I have some deep scratches on my fender that I filled in with Bondo glazing putty. Feels pretty smooth. I'm planning to spray on a filler primer and sand it down this weekend before spraying the urethane paint I bought to match.

The paint supplier said I should apply a sealer after the primer. Is this a necessary step and what exactly is sealer and is there a recommended type for this job?

  • What kind of primer did you use and what type of paint to plan on using? Feb 13, 2016 at 1:59
  • It's a urethane paint that I plan to spray with my hvlp gun. The primer I bought is just a can of Rustoleum auto primer filler (red). Feb 13, 2016 at 14:36

1 Answer 1


Professional painters prefer to use primers, sealers, color coats and clearcoats all from the same manufacturer and paint family. This ensures compatibility and long paint life. The second layer after the primer is usually an epoxy sealer. This is the layer that is the last defense against corrosion and it is very effective in this roll. Since you already have the Rustoleum primer why not use their primer sealer product. If this is a small area the more expensive epoxy type sealer is not likely to provide a high benefit.

  • Btw.. this is what I ended up doing (Rustoleum primer + Rustoleum primer sealer).. Been almost a year and holding up great! I used a different brand clearcoat (2K)... expensive, but it did a fantastic job Jan 12, 2017 at 21:15

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