For GTAW, what type of electrode is best for aluminum?
For most materials, including steel, a two percent thoriated tungsten electrode is recommended, but since aluminum is welded with AC rather than DC, the electrical characteristics are different and the amount of energy put into the tungsten electrode is higher when AC welding. For these reasons, pure tungsten or zirconiated tungsten are recommended for aluminum welding. In addition, the electrode diameter for AC welding has to be significantly larger than when using DC. It is recommended to start with an electrode that is 1/8″ and adjust as needed. Zirconiated tungsten can carry more current than pure tungsten electrodes. Another helpful hint for AC welding is to use a blunt tip – the arc tends to wander around a pointed tip.
