Looking for advice for spraying epoxy primer over e-coat. This is for the interior of a quarter panel replacement, so it doesn't have to be show quality. It just needs to protect from rusting up again. I've tested the e-coat with some xylene and nothing came off so I'm assuming it's good e-coat. My plan is to scuff with the maroon scotch brite pad and then spray it after cleaning. I saw somewhere that sanding paste is recommended as an intermediate step. I've never heard of the stuff until now and I'm wondering if it's necessary. Any tips would be welcome.