Answer
Start with 120 or 180 for rough metal, then step through 220 and 320.
Why it happens
Burrs, oxidation, or deeper scratches need a grit that still cuts them.
Recommended grit
Start around 120 or 180 for roughness, then 220 and 320.
Wet or dry
Dry for initial prep; wet for finer stages.
Success check
The metal feels even and the scratch pattern is consistent.
What to do
- Remove loose debris.
- Sand with a grit that cuts the roughness.
- Step finer gradually.
- Clean before final inspection.
Avoid: Do not start too fine on rough metal.