What’s the proper sanding and wet-sanding grit progression to finish gel coat before buffing?

1. Confirm cure & film build: Only sand fully cured gel coat. If the film is thin (e.g., small repair), start with finer grits to avoid burn-through.
2. Level the texture (optional dry sand):
   • Light orange peel / dust nibs: Start at 600 (wet).
   • Moderate orange peel: Start at 400 (dry) then switch to wet 600.
   • Heavy peel / runs: Spot-level with 320–400 (dry) on a hard block, then proceed to wet 600.
3. Wet-sanding progression (do not skip steps):

   600 → 800 → 1000 → 1200 → 1500 → 2000 (or 3000 if you prefer a faster polish). Use clean water with a drop of soap, keep the surface flooded, and squeegee often to inspect.

4. Compounding:

   Use a rotary buffer with a wool cutting pad and a quality marine cutting compound. Work at low-to-medium speed (about 1200–1800 RPM), overlapping passes until sanding marks are removed. Keep pads clean and the panel cool.

5. Polishing:

   Switch to a foam polishing pad and a finishing polish to remove any haze and boost gloss. Wipe residues with clean microfiber.

6. Protect:

   After the finish is dialed in, apply a sealant or marine wax (follow product cure guidance).

Tips: Use a guide coat to spot low/high areas, sand edges lightly, change paper frequently, and avoid heat buildup. If you expose substrate or sand through, spot-recoat and re-level after cure.