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.
Fiberglass sheet metal repair.
Typically fiberglass is used for rust repair by replacing the rusted metal and sealing the surface.
Power fiber body filler for repair and reconstruction of fiberglass smc sheet moulding compunds parts metal sheet and wood integrating adhesion promoters plasticizers polimeric elements short strand fiberglass and micro fiberglass.
I then used the templates to trace out the patch panels on some sheet metal.
Scuff the entire area removing any loose or damaged metal down to solid metal.
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.
I used a piece of pvc pipe a vice mount miniature metal break and body hammer kit.
Air bubbles reduce bond and will expand with heat causing future problems.
Fiberglass rust repairs are easily available at all local auto body supply store.