The wood grain should not be sanded too fine. 150 grit sandpaper is fine enough. Sanding too fine will polish the surface and close the pores, thus making it hard for oil to penetrate. Do all your sink cutouts, backsplash, drilling, and sanding before starting the finishing process. A great all-natural finish is 100% Pure Tung Oil and Citrus Solvent. Pure Tung Oil comes from a nut like a walnut, however, because it is a drying oil, we have not found that it causes allergic reactions such as non-drying nut oils, like peanut oil.
Pure Tung Oil should be safe for all food contact wood finished products. Because Pure Tung Oil is a high solid oil, it does not penetrate dense wood well on its own. We recommend cutting (thinning) the oil with a natural solvent called Citrus Solvent. The Citrus Solvent is a natural product from the orange juice industry collects from the peel of the orange.
This makes a perfect, natural thinner to help Pure Tung Oil absorb into the wood. Mix the Pure Tung Oil and Citrus Solvent one to one or 50/50. We also have a pre-thinned version called ” Half & Half”. A ready-to-use version so you do not need to buy separate products. Apply the mixed Tung Oil and Citrus Solvent with a brush over the whole surface. Apply coat after coat and feed the wood cells. Picture a dry sponge. Wood has open cells just like a sponge. The sponge is most absorbent when it is dry. The wood will absorb the oil till it is saturated. Feed the wood until it will not accept any more. Then wait 40 minutes to an hour and look for dry spots. Feed the dry spots. Keep feeding the Pure Tung Oil and Citrus Solvent until the wood stays uniformly glossy. This may take several hours. When the wood will not take anymore and the mixture sits on the surface, now is the time to wipe all excess oil off. Use firm pressure and wipe all standing puddles and loose oil off the surface. You are done for the day. (Day 2) Feed the wood again until it puddles. Let the 50/50 mixture sit on the surface to penetrate when it seems no more will absorb wipe off the excess.
Watch the wood countertop for seeping over the next 5-7 days. Wipe off any oil that comes to the surface with clean rags. Lightly buff the surface for the next week or so to ensure no oil that may seep up to the surface is allowed to cure there. Pure Tung Oil takes 15-30 days to fully cure. During this curing period, you can use the countertop more and more as the oil begins to cure. For the first 7 – 1o days, keeping all objects off the surface is best. If any liquids do find their way onto the surface, immediately wipe them up. You can use parchment/wax paper around sinks to keep water off the countertop while using the sink. Simply remove the parchment/wax paper when you’re finished using the sink. After 10-20 days, it’s ok now to leave objects on the surface. You’ll still want to avoid letting water or sweaty glasses rest on the surface for long periods of time. After 30 days your countertop is fully cured and is ready to take the full abuse of a kitchen.
If you have an end-grain countertop, you can apply the Pure Tung Oil straight or uncut to these surfaces. Especially the exposed end grain of the sink cut out. Wood end-grain is like a stack of straws on the end. All the little tubes sticking up. This is very absorbent and will drink up the pure oil. You want to fill up these end grain tubes full of oil.
For under the counter, you can do one or two coats of 50/50. Two coats are plenty. Coating the underside helps to even out the absorption of moisture into the wood and slows down expansion and contraction. To maintain the countertop, make a solution of 2 parts Citrus Solvent to 1 part Pure Tung Oil. Apply this real thin with a rag. Do this maintenance coat when you feel the wood is dry and absorbing water from cleaning. Maintenance coats should be allowed to dry a day or two. Then you can go back to full use again.
All of the instructions here also apply to the Dark Raw Tung Oil. We make Dark Raw Tung Oil be a stain finish in one. All are non-toxic and environmentally safe.
Put used rags outside and hang them up to dry before disposing of them in the trash.