Red Seal Automotive Refinishing Technician Practice Exam

What should be done to a sanded surface prior to applying paint?

1. Apply a thick primer layer

2. Leave the surface as is

3. Clean the surface to remove dust and contaminants

4. Sand the surface again for better adhesion

The correct answer is: Clean the surface to remove dust and contaminants

Cleaning the surface to remove dust and contaminants is essential before applying paint. After sanding, a surface can accumulate dust, debris, or oils, which can interfere with the adhesion of the paint and lead to defects like peeling or uneven coverage. A thorough cleaning ensures that the paint will adhere properly to the substrate, providing a smooth and durable finish. Applying a thick primer layer is not a prerequisite; in fact, doing so without cleaning could trap contaminants beneath the primer, ultimately affecting the paint's performance. Leaving the surface as is disregards the importance of ensuring a clean substrate for optimal paint application. While sanding the surface again might help enhance adhesion, it is generally not necessary as long as the initial surface preparation was done correctly and cleaning is performed afterwards.