Tung oil has a luster and honey-tone finish; the finish protects the wood and makes it look better. But, how many coats of it do you need?
You need 4-6 coats of boiled tung oil for proper coverage and durability. For raw tung oil, you need only 2 coats for proper coverage; that’s because raw tung oil is thicker.
However, you must thin tung oil with turpentine or mineral spirits before applying it.
Why Does it Matter?
The number of coats of tung oil determines the dry time of the finish, how deep the honey-tine finish will be, and the water resistance, durability, and strength of the finish.
Tung oil is an oil-based wood finish that is gotten from the Chinese Tung tree. Like all oil-based finishes, the number of coats determine its quality of the finish.
The more coats you apply, the longer tung oil takes to dry. The longer it take it to dry, the longer it takes to complete the painting project. That’s because you must wait until one coat dries before you apply the next one.
Besides the dry time, the number of coats also determines the tone of the finish. Tung oil has a honey-tone finish on wood when dry. The more coats you apply, the darker the honey-tone finish gets. If you apply fewer coats, the honey-tone finish will become light and transparent.
The water-resistance levels and durability of the finish also depend on the number of coats you apply. If you apply more or less than the needed number of coats, the finish will not be as protective or water-resistant as it should be.
Apply Two Coats if:
If the finish looks lighter than you want, you need another coat to deepen it. The more coats you apply, the deeper or darker the finish will be.
Also, if you can feel the texture of wood after applying tung oil, you need another coat. This because it means that the finish is too light and can get damaged easily.
Tung oil penetrates the wood as it dries; if you can see and feel the wood texture after applying it, it means the wood has absorbed the finish, and you need another coat. If the wood absorbs the finish, the finish won’t protect the wood from damage. The finish must form a layer over wood to protect it.
You can also use the water test to know if you need an extra coat or not. To do this, pour water over the existing finish, and wait a few minutes. If the water absorbs into the finish, it means the finish isn’t strong enough and doesn’t provide enough coverage to prevent pores from absorbing water, so you must apply another coat.
If the wood doesn’t absorb the water, you don’t have to apply another coat. But, this test should be done after the tung oil has dried. You can also check the user’s guide or manufacturer’s instructions to know the exact number of coats you need.
If You Don’t Use Enough Coats:
If you don’t apply enough coats of Tung oil, the finish won’t be strong enough to protect the wood from water, moisture, rotting, or water stains. The finish will become light and transparent too. Additionally, the finish might appear streaky because it may not soak into the entire wood.
Not applying enough coats also means the finish will have poor wood protection. Over time, the finish will become riddled with lines and cracks, indicating that the Tung oil is becoming weak.
Tung oil is used to waterproof wood and give it a honey-like finish. To achieve a deep honey-like finish, you must apply at least 4 coats of it. To make wood waterproof, you must apply 4-6 coats of tung oil.
So, if you don’t use enough coats, the finish will not cover the entire wood surface, meaning the wood will be exposed to water.
If You Apply Too Many Coats:
If you use too many coats of Tung oil, the finish won’t dry in time and will turn tacky. That’s because there will be too much of it on the wood, and wood can’t absorb all of it.
The remaining Tung oil that isn’t absorbed by wood will remain on top of the surface where it won’t dry and will turn sticky. After a while, this will cause a messy finish on the wood.
Also, overapplying Tung oil will cause the finish to dry soft. After it is applied, the wood oil dries and reacts with dry air to become hard and strong. However, if you apply too many coats, the wood oil won’t be exposed to air because there will be too much of it on the wood. Instead, only the top layer of the will be exposed to air, while the remaining layers underneath will remain damp.
Since the basecoats are damp, the hard top layer will feel soft when pressed or made to support furniture weight. Eventually, the finish will begin to crack and give way.
Tung Oil Dry Time Between Coats
It takes pure Tung oil 24-72 hours to dry enough for a re-coat. That’s because it doesn’t have dryer additives or metalized drying agents to make it dry faster, so the finish takes longer to dry.
On the other hand, boiled or refined Tung oil takes between 4-6 hours to dry enough for a recoat. That’s because it is formulated with drying additives that make the finish dry faster.
After applying the first coat of Tung oil, you must wait 60-90 minutes to allow it to be absorbed in the wood. After the first coat soaks into the wood, wait another 60-90 minutes for the finish to dry enough to be sanded with 400-grit sandpaper. Only after the existing coat penetrates the wood and becomes hard, you can recoat it.
If you recoat it too soon, you’ll trap moisture between coats, and this can cause the Tung oil to turn sticky. Recoating it too soon can also blur the finish making it look amateurish.
Number of Coats For Different Surfaces
You must apply at least 4 coats of boiled tung oil to the wood. For raw tung oil, you need to apply 2 coats only. That’s because Raw Tung oil is thicker, so it has a better coverage.
However, if you apply it over porous woods such as Oak and maple, you need more coats. That’s because these porous surfaces have large pores that allow easy penetration. So, to cover these surfaces, you need more coats. Or, you need to apply stain-blocking primer or wood cindtioner before applying the wood oil.
For tables and tabletops, you must apply 3 coats of Tung oil. Tables don’t experience heavy usage or frequent exposure to moisture, so you don’t need too much protection.
Start applying 2 coats of Tung oil on pine wood and add more coats if you aren’t satisfied with the finish. This is because pine is a type of softwood, and softwoods don’t absorb wood oils evenly.
So, starting with a few coats and working your way up as long as the wood is still absorbent is advised. However, you must use a wood conditioner to prep the pine for Tung oil absorption.
You must apply 2-3 coats of tung oil to the guitar necks. You don’t need too many coats of it on a guitar neck since the surface won’t be exposed to moisture, UV rays, or other factors that can damage it.
You need 4-5 coats of Tung oil for a butcher’s block. But, you must apply it underneath the butcher’s block. This is to prevent water and stains from the top from seeping below the wood and causing mold.
For floors, you need 4-6 coats of Tung oil because floors are high-traffic areas in the home. Floors experience a lot of use and weight; as such, you need a lot of coats to provide durability and protection to the floors from factors that damage them.
In summary, Tung oil requires an average of 4 coats for good coverage, moisture resistance, and durability. But, the number of coats also depends on the surface you are applying it to. High-traffic surfaces need more Tung oil, while low-traffic areas need less.
Tony is a professional painter and an author of DIY Geeks. Tony has completed over 1,000 painting projects for his clients. It's safe to say he knows what he Is talking about,