A spool gun works fine. However for doing repair work on aluminum trailers, the gun was too clumsy to get into a lot of tight spaces and the gun got heavy after long use. I bought a Miller 251 with a push pull gun that I have dedicated to aluminum. However, for casual aluminum welding, a spool gun is fine. The quality of the weld is the same as a push pull. I still have the spool gun that fit on my 25 year old Millermatic 200 and never use it. It was a lot of trouble to switch back and forth. And labor with taxes and worker's comp costs me about $30 an hour, so its not cost effective to switch back and forth.
