When is sanding scratch swelling most likely observed?

When is sanding scratch swelling most likely observed?

• A. After painting
• B. Before painting
• C. During sanding
• D. During primer application

Answer: (A)

Sanding scratch swelling happens when the coating is still soft and solvent-rich, so it’s most likely to be noticed after painting. In a freshly applied paint film, solvents are still evaporating and the polymer is plastic enough to flow slightly. If a scratch is present, the edges around it can absorb solvent and puff up, making the scratch appear wider or deeper as the film swells. This swelling is temporary and usually subsides as the paint fully cures and the solvents escape. If you wait for proper cure time or sand only after the film has hardened, the swelling won’t be as noticeable.

Sanding scratch swelling happens when the coating is still soft and solvent-rich, so it’s most likely to be noticed after painting. In a freshly applied paint film, solvents are still evaporating and the polymer is plastic enough to flow slightly. If a scratch is present, the edges around it can absorb solvent and puff up, making the scratch appear wider or deeper as the film swells. This swelling is temporary and usually subsides as the paint fully cures and the solvents escape. If you wait for proper cure time or sand only after the film has hardened, the swelling won’t be as noticeable.