Well I guess I answered my own question. I finally got all the bits that I needed to use the Hobart 140 on Aluminum - I bought a teflon gun liner, and then at the suggestion of tech support, a knurreled roller. I also put in 0.035 5356 wire into the unit. No problems pushing it thusfar (knock on wood) butI have been keeping the gun pretty straight. Also, the only fuse in my garage is 15A, even with the volts and amps turned up for Al, I didn't trip the breaker, so I feel pretty good about not hurting the equipment though I am running at a slightly higher wire size (0.035 instead of the recomended 0.030).