What is Tung Oil: Everything You Need to Know
When I was working to finish my wood desk, I wasn’t sure what finish to go with. I saw a lot of people mention tung oil. I wanted to learn more about and see if it would fit my needs. Here’s what I’ve found.
Tung oil is a wood finish that comes from tung trees. It is completely food safe and chemical free. It can be applied on wood projects by wiping it on directly.
From what I know, tung oil is a finish that can take your wood project to another level. It looks amazing when it’s applied and really brings out the character in the wood.
Tung oil can be applied to most wood projects but make sure to read up on how the oil can change the color of the wood.
There are also a few things you need to know, like application process and dry time. I will go into those topics in this article.
What is tung oil and what does it do
|Ingredients||Extracted seeds from tung tree|
|Dry time||12-24 hours|
|How to apply||Brush or wipe on|
|Average cost (16 fl oz)||$15|
|Types||Pure tung oil, tung oil/varnish mix|
Let’s first start with why someone might use tung oil. When you work on a wood project, the last thing you need to do is finish the wood. Finishing wood basically means to apply a coat of oil, like tung oil, or a varnish to seal and protect the wood. Otherwise humidity can cause the wood to dry and crack. You don’t want that!
That is why we turn to solutions like tung oil. Tung oil is a popular wood finish that is applied on many wood projects. Researchers and historians believe that tung oil has been around for nearly 2000 years. Wood enthusiasts love tung oil because of the rich character it adds to wood projects. It brings out the grains and fibers in the wood giving it an earthly look.
Where does Tung oil come from? It comes from nut like seeds that are found on trees called the Vernicia fordii. These trees are mainly found in places in Asian like China and Burma. It is why many people might refer to tung oil as the China wood oil. To extract the oil from these seeds, the nuts are “pressed from the nut-like seeds of the tung tree” (Progress in Organic Coatings).
There are many ways to apply and use tung oil for wood projects. We will look at it in the next few sections.
How long does it take to dry
Pure tung oil takes a while to dry and harden. For any project that I am using pure tung oil I would let it dry for at least 12 hours before applying another coat. Sometimes it can take almost a full day to dry.
There are a lot of factors that go into how long tung oil can dry. These factors include:
- Amount of oil
- Humidity and temperature
- Wood type
If you are using a tung oil/varnish mix, dry time can vary. If you want to learn more about different types of tung oil mixes, read the “types of tung oil” section below.
Most tung oil mixes will have instructions on them so please read those instructions carefully. If you want a faster dry time I would recommend going with a mix or making a mix yourself. You can do this by combining tung oil with mineral spirits creating a 1:1 mix.
What does Tung oil look
Tung oil has a warm, orange color to it. When applied to it wood it can darken the wood but also bring out a lot of the grains inside the wood. One thing to note about tung oil is that it darkens over time to a warmer color.
The best way to describe how tung oil looks like when its applied to the wood is that it takes on a honey like color. It is similar to a honey stain that might be applied to woods.
There are variations to tung oil as well. For example, a company called “Real Milk Paint” sells a dark tung oil. They describe it as pure tung oil with “naturally occurring resinous hydrocarbon for color”. This dark tung oil will offer a darker color.
You might find variations in tung oil color if it comes in a varnish mix. While these are not pure tung oil, they show how tung oil can be mixed with other ingredients to produce a different color.
There are several methods to applying tung oil. You can apply it straight to the wood, which can work but you might have difficult getting the oil to penetrate into the wood. You can also mix it with a solution like mineral spirits or a citrus solvent.
Before you start applying tung oil to your wood, you need to sand it down to at least 220 grit. I will use something like a sanding block or an orbital sander to get it to that level. Sanding the wood will allow the oil to penetrate nicely, giving it a clean and consistent application. After you do that you are ready to move on to the application phase.
Basic application for tung oil
1. Soak your cloth/brush in tung oil and liberally wipe down the surface of the wood. You want to make sure it is wet so that you can get a generous application of the oil. If the brush starts to dry, add more oil to it.
2. Let the oil soak into the wood and look for dry spots. If I see any dry spots, I will apply more of the tung oil. You want to this until the wood doesn’t soak in any more oil.
3. Wipe off the oil with a rag or an old t-shirt, once you notice that everything has soaked in. When you do this make sure there are no more wet spots left. The surface will still be wet to touch but that is perfectly normal.
It is now ready to cure and harden. This process can take a while. I’ve seen tung oil take a few days to harden. You really want to be patient with this process.
Other application methods explained
A popular application method with tung oil is mixing it with some type of solution.
One solution is to mix it with mineral spirits. You are basically diluting the tung oil and make the application a little bit easier. But due note that doing this will require a few more applications than 100% tung oil to get the color that you want.
Another method of applying tung oil is to use a citrus solvent. This method has been covered by tung oil enthusiasts before so I’m not breaking ground here. But basically you are mixing tung oil with a citrus solvent to create a 50/50 solution.
Anytime I mix solutions, I like to use a scale to get a precise measurement. You don’t have do this and you can eyeball it but it can help to lessen some of the guess work.
Tung oil is food safe
Tung oil is food safe and can be applied to kitchen countertops and cutting boards. It doesn’t contain any additives or chemical ingredients that you might find in other varnishes or finishes. It is derived mostly from nuts.
I’ve seen a lot of projects where people have used tung oil for their kitchens and it looks fantastic. The only concern with tung oil is that it is not completely waterproof. You might want to apply a layer of some type of varnish or polyurethane.
Applying tung oil to countertops is the same process as applying it to any other piece of wood. Just follow the steps listed above. It is recommended that you not use the kitchen during and after the application process as you might notice a strong smell.
Types of tung oil
Companies and manufactured know tung oil is a sought after product. Many companies will market their finish as Tung Oil but they may only contain a percentage of tung oil.
Here are a few example of 100% pure tung oil (amazon links)
I know these are pure tung oil because I have used them. But also note the label on the bottle. It says 100% pure tung oil. Companies can lie but I have found that products that are labeled as 100% pure tung oil are the actual stuff.
Now here is an example of Tung Oil that’s not really Tung Oil but just a mixture: Minwax Tung Oil (amazon link). Notice what the bottle says: “tung oil finish”. This wording might look enticing for someone at the store who is looking for tung oil. “Wow tung oil”. But it’s not pure tung oil and if it was Minwax would’ve stated it on the bottle.
So why do companies not sell the real stuff? There are a reasons
- Dry time
- Application difficult
Cost of tung oil can be more than using only partially tung oil. That makes sense because if you are using something like mineral spirits (relatively cheap) to dilute the tung oil.
Dry time is another consideration. Because many people are not wood working experts they don’t know everything to know about wood finishes. So they might apply the tung oil but not realize that it will takes for it to fully dry. It’s not worth it for people who just want to apply something and make it look nice.
Application difficult is also a consideration here. I don’t think tung oil is that difficult to apply. But when you consider the drying time requrie, it can be easy to mess for some people, especially beginners.
Some companies will mix tung oil with other liquids such as mineral spirits or varnish. Watco danish oil, for example, will consist of 1/3 tung oil or linseed oil, 1/3 mineral spirits and 1/3 varnish.
In order to buy the real stuff look for labels that say “100% tung oil”. If possible, look at the bottle or can to see if they have a list of ingredients.
Here are other signs that something might not actually be 100% tung oil
- Faster drying time: tung oil will never dry in less than an hour. It takes several hours and even up to a day to harden and dry
How long tung oil also depends on how much you applied. Thin coats of tung oil will dry faster than thicker coats.
Advantages and disadvantages of tung oil
There are some pros and cons you might need to weigh with tung oil. Here they are.
- Tung oil improves the quality of wood. It brings out the grains of the wood, providing a nice color and finish.
- It is food safe and non toxic. No bad chemicals to inhale or no need to worry about food safety.
- It takes a while for tung oil to dry. It can take up to 12 hours and even longer to get a full dry time.
- It might need to be mixed with a mineral spirits to get better penetration in the wood
- It can go bad or stale after some time. It doesn’t have the best shelf life so you probably don’t want to reuse it if it has been sitting at your house for a while.
Personally, I would use tung oil but dilute with something like mineral spirits. I’ve discussed this above but doing a 1:1 mix really can make the application process easier as well as reduce the dry time.
You can also buy pre made mixes, which is probably a good option for many people.