Answer
For metal, use 120 or 180 for rough prep, 220 and 320 for smoothing, then 400 or 600 for finer prep.
Why it happens
Metal prep needs a grit coarse enough to remove oxidation or scratches, then finer grits to refine the surface.
Recommended grit
Use 120 or 180 for rough prep, 220 or 320 for smoothing, and 400 to 600 for finer prep.
Wet or dry
Dry for rough prep; wet for 400 grit and finer finishing stages.
Success check
The metal has an even scratch pattern and no rough spots.
What to do
- Remove loose dirt, oxidation, or residue.
- Start with 120 or 180 for rough metal prep.
- Move through 220 and 320 to smooth the surface.
- Use 400 or 600 for finer prep before finishing.
Avoid: Do not start with ultra-fine grit on rough or rusty metal.