Applying Tung oil over wood stain refers to the process of altering the color or adding more protection to an already stained surface. So, can you do it?
You can apply Tung oil over regular wood stain, but the finish must be dry and you must apply thin coats. You can’t apply Tung oil over penetrating stains such as gel or lacquer stains as they don’t allow penetration.
Note: Tung oil sticks better to oil-based wood stains as they use the same solvent (oil).
Does Tung Oil Adhere Over Wood Stain?
Tung oil does adhere over regular (water or oil-based) wood stain. But, sanding the wood stain with fine-grit sandpaper before applying it is necessary.
Tung oil doesn’t adhere to topical or sealed wood stains as their topcoat will prevent it from penetrating the surface. Since Tung oil needs to penetrate a surface to stick but it can’t penetrate a sealer topcoat, the wood oil won’t stick unless you remove the sealer.
You must apply thin coats of Tung oil over the wood stain for it to stick. If you apply thick coats, the wood oil won’t stick as it won’t be able to soak into the wood pores (which are already filled with wood stains).
To improve the adhesion of Tung oil and wood stain, sand the surface with fine-grit sandpaper. Sanding will create tiny pores (holes) that the wood oil will penetrate into, and remove parts of the finish making penetrating easier.
How To Apply Tung Oil Over Stain?
To apply Tung oil over stain do the following.
- Clean and Degrease the Finish.
- Sand the Finish.
- Apply the Tung Oil.
- Wipe the Excess.
The tools you need for this project are listed down below.
- Fine-grit sandpaper
- A degreaser
- An angled paintbrush
- Clean lint-free rags
- Tung oil
1. Clean and Degrease the Finish
First, clean and remove grease from the stain coating. Grease will prevent Tung oil from sticking properly and can taint the finish.
To clean it:
- Wipe the surface with a degreaser.
- Use a rag to remove dust and clean the wood.
- If the finish is sealed, use a paint stripper to remove it.
2. Sand the Finish
Once the wood stain coating is dust-free, sand it with fine-grit sandpaper. Sanding will remove imperfections from the surface, create tiny ridges and allow the wood oil to penetrate the coating.
Sand the wood with fine-grit sandpaper and not coarse-grit sandpaper. Coarse-grit sandpaper will remove the wood stain coating and scratch the wood. After sanding, remove dust and debris from the surface with a clean rag.
You can also wet-sand it, but you must wait a few hours for the surface to dry. So, dry-sanding is a faster alternative.
3. Apply the Tung Oil
Once the wood stain coating is clean and sanded, apply the Tung oil:
- Pour Tung oil into a clean bowl.
- Dip a clean lint-free rag into the bowl.
- Use the dampened rag to apply the Tung oil.
- Rub the wood oil over the surface by moving the rag in a circular motion.
- Apply 3 coats of Tung oil over the stain coating.
- Wait until one coat dries before applying the next one.
- Use an angled paintbrush to cover tight spots and corners of the wood.
4. Wipe the Excess
You must wipe the excess from the wood surface. If you don’t wipe it, the finish will turn sticky (or tacky). After you remove the excess oil, allow the Tung oil to dry for 3 days before using the surface. Optionally, you can seal it with a sealant after it dries.
Does Tung Oil Darken Wood Stain?
Tung oil doesn’t darken wood stain, it only makes its color appear deeper. Since the Tung oil finish is thick and reflects low light, the color of the wood stain will appear darker. But, if you remove the Tung oil the natural color of the wood stain returns.
The Tung oil finish will develop an amber (gold-like) color shade because of the high amount of wood oils in its formula. This happens once the wood oil cures (fully dries).
To prevent an amber (gold-like) color shade, thin the Tung oil with mineral spirits (up to 50%) before applying it. This makes its flow (coating) lighter, so it doesn’t deepen the color of the wood stain and makes it easier to apply.
Which Types of Wood Stain Can You Apply Tung Oil Over?
The types of wood stain you can apply Tung oil over are listed below.
1. Water-based & Oil-based Wood Stain
You can apply Tung oil over a water-based stain, but the coating must be fully dry. Optionally, you must sand the coating to improve the adhesion.
You can also apply it over oil-based stain because it has a high volume of tree oil, so it’s compatible with Tung oil.
However, you must sand off (remove) the glossy layer of oil-based stain to allow the Tung to penetrate. If you don’t, the glossy layer will prevent the wood oil from penetrating its coating, and the wood oil won’t stick.
Which Types of Stain You Can’t Apply Tung Oil Over?
1. Miniwax Stain
You can’t apply Tung oil over the Minwax stain. That’s because Miniwax stain is also a penetrating oil finish and will fill the wood pores. So, if you apply Tung oil over it, the wood oil won’t be able to penetrate and won’t stick.
2. Gel Stain
You can’t apply Tung oil over Gel stain. That’s because Gel stain is a penetrating finish that can’t be painted over. When dry, it forms a moisture-resistant coating that repels liquid, including wood oil.
