Craig Suslosky writes:

I was curious if anyone
has tried welding alum. with one of these. I would like to weld some
1x3x11ga. alum tubing.

I have the smaller Lincoln MIG version, gas kit, and argon, and have done
several aluminum projects. It really only works at all with some practice,
and on certain thicknesses of stock. I could do an OK job on 1/8 or 1/4
inch stock. Sounds joints but not very pretty. On 0.050 sheet it would
burn through all over. Dunno what "11 ga" is, but it sounds on the thin
side. Opposite problem on thicker material, where you can't get a hot
enough puddle, and you can wind up with inadequate penetration, especially
where corners come together and increase the mass.

My best results were a vertical metal stock rack made from 2" square tubing
with 1/8 walls. In 7 perpendicular joints, they all came out strong, and a
few of the beads even looked close to a real professional type of result.

Aluminum is just a difficult material to weld, with its combination of low
melting point and high thermal conductivity. The little MIG welders don't
deal with that very well.

It isn't cheap, either, the wire and the argon gas you'll use. For me it
was more for entertainment than anything, doing something exotic yourself,
doing little projects that are too small for hiring out. making things you
just can't buy off the shelf.