How to Finish Window Sills
- 1). Remove old paint with the paint remover product. Wipe the paint remover onto the surface and let it sit for a few minutes. Scrap the paint off with a paint scraper. Repeat as many times as necessary, especially for older window sills with several layers of paint.
- 2). Sand the wood with the 80-grit sandpaper. Do not sand against the grain of the wood. Followup the 80-grit sandpaper with the 120-grit sandpaper to provide a smooth finish before applying the sealer. Wipe off any sanding dust.
- 3). Apply the sanding sealer evenly to the wood surface. Allow the first coat to dry completely. Lightly sand with the 120-grit sandpaper to remove runs or air bubbles from the surface. Apply a second coat.
- 4). Apply an oil base or waterproofed paint to the window sill with a clean paint brush. Sand out any runs in the paint before applying the second coat.
- 5). Insert the caulk into the caulk gun and cut the tip off. Begin applying the caulk to the window sill and window frame joint. Spread evenly and allow 24 hours to dry. Apply the caulking only after the paint completely dries.
