How to Prep Woodwork for High Gloss Paint

High gloss paint hides nothing. It is reflective, which means light bounces off the surface and highlights every imperfection - every grain line, every scratch, every undulation in the timber underneath. This is particularly evident on softer timbers and surfaces exposed to natural or directional lighting. If the woodwork is not perfectly smooth before the first coat of paint goes on, the end result will show it. Here's how to prepare woodwork to a flawless standard using a specialist fine finish filler, so your high gloss paint looks the part.

Step 1: Prep – Sand, Stabilise and Prime

Start by sanding the timber thoroughly with medium-grit sandpaper (P120), working along the grain. Remove any raised fibers, rough patches, or surface marks. On previously painted woodwork, sand to a smooth, keyed surface. If there are any chips, teeth, or deeper damage, address those first with the appropriate filler before moving on to the fine finish stage.

Brush off all dust and wipe the surface clean. Any dust left on the surface will be sealed in by the filler and shown through the gloss.

If the timber is porous or absorbent, apply Wood Hardener to seal and stabilize the surface. Apply Wood Hardener directly to the affected timber using the brush supplied in the screw top lid. Work it liberally into the wood, paying particular attention to end grain and any areas where the timber is soft or rotten. It can be applied to dry or damp wood, but not soggy wood.

The timber must then be primed. Toupret Fine Finish Wood Filler is designed for use over primed woodwork, so apply a primer or undercoat, allow it to dry fully, and sand lightly with fine-grit paper to remove any nibs. This builds up the surface and creates a stable platform for the filler.

Step 2: Fill and Finish – Build a Perfect Surface

Fine Finish Wood Filler is a specialist product designed specifically for achieving ultra-smooth surfaces on interior woodwork. It has an exceptionally fine texture that fills grain, micro-imperfections, and surface marks that standard wood fillers may not reach. It is applied over primed woodwork rather than bare timber.

Apply a thin, even coat across the primed surface using a filling knife. Work along the grain in long, steady strokes with consistent pressure. The aim is to fill every pore and imperfection while leaving the minimum amount of material on the surface - you are creating a perfect skin, not building up thickness.

Allow to dry fully, then sand with fine-grit sandpaper (P240 or higher). Sand lightly and evenly along the grain. Check the surface in raking light after sanding. This reveals any imperfections that are invisible under normal lighting.

If there are any remaining imperfections - open grain, pinholes, fine scratches from sanding - apply a second coat of Fine Finish Wood Filler and sand again. On high-quality gloss work, two or three coats with light sanding between each is normal. Each coat builds a smoother surface than the last.

Fine Finish Wood Filler has a setting time of 1-2 hours; therefore, multiple layers can be applied over the day to achieve the mirror-like finish.

Once you are satisfied that the surface is perfectly smooth to the touch, remove all dust thoroughly. The timber is then ready for high-gloss painting.

From this stage onwards, the final result will depend on the quality and application of the paint. Applying several coats of a good-quality gloss paint should achieve the desired finish, while Toupret Fine Finish Filler will provide the ideal foundation for a smooth, professional result.