Scuff the entire area removing any loose or damaged metal down to solid metal.
Fiberglass sheet metal repair.
After slicing the patches out with a cutoff wheel next came the bending hammer and dolly session until the patches matched the holes and fit snug and flush into the flanged seat.
Fiberglass is a non corrosive material that can be used as reinforcement or as a repair patch on almost all surfaces including metal plastic and wood.
Air bubbles reduce bond and will expand with heat causing future problems.
I used a piece of pvc pipe a vice mount miniature metal break and body hammer kit.
Typically fiberglass is used for rust repair by replacing the rusted metal and sealing the surface.
I then used the templates to trace out the patch panels on some sheet metal.
Fiberglass rust repairs are easily available at all local auto body supply store.
Once the fiberglass is layed up it should immediately be rolled out with a fin or bubble roller to remove any air trapped in between layers or part.