Hey guys, I've had a 250 PI for about 5 years now, and I've been happy with it, it's held up pretty well with no major issues. I don't do much Aluminum welding, but when I do I have a sputtering arc issue. The arc sputters whenever I ease off the pedal, especially at the end of a weld or when trying to pulse the pedal. It still welds ok, but it seems to get worse the longer I work. It does affect the appearance of my welds when it's hard to hold a steady arc. Sometimes it's very difficult to get the arc started, and it will just sputter like crazy. Scratch starting will usually start it right up. For this instance, I was lap welding 1/4" 6061 using 3/32" 2% Thoriated Tungsten and 3/32 rods, 4043 I believe. AC Freq is maxed, AC Balance is about halfway, line pointing straight up. Adjusting balance does not seem to help the issue. Below is a video where you can hear the problem. Also, here are 3 pictures of my welds. I was just screwing around, but the first picture is my first weld, and they got progressively worse from there. Any ideas or suggestions?
Second, sputtering gets worse: