Why is scuff sanding utilized in the painting process?

Scuff sanding is an essential step in the painting process, primarily because it reduces the original gloss of the surface and enhances adhesion for the new paint layer. By lightly abrading the surface, scuff sanding creates a texture that allows the paint to mechanically bond better, leading to improved durability and longevity of the finish. This process is especially important when working with previously painted surfaces or glossy finishes, as a smooth surface can inhibit the adhesion of new paint.

In contrast, cutting deeply into the surface is not the goal of scuff sanding, as it could damage the substrate and affect the overall finish. Although scuff sanding can lightly dull a surface, it does not enhance the gloss; instead, it decreases it for better adhesion. Additionally, the practice does not eliminate the need for primer; in many cases, primer is still necessary to ensure proper bonding, especially on bare substrates or surfaces requiring extra preparation.