Answer
For motorcycle fairings, use 400 or 600 before primer or paint. Use 320 only on rough repairs.
Why it happens
Fairings are usually plastic or painted plastic, so they need a fine scuff pattern before primer or paint.
Recommended grit
Use 400 or 600 for paint prep. Use 320 only for rough repaired spots.
Wet or dry
Dry for prep; wet can be used at finer stages.
Success check
The fairing is clean, dull, and evenly scuffed.
What to do
- Clean the fairing.
- Sand repaired rough spots with 320 if needed.
- Scuff the full paint area with 400 or 600.
- Clean dust and residue before primer or paint.
Avoid: Do not use coarse grit across visible fairing panels before paint.