Is it possible to weld aluminum with the Forney 140 MIG?

Assuming you have the right gas, you can weld aluminum with the 140 MIG, but it’s not capable of using a spool gun.  We suggest you change the liner in the lead to a Teflon or plastic one instead of the steel liner that comes in the lead.  Aluminum wire is a lot softer and can get caught in the steel liner.