This morning I repaired a crack in the driver’s side door that had been caused by either the stress of the window pillar pressing outwards or the side-view mirror. In either case there was a crack in the metal that ran across the top of the door about three inches and then down the door another inch or so. I cleaned down to bare metal using a 3m Clean Strip disk prior to any welding.
I used a spring clamp to pull the metal together where it had cracked apart and placed one small spot weld at the corner of the crack to tack it back together tight. Then I placed several more spots across the top of the crack.
Then I ran spot welds downward and across until the entire crack had been mended. I went slowly and used only very short pulls of the trigger in order to keep the tacks small.
Then I used my 4 1/2″ angle grinder with stacked cutoff wheels in it to grind the profile of the spot welds flush. When the welds got close I switched from using the edge of the wheels to using the face in order to flatten them very close to the oringal metal.
The finished repair was barely noticeable and will require a minimal amount of filler.