I did a search and could not find anything so here is my question....
I just bought a MM180 with auto set and love the thing, when i weld it will be fine but right at the end of the weld it starts to grow like some kind of mutant weld. When i grind the "mutant" weld its hollow inside so its kinda like a bubble.

All my metal is clean new metal, its not rusty or oily or anything...
Thanks for any info everyone.
Ken