How to Add Varnish to a Wood Desk

Remove the drawers and any hardware that are on your desk. Place the hardware in a plastic zipper bag to keep it safe if you want to replace it after varnishing. Throw it away if you are buying new hardware.

Sand all the visible surfaces of the desk. Sand the top, front, sides and the front of the drawers. Use 100-grit sandpaper at first to remove most of any old varnish or stains.

Use a damp rag to wipe off the wood after sanding. Remove all traces of the sanding dust. Allow the wood to dry for 30 minutes.

Sand again, this time using 220-grit sandpaper. Sand until the surface of the wood is as smooth as possible. Wipe with the damp rag and allow it to dry for 30 minutes.

Brush on a thin coat of the varnish using a soft, natural bristle paintbrush. Move the brush strokes in the same direction as the grain of the wood. Go from one side of the desk to the other without lifting the brush for best results.

Allow the varnish to dry for a few hours to overnight. Check the manufacturer's suggestions for drying times as these will vary from brand to brand of varnish.

Sand lightly with 320-grit sandpaper. This slightly roughens up the one coat of varnish and helps the next coat to adhere better. Wipe with a damp rag. Allow the desk to dry for 30 minutes.

Add the second coat of varnish in the same manner as the first. Keep sanding between coats and adding more varnish until you have the desired gloss on your desk.

Allow the varnish to cure for about seven days before adding hardware and sliding the drawers back into your desk.