Answer
For metal paint prep, remove rust or old coating with 120–180 if needed, then finish with 220–320 before primer. Use 400 for finer prep on smoother metal.
Why it happens
Metal prep needs enough tooth for primer while still removing rust, oxidation, or old coating marks.
Recommended grit
Use 120–180 for rust or old coating cleanup, 220–320 before primer, and 400 for finer prep on smooth metal.
Wet or dry
Use dry sanding for most bare metal prep. Use wet sanding only when the metal will be dried immediately to prevent flash rust.
Success check
The metal is clean, dry, evenly abraded, and ready for primer or paint.
What to do
- Clean grease or residue from the metal.
- Use 80 only for heavy rust or thick old coating.
- Use 120 or 180 for normal rust or coating removal.
- Move to 220 to reduce removal scratches.
- Finish with 320 before primer on most metal prep jobs.
- Use 400 when a finer scratch pattern is needed.
- Remove all dust and dry the metal before coating.
Avoid: Do not leave bare metal wet. Dry it quickly to reduce flash rust before primer.