The spool gun is used for when welding aluminum, becasue you have to use aluminum wire. The problem is, with aluminum wire, it is extremely soft, and bends and and what not, damaging the wire, and damged wire=no good for welding. The spool gun elimantes this. I have a Precision 185 from lincoln, and love it, but I can't TIG at all. SO if you find a place that can teach, let me know.