Teak oil gives the wood a rich appearance and offers low resistance to water and moisture. So, can you apply polyurethane over teak oil?
You can apply polyurethane over Teak oil to increase the durability of the finish. Polyurethane doesn’t need to penetrate the surface to stick, so it will stick over it. However, you must sand it before sealing it.
On the other hand, you can’t use Teak oil over polyurethane because the wood oil needs to penetrate the surface to stick, and polyurethane prevents moisture (including paint) to penetrate its coating. So you must remove the sealant first before applying the wood oil.
Polyurethane sticks over teak oil because it is a topical sealant that doesn’t need to penetrate a surface to stick.
However, you must lightly sand the finish before applying the sealant. Sanding creates tiny ridges on the finish that help the sealant stick better.
To get a better result, you must use water-based polyurethane because it doesn’t need to penetrate the surface as deep as oil-based poly to stick.
Teak Oil Dry Time
Teak oil must dry (or cure) for 12-24 hours before sealing it. This gives the wood oil coating enough time to harden and dry enough to support the sealant coating.
For Teak oil to dry and cure, the paint solvent must evaporate and the paint particles must harden. This takes between 12-24 hours. However, its dry time depends on the humid levels, the number of coats, and the thickness of the coat.
If you seal it too soon, the finish will turn sticky. That’s because if the coating is still wet (not dry) and you seal it, the evaporation process of the solvent will be stopped. This will cause wood oil to bleed through and stain the polyurethane clear coat.
Also, the coating must be rigid because you have to sand it before sealing it. If you sand a wet Teak oil coating, the sandpaper will remove the entire coating and ruin the finish.
How To Apply Polyurethane Over Teak Oil?
Before applying sealing Teak oil, you must prep its surface.
Also, you need a few tools and supplies:
- Medium and Fine-grit sandpaper
- Clean rags
- Paint thinner (optional)
1. Clean and Degrease The Finish
First, remove grease, oil, dust, and grime from the finish. If the Teak oil finish has grease or grime, the sandpaper will get clogged with filth.
To clean it:
- Use a cleaning solution or degrease such as WD-40.
- Apply the degreaser.
- Use a soft brush to wipe off the dust and grease from the finish.
- Remove degrease residue using clean water.
- Leave the finish to dry.
2. Sand The Finish
Once the finish dries, sand it using fine-grit sandpaper. Sanding will remove bumps and imperfections from the finish so the polyurethane can dry properly. After sanding, remove the dust from the surface using a clean rag or a vacuum.
If you want to remove the Teak oil, use medium-grit sandpaper or paint stripping compound.
3. Apply Primer (Optional)
If you don’t want the teak oil color shade to show on the finish, apply a primer before sealing it. Polyurethane is a clear coat, so the color shade of the finish won’t be changed. However, a primer will cover the finish color shade. This means the finish will have the same color as the primer.
Also, a primer will help the sealant stick better over the oiled surface. Latex primer works best.
This step is optional, so you can skip it.
4. Apply The Polyurethane
Once the oiled wood is clean and sanded, apply the polyurethane. If you use a sprayer, spray it over the finish evenly. For regular polyurethane, use a bristled paintbrush or a paint roller.
You must thin oil-based polyurethane with mineral spirits before applying it. This makes its coating lighter, easier to control, and helps it to dry faster.
You must apply 2-3 coats of polyurethane. Wait until the previous coat dries before applying the next one.
Mixing Teak Oil With Polyurethane
You can mix oil-based polyurethane with Teak oil because both finishes use oil as their solvent and are compatible with each other. Oil-based polyurethane is thicker than Teak oil. So, use it less in the mixture or thin it with turpentine to make its flow light and smooth.
If you mix Teak oil with water-based polyurethane, the mixture will vary in color, dry time, solvent, and consistency. That’s because water-based polyurethane uses water as its paint solvent, and water isn’t compatible with oils.
Also, they have different dry times. So, if you mix them, one part of the mixture will dry while the other will still be wet. This will cause the paint (mixture) to crack and peel off.
Teak Oil Doesn’t Stick To Polyurethane
You can’t apply Teak oil over polyurethane because it can’t stick over because it can’t penetrate the coating. Polyurethane forms a glossy moisture-resistant layer over the surface that prevents liquid to penetrate its coating.
To apply teak oil over it, you must sand the sealant off or remove it. Sanding the stress areas of sealant will create holes (spaces) for the wood oil to penetrate. However, the bonding between them won’t be good.
So, it’s best to remove the sealant completely, and then apply the wood oil.
You can apply polyurethane on teak oil because polyurethane doesn’t need to penetrate the surface to stick. This means it will stay (stick) over the finish and protect it. Polyurethane produces a glossy layer resistant to water, moisture, and scratches when dry. This layer protects the teak oil and the wood underneath.
However, you can’t apply teak oil over polyurethane. That’s because teak oil needs to penetrate the wood grain to stick, and polyurethane coating repels moisture. So, if you apply it, the wood oil won’t stick and will slide off the glossy finish of the sealant.
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,