I have an aluminum welding question for the experts out there. I have been welding Steel for a number of years now and I decided to build something out of aluminum. I am using 1/8th 6061 aluminum 2 inch square tubing for this project. I am also using an Miller 250 MIG welder with 100% argon and .35
4043 wire. Anyhow, it seems that no matter what heat or wire speed, my weld ends up "falling-in" a little at the end. It does not fall all the way through, but it looks no where near the rest of the weld. It looks like it could crack and it is not very nice to look at. I have tried double backing and even re-striking the arc, but it just moves the "falling-in" spot to wherever I stop welding. Just for a reference I have tried using between 19-22 volts and wire speed between 300-500. Just about every setting seems to give me the same results. If someone knows what I am doing wrong, please tell me before I pull all my hair out! Thank you!-Bob