Problem resolved! I tried the flame test with the cup on: not a flicker. I removed the cup, collet, etc. and tried again: instantly out! I inspected the collet, electrode, etc and didn't find anything obvious, but cleaned them up with acetone anyway. Reassembled and ran the flame test again: instant...

Thanks for the suggestions; I'll try going down that path tomorrow and see what I find. I'm glad to hear that it's (probably) not my imagination. I really like the flame suggestion! Of course you're right about the CO2/Argon thing; after all the messing around, I ran out of Argon and decided to try ...

Hi all, I'm a hobbyist with no formal training, but I have welded occasionally over the past couple decades... the most complicated project being a set of mild-steel headers for a corvette. I have a Lincoln Precision TIG 185 I bought about six years ago, but haven't used for two or three. I just tri...