It seals the bare metal, helping to stop the spread of rust. When filler is applied over bare metal, rust will form between the metal and the filler over time, it just helps with the longevity of the repair, especially if the car is not garaged regularly.
Rt frt fender skimmed about 1/8" thick all over with bondo over clean bare metal in 1983 due to damage. No epoxy. Repair is still good till this day even though I replaced the fender with a better one because of the rust in the lower fender from dirt in the reinforcement.
That makes me feel better...and my Maverick is garaged and never driven in the rain plus it's pretty dry here in AZ....LOL
More pics Metal work is done and the body work has started...here are just a few pics. Should be in primer by the end of this week.
Final Primer - Color Next! Here are some updated pics of the car in the final primer stage. Color should be going on next.
You said in an earlier post that you are going to paint the car orange. Is Calypso Corral the color that you are using?
I thought the same thing. Wish I could say the same, my hood was "repaired" at some point and the only rust through it has are pin holes from where moisture got under the mud. Mine will get the primer then the mud.