Oil Finish Can Go Wrong on Walnut
I wanted to give some European walnut a very fine, soft finish. I tried tung oil, but the surface looks muddy and the sapwood has a yellowish tinge. Am I doing something wrong?
Peter Grundy, Grellingen, None
Pure-oil finishes such as tung oil aren’t a good choice for a wood like walnut. The oil penetrates enough to darken the wood quite a bit, particularly the end grain. That can be objectionable on a naturally dark wood like walnut.
The oil also obscures the wood’s character, making the subtle pinks, reds, yellows, and greens in the heartwood disappear. The sapwood, however, takes on the color of the tung oil, so it appears quite yellow.
To rescue the wood, I would sand or strip away the oil and try a very light (super-blond) dewaxed shellac. It will preserve the delicate colors in the walnut and leave a crisp, light appearance while adding an overall luster.
If you don’t want the finish to seem thick, use only two or three coats of shellac. Rub it out with 0000 steel wool if it has too much gloss. Then finish up with a light coat of paste wax.
Jeff Jewitt is a wood finishing expert. For more on this subject, see “Finishing Walnut.”