How can runs be prevented?

• A. Applying heavy coats
• B. Skipping flash time
• C. Using faster thinner
• D. Applying even, light coats

Answer: (D)

Runs happen when a film is laid on too thick or when solvent hasn’t begun to set before more paint is added, so gravity drags the wet layer downward. The best way to prevent this is to apply even, light coats and build up the finish gradually. Thin coats dry more uniformly and let the solvent flash off between passes, keeping the film thickness in check and reducing the chance of sagging or drips. Use a steady spray technique with proper distance, pattern, and overlap, and give each coat enough flash time to become tack-free before applying the next one. Heavier coats, skipping flash time, or using a faster thinner can cause other defects, whereas repeated light, even coats maintain consistent film thickness and stop runs from forming.