsten Inert Gas (TIG) welding—more formally known as Gas Tungsten Arc Welding (GTAW)—is well-suited for welding aluminum. Although the process is significantly slower than GMAW (MIG), TIG welding offers unmatched control of weld penetration and profile. This level of control is enhanced by the features available on modern TIG welders.
Preparing to Weld
Even with modern equipment, welding aluminum is very much like painting: preparation is key. The cause of a lot of headaches when TIG welding aluminum is related to aluminum oxide. This protective oxide layer has benefits for parts in service but must be removed from around the weld joint by using a stainless-steel wire brush—one dedicated to aluminum only—prior to welding. If not removed, the oxide layer may limit weld fusion and overall control in the welding process.
The aluminum oxide layer is also well-suited to trapping and retaining moisture that becomes a source of weld metal porosity. For this reason, preventing condensation formation on both the base metal and filler metal is also critical to achieving good quality. At the very least, allow filler metal and base metal to thermally acclimate to the welding environment before use. Consult with filler metal manufacturers to learn more tips about how to combat porosity when welding aluminum.
“The aluminum oxide layer is also well-suited to trapping and retaining moisture that becomes a source of weld metal porosity.”
Pure tungsten electrodes were once the industry standard for TIG welding aluminum since these electrodes formed a nice “balled” tip that performed well when using alternating current on older transformer-based equipment. However, ceriated tungsten electrodes have become the norm with newer inverter-based power sources. Preparing ceriated tungsten for welding aluminum involves simply grinding the end of tungsten to a point at a 60-degree angle, give or take depending on the desired arc cone.
