What grit sandpaper is used for final sanding before primer?

• A. 180-320 grit
• B. 36-80 grit
• C. 1200 grit
• D. 80-120 grit

Answer: (A)

When preparing a repaired surface for primer, you want a grit that creates enough tooth for the primer to grab onto, but doesn’t leave deep scratches. A medium-fine range, specifically 180 to 320 grit, hits that sweet spot. It smooths out high spots and feathered edges from bodywork while still providing a mechanical key for the primer to adhere to.

Using something coarser, like 36–80 or 80–120 grit, would leave noticeable gouges that require more filler or filler rework and can lead to an uneven finish. On the other hand, an overly fine grit like 1200 is too smooth and would not give the primer much to grip, potentially compromising adhesion and leaving a less uniform surface.