1966 F100 Short Bed Styleside Metal/Body/Paint Work in Our Cars & Restoration Projects Posted September 9 2 hours ago, ChuckMcChuckles said: I hope your parents are doing better. I noticed you are applying filler over epoxy. Which is better -filler applied over bare metal vs painted metal? Thanks, mom is almost back to normal and dad still has a cough but the other symptoms have cleared up. I always shoot two coats first to seal the bare metal 100%. If the paint was ever damaged to the point that the filler becomes exposed there is still epoxy under the filler to protect the metal in case the damaged filler gets wet (filler is porous and will absorb water). Another reason to do epoxy first- epoxy sticks to bare metal really well. Filler likes a rough surface to stick too, and I would rather not grind the metal that hard (36-40 grit is often used) to roughen it appropriately. I use SPI epoxy and it has a seven day window to top coat it with filler or other primers and they'll chemically bond with the epoxy with no sanding needed within the seven day recoat window. The pretty much guarantees 100% adhesion of the filler to the epoxy, or adhesion of the high build primer as long as you don't go over the epoxy too soon before it has started to cure enough- I like to wait at least 24 hours for filler or 4-5 days before high build primer. I always seal the filler with two more coats of epoxy before moving on to high build primer.