The LH rear fenderwell had some rust all along the fender interface...some of which was on the exterior above the fenderwell and had progressed to inside of the bed. I ordered a patch panel for the external portion since it was available.
I cut out the rusted areas on the fender and fenderwell and treated the inner rust while it was open. I did not address the rust on the bed at this point since the area would require a bead rolled panel. I then welded in the patch panel on the fender.
The patch panel did not include the substructure in the fenderwell so I had to fab that portion from sheet. I made a simple wood buck out of a 2x8 or 2x10 that I had laying around to make the upper fenderwell portion. I had to temp install the new upper fenderwell with sheet metal screws and bolt the rear fender to it so I could locate the weld nuts that are welded to the upper fenderwell before welding it in place.
The RH side was in a little better shape. The fender was in good shape but the fenderwell was rusted so I used the same wood buck and process to replace this area.
1949 Chevy Panel Truck A Project Journal I'm old but I make up for it by being immature.