I got the bumper mounting brackets TIG welded to the inside of the bumper yesterday. The JB Weld and Bondo I had applied handled the heat of welding, the original paint near the weld locations was cooked, so I set about sanding off most of the original paint, then applying another skim coat of Bondo to the JB Weld filled holes and block sanding. When I was satisfied with the finish, I thoroughly degreased and dried the inside of the bumper then sprayed gray primer. After a 1 hour dry, I flipped the bumper over and used jack stands (with folded microfiber clothes taped on to protect the fresh paint on the inside of the bumper) to hold the bumper off the floor, thoroughly degreased and dried the outside of the bumper then sprayed 3 coats of gray primer (first - light dust coat, then 2 medium coats).
Next, off to the body shop to get the outside of the bumper painted in GP white.
TIG welded mounting brackets
Bumper prior to block sanding Bondo:
