arcing off side of tig cup

by Mike De Jong
(Chicago Heights, IL)

Awesome website, I wish I could go to your school. I was tacking some some 1/4 inch flat metal to the end of a 1/8 wall square tube (both 304L stainless)and every once in a while when I hit the pedal the arc would jump off the side of the cup, and one time it actually melted a little chunk off of the cup. What could be the cause of that?

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Sometimes that initial blast of shielding gas is enough to do that.

try tapping the pedal first to get argon flowing and get past that initial blast before lighting up.

if your machine has a preflow setting, set it to a half a second.