How are self-etching primers generally designed to be sanded?

Self-etching primers are specifically formulated to create a chemical bond between the substrate and the primer itself, which makes them distinct from traditional primers. While some primers might be sanded to achieve a smooth surface, self-etching primers typically do not require the same aggressive sanding process. They are designed to enhance adhesion without the need for heavy sanding.

The correct approach involves lightly sanding if necessary, which helps promote better adhesion for subsequent layers of paint, without compromising the chemical bond established by the primer. This careful sanding prevents damage to the primer layer, maintaining its effectiveness while also providing a surface that can be painted over. Thus, the optimal method of preparing self-etching primers for paint application is indeed to sand them lightly, as this retains their structural integrity and performance.