How can sanding scratch swelling be prevented?

• A. Using proper sanding techniques and grit progression
• B. Applying more primer
• C. Using only fine grit
• D. Skipping sanding steps

Answer: (A)

Preventing sanding scratch swelling comes from how you sand the surface. Use a proper sanding approach with a progression of grits rather than jumping to a fine grit or skipping steps. Start with a coarse enough grit to remove the deepest scratches, then move to progressively finer grits to smooth and feather the area. This keeps scratches shallow and evenly blended, so there aren’t raised ridges that can swell once primer or paint is applied. Dry sanding or over-sanding can create or reveal defects that lead to swelling, while simply adding more primer won’t fix the underlying scratch pattern. If possible, use wet sanding to reduce heat and keep the surface cooler, but the key idea is controlled sanding technique with a proper grit progression to achieve a smooth, uniform substrate.