Getting a Perfect Varnished Finish
- Before using polyurethane varnish, seal the surface with one coat of varnish diluted by 10% with white spirit. Use a soft cloth pad to work the varnish into the grain, and a brush to get into corners and mouldings.
- Before applying a wax finish, seal the surface with a diluted coat of varnish.
- All brushes must be clean, as any old paint clinging to the bristles might spoil the finish.
- Tap excess varnish from the brush. Make sure you don't squeeze or scrape the brush against the tin, as this can create air bubbles in the varnish.
- Whichever finish you are using, allow each coat to dry completely and rub down with fine sandpaper or wet-and-dry paper before applying the next coat.
- If, prior to the last coat of any finish, there are imperfections - such as dust, stray bristles, or runs - remove these with wet-and-dry paper when the surface is completely dry, dust, then apply the final coat.
- If dust settles on the surface you have been working on while the last coat is still wet, let it dry, then use the back of some sandpaper, wrapped the wrong way round a sanding block, to clean off the dust without scratching the surface.
If you want a smooth, gloss finish on an open-grained wood such as oak, ash, or elm, use grain filler. Choose a filler that matches the wood colour, adding a few drops of dye if necessary. Apply one coat of varnish first, and allow to dry. Brush the filler into the wood, working with and across the grain. Remove the excess with a coarse cloth. Lightly sand with the grain when fully dry.
