[Dick Linn]

I'm Dick's son. I think your main problem is that you need to be using AC high frequency continuous. Gas flow should be about 10-15 CFH, mainly depending on your cup size. I don't think that particular machine has a preflow so you need to hold the torch in the air, depress the pedal so it goes into postflow mode and before it turns off go to where you want to strike up. With the gas flowing press the pedal about a quarter of the way down and wait for the high frequency to start the arc (it ionizes the argon and then goes to welding amps). The electrode should be tapered and will ball up on its own when you weld. You should not have to scratch start hold the electrode about 1/8" away from your work. With aluminum clean the work with a STAINLESS brush for aluminum only, and clean your filler with a scotch brite for aluminum only. Keep your filler very low (about 10-15 degrees off work). Try connecting the ground clamp to the workpiece at least once or make sure the table actually makes good contact with the aluminum. Also, before I forget make sure it is in TIG mode! Use the tig weld calculator on the miller website to adjust your max amps and pay attention to the duty cycle!

Once again make sure it is clean. When you are done cleaning it, clean it some more. Aluminum tends to get "sucked" onto the tungsten so if that happens just break it off with pliers carefully and either point it or let it ball if its a clean break.

I've welded aluminum up to 260 amps (not fun) and spent the summer welding Inconel turbine blade tips (also not fun).
Wordy I know but these are the basics.