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Epoxy Primer Versus Self-Etching Primer:
Which One is Better for You?

Two kinds of bare metal primers are used in car body shops: Epoxy primer and self-etching primer. Both provide corrosion protection but depending on the condition of the car’s metal surface, one might be better to use than the other.

This article will help you decide which to use on your vehicle painting project.

Epoxy primers / sealers

An epoxy primer acts as a sealer to protect the vehicle surface from the harsh environment and contamination. It is applied after sanding the surface with 80 to 180-grit sandpaper. Epoxy primer is acid-free, which helps prevent chemical lifting issues. Apply it over bodywork, sanded paint, or metal. This makes it an excellent choice for restorations that use body fillers.

The advantages of epoxy primers:

  • Unlike self-etching primers, epoxy primers are acid-free and less likely to lift chemicals to the topcoat.
  • Epoxy primers can be applied over bodywork, sanded paint, or metal.
  • Body filler can be applied over epoxy primer.
  • Epoxy primer has excellent adhesion, forming a strong bond that prevents rust.

Self-etching primers

Self-etching primers use acid to chemically clean and etch the vehicle’s metal surface. These primers are ideal for use on smooth, rust-free metals.  They require very little turn-around time. Only a thin coat is needed on metal surfaces. Because self-etching primers dry quickly, they are often used at busy collision shops with high levels of turn around.

Here are some advantages to using self-etching primers:

  • They provide excellent adhesion over different metals.
  • They dry faster than epoxy primers and can be applied shortly after primer application.
  • Minimal surface preparation is needed. Simply clean and degrease the area, making sure the metal surface is smooth with no rust.
  • Self-etching primers are available in spray cans, making them perfect for small areas of vehicles that need corrosion protection.

Whichever type you choose, bare metal primers will prevent rust or corrosion on the surface of your car.