What is Tung Oil? (Uses and Applications) (2024)

What is Tung Oil? (Uses and Applications) (1)

Tung oil is an extract from the tung tree, Vernicia fordii. The Tung tree is endemic to Myanmar, northern Vietnam, and southern China. Its country of origin is China, where it got its name from tong or tung. According to the writings of Chinese philosopher Confucius, tung oil became in use from 500 to 400 B.C. Its primary purpose was for waterproofing ships and boats.

What is Tung Oil?

Tung oil is a product of extracting oil from the seeds of Vernicia fordii. Farmers cultivated it as a wood finish about 2,500 years ago. The oil in the tung tree contains numerous fatty acids, such as 82.0 percent Alpha-eleostearic acid, 8.5 percent Linoleic acid, 5.5 percent Palmitic acid, and 4.0 percent Oleic acid.

These fatty acids contain a chain of linked carbon atoms with conjugated double bonds. They react to autoxidation and stimulate the cross-linking of the chain, causing the base resin to harden.

Tung oil is a sustainable, organic, and food-safe ingredient in wood finish. Its popularity is due to its efficient and quick-drying properties that increase the longevity of the wood. Professional woodworkers in the United States and other countries use it to enhance and protect the wood grain.

What are the Benefits of Using Tung Oil on Wood?

Tung oil is a natural wood finish that gives a protective finish on the surface without leaving a trace of toxicity. It is safe to use during and after application. It is a practical method of wood finish as it does not require regular maintenance. Unlike some wood finishes, tung oil does not cause the wood to turn dark, rotten, or infested with mold, even if it has prolonged exposure to moisture.

It is quick drying than linseed and other wood finishes. It is easy to apply and takes only a few hours to dry it. It leaves a long-lasting matte finish, adding depth and color to the woodgrain, which brings out the natural beauty of the wood. This quality of tung oil makes it ideal for a rustic or antique-looking finish on the home interior and furniture pieces.

Over the years, craftsmen, artisans, and carpenters have chosen tung oil in their projects due to its versatility. Aside from wood, it brings a protective and beautiful finish to metal, brick, stone, concrete, and bamboo surfaces. It is a popular finish for coating wood floors, rails, siding, decks, cabinetry, musical instruments, furniture, handmade toys, and decorative wood boxes.

Using pure tung oil offers tons of benefits to users, but finding a 100 percent extract could be challenging. You can tell the difference between pure or dark tung oil by looking at the outcome. Pure tung oil turns honey in color when it dries, while dark tung oil turns the wood surface rich and dark.

Pure tung oil does not contain distillates and additives, which make the surface less glossy or heavy. Depending on the manufacturer, dark tung oil contains PCB-free and non-carcinogenic resinous hydrocarbon. These chemicals are responsible for turning the wood finish darker after application.

Scrupulous manufacturers mislabel their products by marking them as tung oil, which is not. You must read the manufacturer’s label carefully and research the chemical composition. In the absence of 100 percent pure tung oil, woodworkers use polymerized or boiled tung oil.

Tung oil does not cause a yellow tinge on the wood surface in the long run compared to polyurethane, nitrocellulose lacquer, or linseed oil. The downside of tung oil is that it is prone to scratches, water rings, and stains. It is also costly! Pure tung oil is an excellent alternative to other wood finishes and drying oils.

Tung oil has a lot of benefits for users, but it also has imperfections. Let’s take a look at its advantages.

Pros

It is Eco-Friendly & Natural

Since tung oil is eco-friendly and organic, it offers a food-safe finish, making it a favorite finish in woodworking. The unique fatty acids in tung oil do not give off an obnoxious odor and harmful chemicals. The combination of different fatty acids improves performance without damaging the environment and your health.

Tung oil is free from allergens as it does not come from nuts. Although its other name is China nut, its extracts are from berries. The Vernicia fordii tree bears berries that look like nuts but are safe for your health.

Free of Discoloration, Molds, and Yellowing

Tung oil contains natural substances and fatty acids that protect the wood grain. Unlike linseed oil, tung oil gives resistance to moisture on the wood surface, even under wet conditions. Unlike synthetic and oil-based finishes, it does not discolor over the years and discourages mold growth.

It is Waterproof

Drying oils like tung oil do not dry and stay as oil after long years of use. They undergo polymerization to create an irreversible bond to convert from oil to a cross-linked solid that stops the water molecules from penetrating the wood grain.

Early Chinese shipbuilders used tung oil to waterproof the boats. Woodenware uses tung oil to waterproof them so that soups and liquids do not leak to the outside. The oil fills any pores and scratches in the wood grain, discouraging any liquid from seeping into the innermost part of the timber.

It is Food Safe

If you happen to inhale or ingest tung oil while working on a project, you should not feel worried. It is safe to drink, taste or smell it. Woodenware with tung oil is safe if you place food on it. Wooden toys are safe for your kids too.

When using tung oil in making cutting boards, woodenware, toys, countertops, and baskets, you have to cure them for thirty days. If you use it without complete curing, the tung oil disappears and does not serve its purpose. Bacteria and molds cannot penetrate these kitchen utensils’ surfaces with a tung oil finish.

No Prepping

Applying tung oil on the wood does not require preparation like sanding. Since tung oil does not need a smooth or glossy finish, you can use it directly without preparation.

What you need is a semi-gloss or semi-smooth finish. The secret is to apply a thin layer of tung oil on the surface to achieve the desired finish. Too much oil leaves a blotchy surface.

Tung oil does not require evaporation as a method of curing. It dries naturally on oxygen, heat, or U.V. light. Experts recommend using a clean cloth or paintbrush for six coatings of tung oil on the wood.

Allow the wood to dry after each coating for over six hours. Slowly run your finger on the surface of the wood to test if it has thoroughly dried before applying the next coat. Repeat the process until you finish six coats.

It’s Repairable

Tung oil cures by rubbing some oil on the affected surface. Apply it on the affected area without over-saturating with excess tung oil. Cut small squares from old cotton cloth and dip them in the oil. Scratches and bruises in tung oil finishes are repairable.

Cons

It takes Times to Cure

After applying a coat of tung oil, monitor the woodwork by checking on its surface. The curing period for tung oil is about thirty days before you can use the furniture or project. This factor has discouraged some woodworkers from using this oil, especially if they are in a rush.

Wipe off excess oil that overflows the wood surface. Keep the wood free from heavy objects, dirt, dust, pet hair, falling leaves, and mud. Removing them when they get stuck in the wood would be difficult.

Disagreeable Odor

Drying oils have a distinct odor that some may find offensive. In the case of tung oil, it emits a mildly unpleasant odor that could last for several days to weeks. As the days pass by, the smell becomes less intense.

Although harmless, you must wear a face mask to avoid respiratory problems. Applying a polyurethane, shellac, or varnish coat on the tung oil can minimize the bad smell. Diluting the oil with mineral spirit is another method of removing the unpleasant odor.

Challenging to Store

It is challenging to store leftover pure tung oil. Once you have opened the container, the oil surface forms a film or gummy deposits on the rim and edges of the container. You must store the tung oil away from direct heat to prevent this problem. Keep it sealed at a cool temperature.

Costly

Pure tung oil is expensive due to its rarity. Even dark tung oil is costly. The best way to get a bargain is to buy it in bulk if you are working on large projects. The price of tung oil is almost 25 percent higher than finishing oils, such as linseed oil, shellac, varnish, lacquer, or paint.

Slow Penetration

Tung oil has a slow penetration into the wood grain. It requires six coats of oil to penetrate the wood. It takes patience and time to complete the coatings. The key to a perfect penetration is to sand before applying another coat, making sure that the oil has dried or it will smear.

It takes 3-4 days before the coat dries up, and complete curing will take 30 days. A piece of woodwork or furniture using tung oil will take more than a month to complete.

Tips for a Quick Cure

Tung oil offers a natural finish to your woodworking project, but its downside is it takes time to cure. One of the proven techniques in curing is to keep the coats thin and not overflowing with excess oil. Tung oil may not be a suitable wood finish if you work on an extensive woodworking or furniture project.

Use a clean cotton rag or paintbrush and slowly coat the wood. It cures fast given the right conditions, such as direct sunlight at 50 to 75 degrees. Place the woodwork outside on a sunny day for at least 5-6 hours.

Conclusion

Tung oil is an old method of waterproofing ships and protecting the wood grain. It gives off a rustic and bright finish unmatched by drying oil products in the market. Using tung oil is one way of saving mother Earth because it is sustainable, organic, food safe, and eco-friendly. Since its price is a bit costly, the only way to save money is to buy it in bulk, especially when working on large projects. Store leftover oil in a cool, dry place.

What is Tung Oil? (Uses and Applications) (2024)

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