Polyurethane Over Teak Oil (Can You Do it & How To)

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 over to increase the durability of the teak oil. Polyurethane doesn’t need to penetrate the surface to stick, so polyurethane will stick over the teak oil layer. However, you must sand before applying the polyurethane. 

On the other hand, you can’t use teak over polyurethane. That’s because teak oil needs to penetrate the surface to stick, and polyurethane prevents moisture (including paint) to penetrate its coating. So you must remove polyurethane before applying teak oil.

Polyurethane Sticks To Teak Oil

Polyurethane sticks over teak oil because polyurethane is a topical sealant that doesn’t need to penetrate a surface to stick. So, if you apply polyurethane over teak oil, the polyurethane will stick over the teak oil coating. 

However, you must lightly sand teak oil before applying polyurethane. Sanding creates tiny ridges on the teak oil coating that helps polyurethane stick better. 

To get a better result, you must use water-based polyurethane instead of oil-based polyurethane. That’s because oil-based polyurethane penetrates the surface deeper than water-based polyurethane.

Teak Oil Dry Time Before Applying Polyurethane

Teak Oil Dry Time Before Applying Polyurethane

You must allow teak oil to dry (or cure) for 12-24 hours before applying polyurethane. This is because teak oil must harden (become rigid) before polyurethane can stick over it. 

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, the dry time of teak oil depends on the humid levels, the number of coats, and the thickness of the coat. 

If you apply polyurethane before teak oil dries, the teak oil finish will turn sticky. That’s because if the teak oil is still wet (not dry) and you apply polyurethane over it, the evaporation process of the paint solvent will be stopped. This will cause teak oil to bleed through and stain the polyurethane clear coat. 

Also, the teak oil coating must be rigid because you have to sand it before applying polyurethane over 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 polyurethane over teak oil, you must prep the teak oil coating. 

Also, you need a few tools and supplies:

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

1. Clean and Degrease The Teak Oil

Clean and Degrease The Teak Oil

First, remove grease, oil, dust, and grime from the teak oil coating. If the teak oil coating has grease or grime, the sandpaper will get clogged with filth. 

To degrease teak oil:

  1. Use a cleaning solution or degrease such as WD-40.
  2. Apply the degreaser over teak oil.
  3. Use a soft brush to wipe off the dust and grease from the teak oil.
  4. Remove degrease residue using clean water.
  5. Leave the teak oil to dry. 

2. Sand The Teak Oil

Sand The Teak Oil

Once teak oil dries, you must sand it. Sanding will remove bumps and imperfections from the teak oil coating so the polyurethane can dry properly. To sand teak oil, use fine-grit sandpaper. 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. 

3. Apply Primer (Optional)

Apply Polyurethane Paint Primer

If you don’t want the teak oil color shade to show on the finish, apply a primer before polyurethane. Polyurethane is a clear coat, so the color shade of the finish won’t be changed. However, a primer will cover the teak oil color shade. This means the finish will have the same color as the primer. 

Also, a primer will help polyurethane stick better over teak-oiled wood. Latex primer works best for sanded teak oil. 

This step is optional, so you can skip it. 

4. Apply The Polyurethane

Apply The Polyurethane

Once the teak oil is clean and sanded, apply the polyurethane. For spray-on polyurethane, spray the polyurethane over the teak oil coating evenly. For regular polyurethane, use a bristled paintbrush or a paint roller. 

You must thin oil-based polyurethane with mineral spirits before applying it over teak oil. This makes the polyurethane coating lighter, easier to control, and helps it to dry faster. 

You must apply 2-3 coats of polyurethane over teak oil. 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. That’s because teak oil has a large deposit of natural oil compatible with oil-based polyurethane.

Oil-based polyurethane is thicker than Teak oil. So, use more teak oil in the mixture or thin the mixture with turpentine to make the 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 in the teak oil.

Also, water-based polyurethane and teak oil 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 teak oil can’t stick to polyurethane. Teak oil doesn’t stick to polyurethane because teak oil is a penetrating finish.

This means teak oil needs to penetrate a surface to stick to it. But, the moisture-resistant finish of polyurethane won’t allow any moisture (including paint) to penetrate its coating. This means the teak oil won’t be able to stick to polyurethane. 

To apply teak oil over polyurethane, you must sand the polyurethane or remove it. Sanding the stress areas of polyurethane will create holes (spaces) for teak oil to penetrate to. However, the bonding between polyurethane and teak oil won’t be good. 

So, it’s best to remove the polyurethane coating completely, and then apply teak oil.

Final Words

You can apply polyurethane on teak oil because polyurethane doesn’t need to penetrate the surface to stick. This means polyurethane will stay (stick) over the teak oil 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 teak oil over polyurethane, the teak oil won’t stick and will slide off the glossy finish of polyurethane.

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