Tung oil is a famous historic Chinese oil used for several centuries to enhance and highlight the elegance of various wood types, including the notorious walnut wood. For this post, I have tested tung oil on walnut to see how compatible they are!
What’s Tung Oil?
Tung oil (or China wood oil) is a pale-yellow, pungent drying wood oil finish extracted from tung tree seeds.
It is native to China and is mainly named for its heart-shaped leaves since ‘tung’ in Chinese refers to ‘heart.’ In the 14th century, Chinese merchants used this wood oil to waterproof their wooden ships and added an extra layer of protection.
There are mentions of tung oil in Confucius’ writings around 400 BC. This is among the reasons tung oil is widely known as China oil.
Tung oil is mainly obtained from the seeds of two tree species, Aleurites Montana and Aleurites fordii. Pure tung oil is a natural finishing oil product that can provide a flexible, tough, and highly water-resistant coating.
It is often grouped with linseed, safflower, soybean, and poppy oil. Moreover, it is famous for its golden tint.
Tung oil is considered the best penetrating dry oil in the market due to its unique characteristics, which include its ability to provide a tough protective film that can keep the wood from rotting.
Kinds of Tung Oil and Their Differences
Today’s wood oil market offers a wide selection of various tung oils that have their own characteristics and properties. The most popular kinds are:
Pure Tung Oil
Pure tung oil is easy to identify as it contains no solvents. The process for this kind is done by cold-pressing the seeds.
It is a safe, non-toxic, and eco-friendly oil that can draw the interest of homeowners and craftsmen alike.
Tung Oil Finish
Conversely, the tung oil finish is made from a combination of oil and polyurethane/urethane. It provides enhanced protection to the wood and can leave behind a polished finish on top.
This finish is for people who expect their wood furniture to be durable enough for everyday use, traffic, and wear.
Tung Oil Varnish
Lastly, the tung oil varnish is mainly formulated with varnishes and solvents. It is a rather robust solution that is an ideal option for wood surfaces that are frequently used. Tung oil varnish stands superior in terms of durability and is widely known for leaving a radiant finish.
Is it Okay to Use Tung on Walnut Wood?
Tung oil is an excellent walnut wood finish! It can give the wood surface an appealing dark brown luster that many homeowners would find attractive.
Walnut wood has a porous or open grain structure requiring several tung oil coatings to fill. Doing so will provide a smooth and even top-layer finish.
Due to the multiple pores with a higher diameter than most wood types, walnut can suck up the tung oil like a sponge to water. It often makes finishing hard since the tung oil can’t sit properly until you fill all the pores.
However, this specific trait can also be advantageous. I’ve found that the tung oil can really get in there and make walnut wood more flexible, reducing its susceptibility to cracking and splitting.
When I apply that first coat of tung oil, it’s really all about saturating those walnut wood fibers. It will also prepare it for the next coat. A protective layer will build up on the surface from the second tung oil coat onwards.
But, here’s a pro tip that has saved me both time and effort: mix tung oil with your chosen varnish before applying it to walnut wood. This blend not only offers a smoother finish but also minimizes the number of coats you’ll need to get that perfect look.
Can You Darken Wood With Tung Oil?
No. Tung oil does not darken walnut. However, you may use the darker variant (dark tung oil) to further darken the wood’s natural hue.
If used and appropriately utilized, purified tung oil may highlight and accentuate the glorious wood grain and pattern of walnut. It will also not discolor nor turn dull over time.
Additionally, tung oil does not cause any yellowing. If you properly maintain the wood and keep the finish fresh, you can enjoy the walnut’s natural color longer!
Is Tung Oil Food Safe?
Tung oil is safe to use on most walnut wood. After its extraction from pressing seeds of tung trees, the pure oil is already safe for food and skin.
Although, please take note that walnut wood itself can be toxic. While tung oil can form a protective coat on kitchen countertops and utensils since it repels moisture, contact between the food and wood is not recommended.
Walnut wood is toxic in some respects. Specific parts or aspects of walnut wood can be toxic to certain people. For instance, walnut pollen can induce allergic reactions, while walnut dust contains a toxic substance.
You must utilize the pure variant of tung oil or other food-safe finishes on walnut wood for it to be food-safe.
Shelf Life Of Tung Oil
The shelf life of tung oil depends on various factors and several components like storage, type, environment, and product quality.
So here’s the rundown based on what I’ve observed: If you store tung oil properly, keeping it away from direct sunlight and in a cool, dry place, it can last up to a solid two years. Though, that is not guaranteed. You need to observe the oil over time.
I’ve had instances where the oil began to thicken or become less user-friendly sooner than expected. When that happens, it’s a sign that its usable lifespan is shorter than what you might have anticipated.
In contrast, an unopened container of tung oil has the capacity to remain viable for extended periods, spanning several decades, as long as it is stored appropriately.
Advantages Of Using Tung Oil Finishes On Walnut
In my experience, tung oil provides many benefits when used on walnut wood. Refer here to know what exactly they are!
Natural Appearance
Tung oil can accentuate the natural elegance of walnut by further intensifying the dark brown shade — this while bringing attention to the wood’s distinctive and unique grain pattern!
The wood oil can significantly enhance the natural appearance of the walnut and further bring out its captivating appeal and beauty to the surface.
Eco-Friendly
It is a natural wood oil that is non-toxic and free from harmful chemicals. These characteristics allow you to use tung oil on indoor and outdoor walnut furniture safely! You may even use it on surfaces that can come in contact with edibles.
Protection
Applying this natural oil on a walnut wood surface creates a protective layer and barrier to shield it from dangerous environmental conditions like UV rays, moisture, and insect infestation.
Easy Application
Like most wood oils, this one is easy to apply and use. You don’t need to have any special knowledge, practice any distinct technique, or use specific equipment to apply tung oil properly.
Durable Finish
Its durability is among the most significant benefit of tung wood oil on walnut. Once it reacts with the oxygen around us, the oil will naturally harden and form a tough protective coating that will remain effective for a long time!
Disadvantages Of Using Tung Oil Finishes On Walnut
Like every other wood oil in the market, tung oil has disadvantages that can be a deal breaker for some woodworkers and homeowners.
Slow Drying Time
This oil is notoriously known for having a slow drying time. The waiting game can take days in between coats! This flaw is undoubtedly enough to make many homeowners turn the other way.
Time-Consuming
Tung oil requires several applications and coats to penetrate the wood entirely. Slow drying time can result in several woodworkers losing their patience. A single walnut wood piece will undoubtedly take weeks to dry and cure properly!
Requires Thinning
Tung oil might require you to thin it with varnish or mineral spirits. That can prolong the entire curing process even more.
Costly
Tung oil is not the cheapest natural wood oil in the market, that’s for sure. It might even cost more than most finishes. That makes it a no-go for carpenters or woodworkers that are tight on the budget.
Requires Maintenance
To maintain and sustain the wood finish, the tung oil demands frequent upkeep and maintenance — including sanding, reapplication, and curing.
(For more detailed information, check out this post about Tung oil’s advantages and disadvantages next!)
How Tung Oil Enriches The Beauty Of Walnut Wood
Tung oil can enhance and enrich the natural beauty of walnut wood furniture and pieces. It can do so in several ways.
The formula or treatment will seep through the pores and crevices of the walnut wood, settling in and effectively plugging in any openings. It will create an outer, even protective layer.
That process results in a natural, glossy, warm polished look that further enhances the wood’s appearance.
Subsequently, the natural oil can enhance what is already there — which means it can enrich the existing wood grain pattern and color of the walnut wood. It can accentuate the wood surface by deepening the dark brown luster.
At the end of its curing, you will have a full tung oil-finished wood surface that looks even more exquisite, warm, and cozy than it did!
Applying Tung On Walnut: Tools and Steps
Tung oil is valuable in varnish manufacture due to its unique properties]. It is why learning how to properly apply it is necessary if you plan on using it.
Fortunately, it is relatively easy to apply tung oil on walnut wood. You need a couple of supplies and a lot of patience to get through the entire curing period! Here is what you need to do:
Supplies
Before starting the application process, you should gather the proper supplies and tools. You will need the following:
- Tung Oil (choose the type you need or prefer)
- Scrap walnut wood to serve as a sample
- Walnut furniture or woodwork
- Mineral spirits (if you plan to thin down the oil)
- Sandpaper
- Rags
- Plastic cup
- Bristle brush or sponge brush
- Latex gloves
- Synthetic or abrasive finishing pads
Step #1: Prepare the Walnut Surface
Before you apply the oil, you must prepare the walnut wood surface first. Sand the wood surface using 120-grit sandpaper. Ensure you do so in a well-ventilated area.
The sanding process will undoubtedly create sawdust [1], irritating the skin and eyes. For certain people, it can also trigger an allergic reaction. Ensure that you wear the proper protective gear, like gloves and goggles.
Clean the wood’s surface and free it from dust, debris, and grease using a damp rag. Follow it up by applying TSP cleaner or trisodium phosphate to eliminate stubborn dirt or dust particles.
Sand the surface once again using sandpaper. Ensure that the surface is even and smooth.
Step #2: Thinning the Tung Oil Using Mineral Spirits
While not an extremely essential step, I would still recommend you thin down the oil. Doing this gives you a smoother finish and a faster drying process.
Pure tung oil usually requires a long drying time. Mixing and combining it with mineral spirits can lead to quick evaporation, resulting in faster drying.
To properly mix the two components, you must take the appropriate amount of oil and pour it into a plastic cup or glass jar. Next, pour in mineral spirit (equal the amount as the tung oil) and mix them. Do so slowly.
Step #3: Apply the First Coat
Take a tack cloth or bristle brush and lightly dip it in the mixture of mineral spirits and tung oil. Apply the initial tung oil coat over the surface steadily.
My tip is to use the mixture first on a scrap or sample walnut to observe the color transformation. That way, you know what results to expect.
Apply the tung oil, then follow the wood grain’s direction for quick and efficient absorption. Put only a thin layer to attain a smooth and even layer and finish.
Let the oil sit for 30 minutes before you wipe off any excess oil and puddle to achieve an even coat.
Step #4: Let it Dry, then Sand the Surface
Let the walnut wood dry and let it sit or set thoroughly for a day. The drying time can vary from 1-3 days, depending on the weather and humidity levels. You must wait for the coat to dry before applying the second coat.
Once the initial coat is dried, sand the surface using sandpaper (preferably 320-grit). Make sure to follow the walnut grain’s direction to avoid marking, scratching, or bubbles. You may also utilize an abrasive pad between the coating for a more consistent and glossy finish.
Step #5: Apply More Oil Layers
Apply and spread the second tung oil layer to the wood, similar to what you did to the initial coat — follow the grain and ensure no brush marks are left behind.
After half an hour, remove any droplets or excess oil to gain and achieve an appealing and smooth finish. Imitate the steps above as you apply the successive coatings.
How Many Coats Of Tung Oil You’ll Need?
Apply at least five tung oil layers or coats to attain a beautiful finish and a tough protective layer that can shield against moisture, rot, and decay. Lightly sand the surface in between coats to pull off an even top layer.
How Long Should Tung Oil Dry Between Coats?
If you are working on other wood types, you must allow the tung oil to dry for at least 8-12 hours in between coats, but with walnut, you will need at least 24 hours. This wood type has more pores than other woods, so the drying time is longer.
Step 6: Allow the Oil Finish to Dry and Cure
Apply at least five tung oil coats on the surface. Let the wood piece or furniture sit for about a day between coats.
After the last coat of tung oil, allow it to cure entirely for at least 14 days. Note that the slow drying process is a major flaw of this natural oil, so ensure you pack a lot of patience to get through this wood project.
Sometimes, it might even need 30 days to cure entirely! It would be best to avoid using the tung oiled-walnut furniture unless wholly cured and dried.
Can You Apply Tung Oil On a Walnut Butcher Block?
Yes, you may apply tung wood oil on a walnut butcher block since it is non-toxic, food safe, and can create a protective even coat that can withstand moisture and water damage.
Using tung oil on a walnut butcher block means supplying it with a good layer of water resistance. Moreover, it will also have an attractive matte finish!
Tung Oil Maintenance & Care After Application
You must practice proper maintenance and upkeep to sustain the walnut’s durability, flexibility, and luster. For that, here are a couple of tips from my book:
Dust Regularly
Periodically dust the walnut wood furniture to prevent it from accumulating on the surface. You may use a gentle and lint-free rag or cloth to avoid any damage from happening on the surface.
Avoid Moisture Exposure
One effective way of keeping your walnut furniture safe and well-maintained is by protecting it against moisture. Excessive exposure to moisture can cause decay, rotting, and marking.
Wipe off any liquid spilled on the surface and store it in a dry and cool location.
Store the Wood Item Carefully
Proper storing plays a considerable part in maintaining your walnut wood that’s treated with tung oil. Ensure you keep it in a dry area or location and avoid humid or moist places.
Reapply Tung Oil As Needed
Over time, the natural oil may become dull and parched, especially if not properly maintained. Apply a thin coat of tung oil to keep the glossy appearance. Make sure you sand in between coats.
It is necessary to reapply tung oil on walnut wood frequently. The frequency will depend mainly on the usage and intensity of sun and moisture exposure.
Typically, an annual application is required. If you notice the wood to have evidence of listlessness, crevicing, or aridity, it is a sign that reapplication is needed.
Avoid Harsh Chemicals
Keep harsh and robust chemicals away from the wood. Avoid using ammonia or bleach to clean it off. Doing so can lead to unwanted stains and marks.
What’s the Best Finish to Use On Walnut Wood?
There are a couple of wood finishes that are ideal to use on walnut wood. The best kinds are oils that can emphasize its darker color and make its natural beauty more appealing to the eyes.
Among the best choice for a walnut finish are:
- Tung oil
- Varnish
- Boiled Linseed Oil
Tung Oil Vs Linseed Oil
To compare tung oil with linseed oil, it is imperative that you take their specific purpose and job into consideration since both oils have their unique advantages and drawbacks.
Linseed oil is deemed the go-to wood finish. It is a natural oil that can produce a softer and less resilient finish than others. Despite that, it is best suited for wooden pieces that experience routine exposure to water and moisture.
Meanwhile, tung oil provides a strong, long-lasting coating that accentuates a wood’s natural beauty. It is truly an ideal choice for woods like walnut.
FAQ
How long should you let tung oil sit until it’s fully cured?
In applying this oil, the curing process interval should span 30 days. That and a recommended 7-10 days’ worth of waiting to ensure you gain the ideal results.
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Conclusion
Using tung oil on walnut will offer you many benefits for your wooden project. With correct application, proper curing, and regular maintenance, the tung oil would offer a robust, durable, and gorgeous finish that any homeowner would love!
You've probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.
Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.
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