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rw7810
01-22-2007, 01:02 PM
What causes the dimple in spot welds. Almost every one I do ends up with one. When ground down, most of the time there seems to be a small bubble or void under it.

PS: other than that, and a few burn throughs on sheet metal, I'm having a blast with my new MM175.

88GT
01-22-2007, 02:16 PM
Sounds like an argon problem. If the nozzle is dirty, the gast too low, or wind or a fan is blowing the gas away it will do that. I usually close the shop door if it's windy and point the fan away from me when welding

TimG
01-22-2007, 11:06 PM
Also,any rust,paint,etc.on the weld surface will either give you a "volcano" of weld,or a bunch of tiny holes.
I usually grind to bare metal an inch or so around where I'm going to plug weld on both the new part{both sides} and the top of the piece I'm welding to,then apply weld thru primer to the bottom of the new part,and the top of the old.
Not all weld thru primers are equal,I've tried some off brand stuff that is AWFUL!!!!
I like the Upol,pretty sure Len sells it.
Also,make sure your wire is clean and not rusted,and no grease or oil on the feed rollers.
Wrong type of gas will do it too,steel mix is 75% Argon,25%Carbon Dioxide.
Good Luck!

rw7810
01-23-2007, 11:00 AM
Thanks guys, pretty much answers it. I was cleaning my weld areas, but not the back sides of the weld to pieces. Also wasn't using the weld though primer but I probably should have.