When you say sand the epoxy primer and put another coat on prior to the finish, do you mean scuff up the primer or sand it to bare metal again?
You can either use sandpaper or a scuff pad. You need to scuff up the surface, not sand to bare metal. You can use 400 grit if you are topcoating with a straight color or 600 grit if you are topcoating with a metallic.
Regards,
Steve
New Orleans
