Answer
Use 80 or 120 for heavier rust, then refine with 180, 220, and 320 before coating.
Why it happens
Rust removal needs a grit coarse enough to cut oxidation before the surface is refined.
Recommended grit
Use 80 or 120 for heavier rust, then 180, 220, and 320 for prep.
Wet or dry
Dry for initial rust removal.
Success check
Loose rust is removed and the metal has an even prep pattern.
What to do
- Remove loose rust and debris.
- Start with 80 or 120 for heavier rust.
- Step through 180 and 220.
- Use 320 for smoother prep before coating.
Avoid: Do not start with ultra-fine grit on heavy rust.