inverter welding on aluminum

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Aluminum welding questions for the board.I want to weld aluminum in TIG (and MIG) mode using an inverter welder like a POWCON, ARCON, or similar units. I will mostly be doing work on small to moderate sized castings and sheetmetal, pulleys, tubing, etc. Also would like to know if one can weld copper and bronze with this setup. Can this be done or does it have to be done with an AC unit. if it can be done, what are the techniques, attachments, materials, etc. that I will need to have and learn. I have read a number of boards where it was said that AC is the best choice for Aluminum but I dont have room for as many welders or budget for specialty ones, that I would like. What can I do with what I have, and how?Powcon SM, 150A tig torch, looking for a wire feeder.thanks in advance for the info.
Reply:For Tig on aluminum, you need AC. And lots of amps. But for Mig on aluminum, an inverter will work fine- I use my  miller 304 to run either spool guns or an xr push pull gun, and the inverter actually gives a better mig weld than any other power supply I have. Which is not to say that any mig weld on aluminum is really that great. Maybe the new pulsed 350 millermatic is better, but I am never very happy mig welding aluminum. Messy, smoky, spattery, and hard to get good looking welds, especially short ones. Anything over a couple of inches, and you can get in the groove and make a nice bead, but starts and stops are hard.For copper and bronze, DC Tig works fine- its nice to have a high frequency start, but not essential. But copper alloys will suck up even more amps than aluminum- the stuff gets really hot, too. We found our syncrowave 350 was at the limit of its power on a copper job a while ago, running long beads in 1/4" plate and 1 1/2" schedule 40 pipe. 400 or 500 amps would have been better. The guys who work for me worked on the miller dynasty ac/dc tig inverters at school, and except for how loud they are when tig welding aluminum, they really like them. I love my 304- no AC, but for mig, tig or stick, it cant be beat. The most multipurpose machine I own, and also gives the best weld in each mode of any machine I own. I have added a high freq box and a radiator to it for tig, and plug in any of several wire feeders for mig.