Welders...

[JET]

Mig can weld alumium piping as long as you set everything right, and you have a spool gun or a push-pull setup.

A MIG setup to do aluminum will cost well over a grand, and doing thin aluminum with them is tricky. Spool guns are really meant for production work and long beads. They also tend to put a ton of heat into the material and warp flanges.

[A//// Guy]

Just make sure they can do the thickness you want without having to wait 10 minutes in between welds. The cheaper smaller machines you have to wait a while in between 30 seconds of constant welding because of overheating...

The hobart 140 like Jet said is probably the bottom level machine to start with. It does up to 1/4 inch metal and has the gas kit included- minus the tank...

[JET]

Yes, flux core wire sucks. You want a welder that uses gas from a tank.