A few years back I bought and Miller mig because it had a spool gun for doing aluminum welding. I have only used it a few time and found some pre-heating of the aluminum is needed to get a weld. I have since bought a Tig welder to do the aluminum welding. It worked much better (I am not a pro-welder) Mig aluminum you need to push weld and the bead is much higher then a tig weld and you still need to get an Argon bottle for either type.