Tung oil is used as a finish for new or antique furniture to achieve a hand-rubbed look. A tung oil or Chinawood oil finish is usually applied to unfinished wood, but works just as well over a wood stain. Tung oil has a warm, amber color that gives wood a classic hand-finished look. Tung oil does not create a layer over the wood like varnish, it is absorbed by the wood to create a durable seal that is easy to maintain. It can be used on both indoor and outdoor furniture.
Prepare the wood surface by sanding with a medium grit sand paper. Switch to a smooth grain once all the surface blemishes have been removed. Always sand in the same direction as the grain. Make sure the surface is completely smooth, as tung oil is absorbed into the wood and will not smooth over slight imperfections like varnish will.
Repair any holes or cracks in the surface by filling with a wood filler. If you intend to use a stain, make sure the wood filler will hold the stain. Sand the wood filler down. If you do not intend to stain the wood, ensure that the wood filler matches the wood color. Once the final sanding is complete, wipe all wood surfaces with a rag to clear dust.
Thin the tung oil by mixing it in equal parts with mineral spirits or turpentine. This will facilitate absorbtion into the wood, reduce drying time and produce a more desirable finish. Apply directly to the wood surface with a soft cloth. Rub the tung oil into the surface until the wood is saturated. For hard to reach places, use a brush with natural fiber bristles.
Dry the wood between coats. This is a lengthy process that takes 24 to 48 hours, depending on the porosity of the wood. Lightly buff the wood with steel wool between coats. Apply three or four coats of tung oil to achieve a waterproof seal and up to six coats for new or porous woods such as cedar.