Answer
Sand between oil finish coats only after the coat is dry. Use 320 or 400 lightly.
Why it happens
Light sanding can smooth raised grain, but heavy sanding can remove finish or create uneven absorption.
Recommended grit
Use 320 or 400 lightly only after the coat is dry.
Wet or dry
Dry.
Success check
The surface feels smooth and clean before the next coat.
What to do
- Let the oil finish dry fully.
- Scuff lightly with 320 or 400 only if the surface feels rough.
- Remove dust completely.
- Apply the next coat thinly.
Avoid: Do not sand wet or sticky oil finish.