Answer
For zinc-plated hardware, scuff lightly with 400 or 600 only. Do not sand through the plating.
Why it happens
Plated hardware has a thin surface layer. Aggressive sanding can expose bare metal and increase corrosion risk.
Recommended grit
Use 400 or 600 only for light scuffing before paint.
Wet or dry
Dry.
Success check
The surface is lightly dulled without exposed bare spots.
What to do
- Clean the hardware first.
- Scuff very lightly with 400 or 600.
- Avoid sanding through the plating.
- Prime or coat promptly after prep.
Avoid: Do not use coarse grit on zinc-plated hardware.