This machine would be only rated for 70 to 100 amps ac for GTAW aluminum. The phenomenon is called dc component. The aluminum oxide acts as a rectifier and half (positive side) of the sine wave may go back into the machine as heat. There is no thermal overload protection on that ac machine and the extra heat will melt the insulation if it is used for long welds. The price the local distributor will sell a Miller high frequency unit is over 900 bucks. There is no remote amperage control capability and a secondary on/off switch is another 300. There may be cheaper ones out there. Or spend 1500-1800/1900 for Millers Econotig or Syncrowave 180.