The growing weld

[kuziken]

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

[fabricator]

oxygen contamination. could be wrong gun angle,not enough sheilding gas,too far out with nozzle.

[tacmig]

When finishing your weld do you simply stop or do you back weave? If your bead run is good than your settings are probably good.

[kuziken]

back weave? sorry i dont know what that is. and yes when i come to the end of my weld i do just stop. should i turn the gas up? im running at bout 20.
ken

[canadiandiver]

If you don't keep the Mig bead moving when you stop there is a mutant bubble.

[Craig in Denver]

back weave: when you get to the end of the bead, don't quit. Reverse direction and weld back over your bead about 1/2".

[tacmig]

If you just stop you're going to see this happen, I don't have to explain the back weave as Craig in Denver summed it up pretty good. In addition to your back weave, pull your gun away at the opposite direction with a flip of your wrist.

Hope this helped.

TacMig