With different base materials come different tungsten electrodes with variations of material inside said tungsten. The Miller Diversion 180 comes with a 3⁄32-inch orange 2% Ceriated Tungsten and works well with steel (DC) but will break down when welding heavy (AC) aluminum with a high amperage setting. For an inverter TIG machine and welding on heavy aluminum you could try 1% Zirconium (brown), 2% Lanthanum (blue), 1.5% Lanthanum (gold) or feel free to ask your local welding supply store. Picking the right tungsten is like asking two people what time it is; you’ll most likely get two different answers. So play around with what works best for you and your machine.