Answer
For galvanized metal before painting, clean first, scuff lightly with 220 or 320, then use 400.
Why it happens
Galvanized metal needs cleaning and light scuffing without removing too much coating.
Recommended grit
Use 220 or 320 for light scuffing, then 400 for smoother prep.
Wet or dry
Dry.
Success check
The surface is clean, dull, and ready for the proper primer.
What to do
- Clean the galvanized surface thoroughly.
- Scuff lightly with 220 or 320.
- Use 400 for smoother visible areas.
- Remove dust before primer or paint.
Avoid: Do not grind off the galvanized coating unnecessarily.