FAA AMT Airframe Test 2025 – 400 Free Practice Questions to Pass the Exam

A wash primer is a type of coating that includes phosphoric acid as one of its components at the time of application. Phosphoric acid helps to etch the metal surface, providing better adhesion for the subsequent layers of paint or primer. This type of coating is commonly used in aviation maintenance to ensure a strong and durable bond between the metal surface and the paint or primer.

On the other hand, the other options are incorrect because they do not contain phosphoric acid as a component at the time of application. Epoxy primer, acrylic enamel, and latex paint have different formulations and do not utilize phosphoric acid for surface preparation and adhesion like wash primer does.