Real-world starting settings for MIG, TIG, Stick and plasma cutting
Yes, but you'll need a spool gun or push-pull setup (or a liner rated for aluminium wire), ER4043 or ER5356 wire, and 100% argon shielding gas. Standard steel liners will bird's-nest soft aluminium wire.
Usually contamination (oil, oxide layer, or moisture) or insufficient shielding gas coverage. Clean with a dedicated stainless brush and acetone before welding, and check your gas flow and torch angle.
That's heat tint from oxidation — more shielding gas coverage or a slower travel speed can reduce it. For fully clean welds, back-purge with argon on the reverse side.
Not practically. Aluminium stick electrodes exist but are difficult to run well and rarely used outside emergency repairs. TIG or MIG (spool gun) is strongly recommended instead.