Before Tung oil forms a hard and moisture-resistant layer, the finish must dry. So, how long does tung oil take to dry?
The first coat of Tung oil dries within 24 hours, but it takes up to 3 days for all coats to dry. It takes even longer for it to cure (fully dry) since it cures through oxidization and polymerization.
However, its dry time also depends on the number of coats, humidity, and ambient temperature. There are a few methods you can use to make this wood oil dry faster.
Dry Time Between Coats
It takes Tung oil 24 hours to dry between coats. This gives the coating enough time to dry and harden so it can support another coating.
Pure Tung oil takes longer to dry than refined Tung oil. On average, pure Tung oil must dry for 48 hours before a recoat. Its drying time is higher because it has a thicker flow and doesn’t have solvents or additives that make the oil dry faster.
On the other hand, refined tung oil takes 24 hours to dry because it has drying additives and solvents that make it dry faster.
If you recoat it too soon, the finish will turn tacky and take several days to dry. If the tung oil turns sticky, you must wipe the excess wood oil off the surface and allow the remaining to dry.
Factors That Influence The Drying Time:
Ambient temperature is the biggest factor that determines the drying time between coats. The ideal temperature to apply it is 60-80 degrees (F). If the temperature is lower than that, it will take longer for the finish to dry.
Here are other factors that determine the drying time:
You must apply tung oil when the humidity is lower than 50%. If there’s high moisture content in the atmosphere, the room will feel moist and wet, affecting the drying time.
If the humidity levels are higher than 70%, it will take the finish twice as much time to dry (from 24 to 48 hours). Humidity tends to be higher during cold winter months, so the finish will take longer to dry during winter. To reduce room humidity, use a dehumidifier.
2. Flow Thickness
The thicker the Tung oil coating, the longer it takes to dry. That’s because more oil will be on each coat, and the evaporation rate will be slower.
If the coating is thin, it will dry and cure faster. So, it’s recommended to thin it before applying it. To thin tung oil, use mineral spirits.
4. The Number of Coats
You need 4-6 coats of Tung oil for proper coverage. The more coats you apply, the longer it takes it to dry.
5. Air Circulation
Tung oil dries through evaporation; the faster the oils from the coating evaporate, the faster the finish dries. If the air circulates faster around the coating, the evaporation process is completed faster, and the wood oil dries faster.
Tung Oil Cure Time
It takes tung oil 3 days to cure. The curing time refers to how long it takes the wood oil to fully harden and become moisture-resistant. Tung oil cures through oxidization and polymerization, so the cure time is influenced by dry air.
Oxidization happens after the solvent (oil) has evaporated. After the solvent evaporates, air (or oxygen) gets into the coating and hardens the finish; this process is called oxidization. The dry air causes the oils and molecules to combine (harden); this process is called polymerization.
The compactness of the particles is what makes the finish moisture-resistant. So, once the finish cures, you can clean, use, and paint over it.
How to Make Tung Oil Dry Faster?
Method 1: Thin It
Thin coats of Tung oil dry faster than thick coats. So, thinning the wood oil before applying it means that the finish will dry and cure faster. That’s because the coating of the thinned wood oil will have fewer oils, so they evaporate faster.
To thin tung oil:
- Get a clean plastic bucket.
- Add the required Tung oil into the bucket.
- Add mineral spirits. To thin it, use a ratio of 2:1 (2 parts tung oil and 1 part mineral spirits).
- Stir the mixture with a paint mixer for a few minutes.
- Apply the thinned coating.
Method 2: Improve Air Circulation
The more air circulates around the coating, the faster the solvent evaporates and the finish oxidizes. So, increasing the air circulation around the coating means the finish will dry and cure faster.
You can increase the air circulation by:
- Opening all windows and doors.
- Open the air vents.
- Turning on the fans.
- Applying the Tung oil outside.
- Setting the air conditioner on ‘blow’ or ‘fan’ mode.
Method 3: Use A Hairdryer
The more heat there’s around the coating, the faster the solvent (oil) evaporates. To increase the temperature around the finish, use a hairdryer. A hairdryer will increase the temperature and dry the wood oil faster.
Here’s how to do it:
- Turn on the hairdryer.
- Set to medium heat.
- Move the hairdryer over the coating for a few minutes.
- Increase the heat of the hairdryer.
- Move the hairdryer over the Tung oil for 60 seconds.
- Turn off the hairdryer and let the finish dry completely.
It’s not advised to dry the coating completely using a hairdryer. While it’s tempting to do this, drying it completely will cause the finish to crack and peel off. That’s because it will dry too fast and the paint particles won’t harden naturally.
Method 4: Use A Dehumidifier
If you apply it during winter, you must use a dehumidifier. This is because, during winter months, the room humidity is higher than 50%. The higher the humidity, the more it takes the wood oil to dry.
Since a dehumidifier decreases the humidity levels, the coating will dry faster. All you have to do is to turn on the dehumidifier before applying it and keep it running until the wood oil dries.
Here are a few other tips to speed up the drying it:
- Apply the wood oil early in the day to take advantage of the sunlight.
- Apply it outdoors where there is better airflow.
- Apply light coats.
Tung Oil is Dry Enough If:
The following signs will indicate when coating is dry enough:
- When You Can Sand It– If the Tung oil isn’t dry, you can’t sand it. That’s because the sandpaper will get clogged with oils. But, when the wood oil is dry, the sandpaper will move freely over the coating without getting clogged.
- When Finish Becomes Moisture-resistant – When the Tung oil is dry, the finish will become water-resistant. So, pour a few drops of water over the finish. If the water penetrates the finish, the coating isn’t dry yet. If the water doesn’t penetrate the finish, the coating is dry enough.
- If The Wood oil Gets Glossy – If the finish isn’t dry, it will appear wet but when it’s dry, it will be glossy.
Tung oil takes up to 48 hours to dry and 3 days to cure. However, its drying time depends on the Tung oil type (pure or refined), coat thickness, number of coats, humidity levels, and ambient temperature.
You can speed up its drying time by increasing the heat and air circulation over the coating or by decreasing the humidity levels using a dehumidifier.