I have an Italian made Astro 130 MIG welder that normally has .023 wire mounted in it. Last night I tried to weld some 1/8" tube and switched to .030 wire and the darn thing just wouldn't feed the wire right. The wire drive seemed to slip no matter how tight I made the tension spring. I fiddled for an hour and never got the magic crackle sound of a nice weld.
Switched back to .023 and it worked fine, but the depth isn't what I wanted for the thicker material.
Why would the welder not want to handle heavier wire?