Welding Aluminum with a MIG Welder is not difficult at all. You need to use straight Argon as a shielding gas and a Nylon Liner to keep the wire from hanging up. Of course the best way to go is to use a Spool Gun so that wire jams are not a problem. I bought my Miller 200 and Spool Gun over ten years ago to build several hundred feet of Aluminum ornamental deck railing for a multi-million dollar oceanfront home I was remodeling. While I was at it I used left over materials to build an Aluminum rack for my rig. It is light enough that I can put it on by myself, even with the Hi-Lift bolted to it, and I have had six big guys stand on it for hours while watching a desert race. As someone noted, you do have to weld a little faster than you would on steel.
