I would recommend sanding all the bare metal with 180 grit to get it ready for the Epoxy. Then wait at least 2-3 days before you start your body work for the primer to dry enough. When the time comes to apply body filler I would recommend sanding the surface with 180 grit sand paper. Then once you are done with the vehicle you can scuff the entire surface with a red scuff pad to get ready to move on to a high build primer. I hope this helps. Feel free to email anytime. [After repairs, re-spaying the epoxy would be] a perfect way to make sure that if you have hit any bare metal while doing the body work that you will have the panels protected.
SCOTT CHURCH Lead Tech Advisor
The Eastwood Company 263 Shoemaker Road Pottstown, PA 19464 Extension 5409