The following pics show how I dismantled my 1930 coupe body completely and then had the individual panels chemically rust stripped.
After stripping, the panels were e-coated, which is also known as elpo. This is an immersion process and involves a 7 step electrolytic paint process which coats the part with an epoxy primer which is baked at 400 degrees F.
This e-coat primer is essentially bulletproof, and all the bondo work can be done on top of it, and then additional primer and top coat can be applied over the bondo. It will accept any type paint, urethane, enamel, lacquer, etc.
This type of stripping and finishing is readily available in the midwest and Detroit area due to the OEM automotive presence here. This is the same finish which comes on new Ford service parts like doors, hoods, oil pans, etc.
I made this cage from expanded metal to protect the panel in handling at the stripper and the e-coater. Works great. I did the LH and RH sides on separate trips since I did not want to make two cages.
Inside after stripping.
Outside after stripping.
I also did all the other parts shown in the pics below, including the cowl, doors, rear window opening panel, and deck lid.
This pic shows the body being reassembled with the individually coated panels. After final assembly any bondo and then paint are applied.
Coming together!