Can You Put Polyurethane Over Teak Oil? (How-To)

Teak oil is commonly used as a finishing layer to protect wood, drywall, and stains from scratches and moisture. But can you put polyurethane over teak oil?

You can put polyurethane over teak oil because polyurethane is a topical finish that doesn’t penetrate as much as wood oils. Since the polyurethane doesn’t penetrate, it will stick to the water-resistant Teak oil layer. You however have to sand before applying the polyurethane.

Teak oil on the other hand can’t be used over polyurethane because Teak oil is a penetrating wood oil. This means that Teak oil needs to penetrate to stick and since polyurethane is a hard finish, the Teak oil wouldn’t be able to penetrate the polyurethane layer leading to poor adhesion. The only way to apply Teak oil over polyurethane is to remove the polyurethane first.

Let’s dig in to discover more about applying polyurethane over teak oil.

Does Polyurethane Stick To Teak Oil?

Polyurethane sticks to Teak oil because polyurethane is a topical sealant that doesn’t need to penetrate the Teak oil. So, in a way, the Teak oil layer provides the needed requirements for the polyurethane to stick.

When it comes to painting over Teak oil, the problem many people encounter is that the paint doesn’t stick to the Teak oil. This is because Teak oil dries to form a hard and moisture-resistant layer. Since the Teak oil finish is moisture-resistant, it will repel most types of paints.

Paints are generally designed to penetrate to stick well and the Teak oil being water-resistant doesn’t allow any penetration. So automatically, paints don’t stick well to Teak oil.

However, topical sealants like polyurethane don’t need to penetrate the material as much as other paints to stick well to the surface. When you apply polyurethane, the clear coat adheres to the top layer of the surface. This is what makes it a topical sealant. Since polyurethane doesn’t penetrate deeply, it will stick to the Teak oil layer which is water-resistant.

However, you should know that polyurethane only sticks better to well-sanded Teak oil. When you sand, the sandpaper creates ridges in the Teak oil for the polyurethane to bite into. You should also know that water-based polyurethane sticks better to Teak oil than oil-based polyurethane. This is because oil-based polyurethane tends to penetrate deeper than water-based polyurethane.

How Long Does Teak Oil Have To Dry Before Polyurethane?

How Long Does Teak Oil Have To Dry Before Polyurethane?

You should leave the Teak oil to dry between 12 hours and 24 hours before applying polyurethane over it. This is because the Teak oil must have hardened before polyurethane can sit on it. And, it takes at least 12 hours for Teak oil to cure enough for polyurethane application.

Since you have to sand the Teak oil before applying polyurethane, it’s important to let the Teak oil dry enough or you’ll ruin the finish.

Teak oil is a thin wood oil that doesn’t take too long to dry. On average, Teak oil dries in less than 6 hours and cures in about 12 hours. But, it’s advised to let the Teak oil dry for about 24 hours before applying polyurethane.

One reason for this is that the Teak oil will be sanded before polyurethane application. So, the Teak oil needs to be dry and strong enough to withstand sanding without coming off.

Another reason is that the polyurethane will seal the Teak oil when it is applied to make it very difficult for the Teak oil to evaporate. So, if the Teak oil is still wet and you put polyurethane on it, the Teak oil will cause bleed-through and staining in the polyurethane clear coat.

This will ruin the finish so always let Teak oil cure long enough before sanding and applying polyurethane. Now, let’s check out how to apply polyurethane over Teak oil.

How To Apply Polyurethane Over Teak Oil?

Applying polyurethane over Teak oil will require hard work from you but here are the needed tools and supplies to make your task easier:

  • Medium and Fine-grit sandpaper
  • Degreaser
  • Paintbrush
  • Polyurethane clear coat
  • Clean rags
  • Polyurethane primer paint
  • Paint thinner (optional)

Here is a 4-step guide to put polyurethane over Teak oil easily:

  1. Clean and degrease the Teak oil
  2. Sand the Teak oil
  3. Apply polyurethane paint primer
  4. Apply the polyurethane

Now, let’s get to work.

1. Clean and Degrease The Teak Oil

Clean and Degrease The Teak Oil

The first step is to remove grease, oils, and grime from the Teak oil. If there is grease or grime on the Teak oil, the sandpaper will get quickly clogged with filth.

To degrease the Teak oil, you should use a cleaning solution or a degreaser like WD-40. These solvents will dissolve oils on the Teak oil making it easier to wipe off the grease. After cleaning the Teak oil, leave it to dry.

2. Sand The Teak Oil

Sand The Teak Oil

You should sand the Teak oil when it is dry. This helps to remove bumps and pimples in the Teak oil finish so the polyurethane can dry smoothly.

Sanding also helps to create tiny ridges in the Teak oil for the polyurethane to bite into and stick properly. You should sand the Teak oil with a fine-grit sandpaper. Medium-grit sandpaper should only be used when you want to remove the Teak oil.

After sanding, you need to remove dust from the surface so the dust nibs don’t cause pimples and bumps in the finish. You can wipe off the dust with a rag or vacuum the dust with a portable vacuum.

3. Apply Polyurethane Paint Primer

Apply Polyurethane Paint Primer

With the Teak oil well sanded and clean, you can apply a thin coat of polyurethane paint primer on the Teak oil. Though polyurethane can be applied directly to sanded Teak oil, the finish will stick better and dry smoother on a primer coating. Water-based polyurethane paint primer works best on sanded teak oil.

4. Apply The Polyurethane

Apply The Polyurethane

When the primer coating is dry, you can apply the polyurethane. If you have spray-on polyurethane, then you can easily spray enough coats of polyurethane over the primer coating. If you are using regular polyurethane, you can apply it with a bristled paintbrush.

It’s better to thin oil-based polyurethane with mineral spirits before putting it over Teak oil. This is to make the paint lighter and easier to control. For multiple coats of polyurethane, ensure to leave enough dry-time between coats.

Can You Mix Teak Oil With Polyurethane?

You can mix Teak oil with polyurethane but Teak oil can only be mixed with oil-based polyurethane. This is because Teak oil has a large deposit of natural oils that are only compatible with oil-based paints like oil-based polyurethane.

If you mix Teak oil with water-based polyurethane, the mixture will have variance in color, dry-time, solvent, and even consistency. This is because water-based polyurethane contains water and as such isn’t compatible with the oils in the Teak finish.

Oil-based polyurethane is usually thicker than Teak oil. So, if you are mixing both paints, it might be a good idea to include paint thinner like turpentine to make the mixture light and smooth.

Does Teak Oil Stick To Polyurethane?

Teak oil doesn’t stick to polyurethane. This is because polyurethane doesn’t provide the needed requirements for Teak oil to stick. For Teak oil to stick, the wood oil needs to penetrate the wood grain.

But if there is a polyurethane layer on the surface, the Teak oil will not penetrate because polyurethane is water-resistant and it doesn’t allow penetration. Since the Teak oil can’t penetrate, it can’t stick and if it cant stick, the Teak oil will slowly become a gooey mess.

So does this mean that you can’t apply Teak oil over polyurethane? Let’s find out.

Can You Apply Teak Oil Over Polyurethane?

You can apply Teak oil over polyurethane but you’ll need to either remove the top polyurethane layer or sand the stress areas of the polyurethane.

Both of these methods will abrade the polyurethane and remove the moisture-resistant polyurethane layer. This way, it becomes easier for the Teak wood oil to penetrate the polyurethane coating since it’s not as moisture-resistant as it used to be. The deeper the Teak oil can penetrate, the stronger it will stick to the polyurethane-finished surface.

The best way to paint Teak oil over polyurethane is to remove the polyurethane first. You can do this with a paint scraper, paint thinner, or a paint stripper. When you remove the polyurethane, you remove the top moisture-resistant layer completely. So the Teak oil penetrates fully.

The advantage of removing the polyurethane completely is that it gives better adhesion. The disadvantage is that it can take a while to fully remove the polyurethane coating.

You can also apply Teak oil over polyurethane by sanding the stress areas on the polyurethane-painted item. For instance, if the polyurethane is on a chair, the stress areas will be the arms of the chair and other parts that will experience high friction and touching.

These are the spots where the Teak oil will start to come off first if it doesn’t stick well. So if you sand these spots and remove the polyurethane on the chair’s arms, the Teak oil will penetrate these areas better and stick well. The other parts of the chair like the legs may be left without sanding because the Teak oil on these parts wouldn’t experience much use.

The advantage of this method is that it saves time as you don’t need to sand all parts of the polyurethane. The disadvantage is that it doesn’t offer the proper adhesion and as such shouldn’t be used in high-traffic areas.

Final Words

Overall, you can apply polyurethane over Teak oil because Polyurethane doesn’t need to penetrate to stick. But, you shouldn’t apply Teak oil over polyurethane unless you remove or roughen up the polyurethane first. In both cases, you should remember to sand before applying the top coat.

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