Answer
For most paint prep, use 220–320 for shaping and primer prep, then 400 before paint. Use 600 when the paint system needs a finer final scratch.
Why it happens
Paint prep needs enough scratch for adhesion, but scratches that are too coarse can show through the coating.
Recommended grit
Use 220–320 for prep and leveling, 400 before paint, and 600 for finer final prep when needed.
Wet or dry
Use dry sanding for most paint prep. Use wet sanding only on cured, water-safe coatings and surfaces.
Success check
The surface is clean, evenly scuffed, and free of visible coarse scratch lines before paint.
What to do
- Clean the surface before sanding.
- Use 180 only for rough areas that need more leveling.
- Use 220 or 320 for normal prep and primer smoothing.
- Move to 400 before paint on most surfaces.
- Use 600 for a finer final surface when the coating system calls for it.
- Remove sanding dust before painting.
- Inspect under good light for remaining coarse scratches.
Avoid: Do not paint over coarse scratches that are still visible. Paint can make them easier to see.