I have been welding and fabricating for over 45 years, and professionally for more than 30. I have been certified under numerous AWS and ASME procedures in the nuclear industry. However I am new to inverters, having just purchased an Everlast Powertig 255 EXT. I am having trouble with arch stability at low settings on aluminum, specifically beverage cans. I can run a nice bead and have no problem welding two together with my old Miller 250 HF set on 25 amps. That’s using a WP 26 torch that is stiff as a board, a 3/32 tungsten and either a 3/32 or 1/16 filler.

Most of the time the arc pops repeatedly like it keeps going into the HF start mode and will not focus at the end of the tungsten. I've read the manual several times, spoke to Ray in technical, tried numerous cups, tungsten sizes, argon flows, and machine settings. I don't have this issue on heavier aluminum or in DC mode even on very low settings. The 255 EXT has many features and settings that should make I much easier to control while welding thin aluminum. I don't know if I am unable to set the machine properly or if something is wrong with it. I tried setting it at 25 amps, sine wave and 60 Hz which is the only setting for my old miller HF machine and got no improvement in arc performance.

Help or suggestions will be greatly appreciated.