Answer
Patchy finish often means the previous grit marks were not fully removed. Go back one grit, sand until the scratch pattern is even, then move finer again gradually.
Why it happens
Uneven sanding pressure, skipped grits, or moving on too early can leave mixed scratch patterns that absorb finish differently.
Recommended grit
Return to the last grit that leveled the surface, then move forward one step at a time, such as 180, 220, 320, and 400.
Wet or dry
Use dry sanding for most finish prep. Use wet sanding only on water-safe finishes or surfaces.
Success check
The whole surface has the same final scratch pattern and the finish no longer absorbs in patches.
What to do
- Identify where the finish looks patchy or uneven.
- Sand a small test area back with the previous grit.
- Use even pressure and overlap your passes.
- Continue until the scratch pattern looks consistent.
- Move to the next finer grit only after the surface is even.
- Clean dust before applying finish again.
- Use a consistent final grit across the whole surface.
Avoid: Do not spot-sand one area to a much finer grit than the rest. It can make the finish absorb unevenly.