Repairing galvanic corrosion holes
I have been researching "aluminum body panel repair" on the internet and stumbled across this site. I am hoping someone can tell me the proper way to repair holes caused by galvanic corrosion (which will be painted). What I have learned so far is:
1. Drill;, rasp; or otherwise (but do not grind) to remove the aluminum which has oxidized to a white powder all around the perimeter until the hole has a 'solid' aluminum edge.
2. Prime the cleaned hole w/ a zinc chromate primer.
From this point forward I have several choices:
3 a. Cover the cleaned and primed hole with 3M aluminum autobody repair tape and spread, sand, and feather a plastic (or aluminum powder based) autobody filler in successive layers; or b. Spread a layer of autobody filler, imbed a piece of aluminum or fiberglass screen and squeege flat. After the filler has cured, rough sand w/ #80 paper to a level surface at the edges. Successive layers of filler can be added and sanded until the entire surface is level and feathered into the surrounding area.
4. Final sand the patch with #320 wet paper to remove any scratches; prime with a sandable automotive primer; lightly dry sand with #320, blow off dust; clean the area with an automotive refinishing degreaser; and tack rag the surface to remove any stray dust particles before applying the finish coat(s).
Any first-hand recommendations as to proceedures, materials, etc. are greatly appreciated.