Using a Tung Oil Finish
There are many ways to clear coat your project but if you have the time and plenty of elbow grease, a tung oil finish is hard to beat for achieving a deep clear luster, durability, repair-ability and ease of application. Follow these simple steps and I’m confident you will be happy with the results.
Sand, sand, then sand some more. Remember I mentioned elbow grease, you will need it now. I sand up to 320 grit with a random orbital sander then begin sanding by hand, finishing with 400.
Make sure all swirls and scratches have been removed by using a magnifier, I wear a Bausch and Lomb visor throughout the entire sanding process looking for hiding scratches. If you don’t get those scratches now, they will haunt you and become accentuated as you apply successive coats of oil and will be difficult to remove, you do not want to go backwards at this point. Once the sanding is finished, clean, buff and polish all surfaces with a soft, clean rag free of buttons, stitching or any other hard foreign matter that would scratch.
One could begin to apply tung oil at this point, I prefer applying a coat of wax free shellac prior to the oil to seal the wood. The first coat of oil over shellac looks like the third coat of oil over bare, raw wood, it’s a bit of a head start. Be very careful not to over apply the shellac, put it down and move on. Over applied areas can be carefully sanded level before applying the oil or stain. Apply in small areas and have a plan before you start the application. Once dry, sand lightly with 320 grit followed by very fine steel wool, then buff and polish.
Often times, there is color variation within the wood so at this point, I apply two coats of wiping stain to make the piece much more uniform in color. A shellacked surface is a wonderful sub surface for stain because it controls variation of stain absorption, making for a much more uniform finish. When completely dry, buff and polish.
Apply the first coat of tung oil with a soft clean rag, working in small areas. Wipe immediately, tung oil dries fast and will become sticky, remove all oil and allow to dry 24 hours before the next coat. Never put your project in the direct sun to dry, the oil will heat and expand, oozing out of the grain only to dry as little pimply bubbles. After every 3 coats or applications, stop and lightly sand with 400 grit and very fine steel wool to keep the surface smooth and level, then buff and polish with a smooth rag before the next coat. Don’t rush the applications, It’s very important to allow the oil to dry for 24 hours between coats to harden. The way the finish develops it’s wonderful deep sheen is by vigorous buffing and polishing between coats and the oil must be hard and dry, otherwise, it will scratch. By now, you should be using plenty of elbow grease and clean, soft rags.
The beauty of the tung oil finish is you can put down several coats and it will never cloud but only become deeper, 10 or more coats and a couple of weeks is not uncommon.
Once you have achieved the desired depth and sheen, allow to cure for several days before applying two coats of wax. The main ingredients for a great tung oil finish is plenty of time and elbow grease.