Patching A Pontiac GTO - Let’s Patch Things Up

[13] He also welded the backside of the trunk filler using the same method.

[14] After the welds were cool, Tony ground them flush with a 36-grit disc.

[15] He applied USC All-Metal aluminum-based filler over the ground welds to seal the joints.

[16] Next, he installed the quarter-patch panel and adjusted it to ensure it was lined up perfectly before temporarily retaining it with screws. Note the holes drilled into the panel in the flange area at the top and bottom.

[17] Tony did it so he could plug-weld the panel in place. To perform a plug-weld, the outer panel is drilled prior to installation but the inner one isn’t. Then the hole is filled in, creating a stronger union than a spot-weld.

[18] Here’s a typical plug-weld at the bottom of the panel. Tony will later remove the screw and weld up its hole as well.

[19] Yes, it’s ugly. Part of the area normally occupied by the inner wheelhouse is rotted out. Unlike the outer wheelhouse with its compound curves, Tony can repair this area by cutting a piece of 20-gauge sheetmetal and adding a gentle curve to it. Here you can see the relationship between the trunk extension and the quarter patch.

[20] Tony used plug welds to hold the new sheetmetal to the trunk filler and the quarter-panel patch.

[21] Here’s the quarter after spot-welding to create a continuous bead.

[23] Here are the ground welds at the upper joint…

[24] …and in the wheelwell.

[25] After stripping the rest of the quarter to bare metal, Tony used All-Metal on the weld joints. He’ll knock it down with 36-grit paper. (We know the plug welds on the bottom have not been ground yet.)

[26] He also applied it to the weld joints on the backside of the trunk filler and in the trunk along the seam where the existing quarter and the patch panel meet.

[27] Tony followed the All-Metal with an application of body filler because its easier to work with for a top coat, which he shaped with 80- and 180-grit papers on a 12-inch block. “The longer the block, the straighter the panel,” he says.

[28] He sprayed two coats of PPG urethane primer and a guidecoat. Next would be block-sanding with 320-grit, then 500, and finally 800 to prepare it for paint. However, our subject GTO needs additional body work in other areas before it’s ready for paint, but we took the process this far to show you a completed repair for this article.