BTW: The reason I was running at 35 PSI is because that was the recommended level in the instruction manual that came with the unit. The pressure was specified in a range (Pascal units) in which the mid-point converted to 35 PSI.

Anyhow, I made a welding cart of aluminum this weekend and also did 4 hours of 7018 stick work on 1/2" steel plate. The Power Pro 205 is doing fine but I probably should have got the next bigger model. Much of the AL TIGging this weekend was at 160-180 Amps which is the edge of the machine. I was staying with about a 50% duty cycle and the machine didn't hiccup. I like it. It's a keeper.