How to Darken Varnished Wood

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Varnish is the hard, glossy coat on top of wood finish. It protects the wood by sealing in moisture and providing a barrier against ultraviolet radiation. Wood can be darkened easily with additional coats of stain.

Wood that has been varnished will not absorb stain properly, so the gloss of the varnish must be removed with a deglosser to access the wood grain for stain application. This is best done with a chemical liquid sanding agent, also known as a chemical deglosser.

Apply the deglosser to the surface of the wood with a disposable paint brush. Allow it to sit for five minutes. Wipe the surface with a clean rag to remove the top layer of the gloss.

Allow the wood to sit for an additional two hours. Wipe the surface again with a clean rag to remove grime and finish that has broken down.

Sand the surface lightly with an emery cloth. Wipe the dust from the wood with a tack cloth to prepare for the stain. Rinse the sander from the surface by wiping with a rag dampened in odourless white spirit. Allow the wood to dry for one hour.

Shake the stain can well to mix in the solids and remove the lid. Allow it to sit until no visible bubbles rise to the surface. Dip a soft bristle paintbrush into the stain, about 1/3 the length of the bristles.

Apply the stain to your wood with the brush, working with the grain in long straight strokes. Overlap your strokes for adequate coverage, working to spread it as evenly as possible to prevent runs and drips. Wipe excess stain from the wood with a clean, lint-free rag. Rinse the brush in lacquer thinner.

Allow the stain to dry according to the label instructions, and check the colour. Reapply stain a second time if the wood has not darkened as much as desired. Wipe the excess from the wood as before, with a clean rag. Allow the stain to dry. Rinse the brush in lacquer thinner.

Reapply a coat of varnish with the paintbrush, working in long, slow strokes. Avoid reworking areas to prevent brush strokes. Apply the varnish in a medium thick coat, working slowly to prevent bubbles. Spread the varnish evenly to prevent runs and drips. Wait 24 hours before returning the piece to normal use.