That 1957 Miller looks a lot like a 1983 Miller Gold star 330 that I have in my shop. It has a max output of 435 amps. If my memory serves me it cost me around $3000 new. I paid for it the first month I had it. Never had a problem with it. Still works like new. Best tool I ever bought. I can't do the beautiful welds I did 15 years ago but its not the welders' fault. Ha You can weld .010" aluminum with it if you are current...by that I mean that you weld several hours a week. I weld maybe 2 hours a year now and I wouldn't try anything less than say .040".

If you a going to do some serious aluminum and thin you need to think remote foot pedal amperage control, water cooled torch because they are about 1/3 or 1/4 the size of an air cooled one. The cable is also water cooled and is so flexible making intricate work a breeze.