Can You Put Polyurethane Over Paint?

Polyurethane-painting-wood-desk

Homeowners are always skeptical about what they paint and how to protect the paint on their wood. And it’s no surprise—everybody is looking for how they can cut costs and get something that’ll last for the long term.

One question I often get all the time—can you put polyurethane over paint? Nobody wants trials and errors, so you must get it first before trying out anything. In this post, I’ll answer this question and a lot more related to it.

Can You Use Polyurethane Over Paint?

Yes, you can use polyurethane over paint as it can help protect the paint on your wood. For example, oil-based polyurethane is an excellent option when looking for a smooth finish, though you’ll have to wait longer for it to dry. In a nutshell, you can use polyurethane over any type of paint, as long as you clean it before using the poly.

While it’s true that you can use polyurethane over paint, you don’t have to paint your wood or surface before you can apply polyurethane to it. However, if you’re looking for a solid color, polyurethane is the best option for you. Since polyurethane can adhere to acrylic and latex paint, feel free to use it on these as long as you have the surface cleaned before.

Polyurethane comes as an excellent option for many homeowners, but please note that it might not be great for colored or white paints. The good news, though, is that you can use polyurethane for refinishing your furniture to the best natural look you have always admired. If you are wondering whether or not you can apply polyurethane over glossy paint, yes, you can.

What is Polyurethane?

Polyurethane is a petroleum-based product that’s used mainly by homeowners as an adhesive or for coatings. It is available in two forms—water-based polyurethane and oil-based polyurethane. Oil-based poly will get you an amber color and takes a little bit longer to dry.

On the contrary, water-based polyurethane does not give any amber color and will dry much faster than oil-based poly. The downside to water-based poly is that it’s a bit more expensive than oil-based poly because it can resist chemicals and heat.

That is why you must be cautious not to use the water-based poly on surfaces that will most likely be exposed to direct heat or any chemicals. However, if you are looking for poly that can withstand intense heat and chemicals, oil-based poly should be a good choice.

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Can Polyurethane Be Used Outdoors?

Yes, you can use polyurethane for outdoor surfaces, but you’ll need to ensure that the label is indicated as “for exterior use” and that it is resistant to UV.

Outdoor poly is manufactured in a way that they can allow for contraction and expansion when there are fluctuations in temperature.

What Kind of Polyurethane Should You Use?

There are two types of polyurethane—water-based and oil-based. Depending on your needs and preferences, you will settle on either of the two. However, let’s dig in to see what options and features each of these will offer you, depending on your preferences.

If you are looking for poly with no odor and takes a shorter time to dry, water-based poly will be the best option for you. Water-based polyurethane is manufactured for surfaces that are usually exposed to temperature fluctuations.

Sometimes you’re looking for a poly that doesn’t need many requirements, such as a respirator. If this is the case, water-based poly will be an excellent choice. Besides, water-based poly doesn’t produce odor, such as oil-based poly.

Oil-based poly will be your best bet if you’re looking for a scratch-resistant and something excellent for abrasion. Because oil-based poly is scratch-resistant and suitable for abrasion, most homeowners prefer wood floors, cabinets, or even railings.

Finally, if you are looking for some fancy colors, such as golden, yellow, or even brown, get an oil-based poly, and you’ll be sorted. In a nutshell, you can opt for any of the polyurethane, depending on your preferences and your overall objective.

How Can I Get the Best Results With Polyurethane?

You may not require sanding during adhesion, but it’s still an important step. Sanding can help remove any dust or brush strokes that can look bad on a wet surface. Your surface will end up rough, and that’s the last thing you want as a homeowner.

Wondering what the best sandpaper is for this process? 320 grit sandpaper has proven the best over the years. It sands the surface you want to work on thoroughly, making it very smooth and ready to work on. You can also look for other options, depending on your budget and preferences.

How Long Should Paint Dry Before Applying Polyurethane?

You should wait between 24 and 72 hours before you can apply the poly. Within this timeframe, you are assured that your paint has dried and ready for polyurethane.

In some cases, you might even want to wait longer, especially if you are looking for the best results. You want to leave it to dry to avoid any complications.

Your waiting time will depend on several factors—the ventilation required, the type of paint you are using, the wood type, and the weather or atmospheric conditions.

If your paint doesn’t dry properly, but you still go ahead to apply the poly, the chances are that it will work against the paint, leaving a rough finish that you didn’t want.

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And because polyurethane is designed to protect the paint from fungus, dirt, or water, it won’t be effective on your surface if you apply it when the surface is still wet.

For paint on your surface to be termed as dried, the solvents must have evaporated from the coatings. Besides, you’ll be able to prove the same by touching to feel.

Can You Put Polyurethane Over Chalk Paint?

Yes, it’s fine to put polyurethane over chalk paint as poly is watertight, durable, and reasonably affordable. However, you must note that applying poly over chalk paint could result in the surface turning yellow over time.

One of the best polyurethanes you could opt for is water-based polyacrylic. You can apply this type of poly using a brush, or you can spray it. Polyacrylic is easier to use and has many features that oil-based poly has.

You can also use paste wax over chalk paint, which gives the best smooth and deep finish. It can enhance color, making it better than paint. With all these options, you still have to choose what works best for you.

Can You Put Polyurethane Over Latex Paint?

Yes, you can use polyurethane over latex paint—whether you are using water-based or oil-based poly. However, you should note that oil-based poly will turn yellow over time, while water-based poly will remain transparent even as it ages.

Therefore, the best recommended poly for latex paint is water-based polyacrylic. It will give you the best protective finish and last for longer. Besides, this water-based polycrylic has the best sealant features, and rest assured you’ll get value for your money.

In most cases, when you are painting your furniture, you’ll need to give it a protective finish to enable it to last longer. However, you might not need a sealer if you won’t use the surface of the furniture you are painting regularly.

Can You Put Polyurethane Over Acrylic Paint?

Yes, you can put polyurethane over acrylic paint, and this doesn’t matter whether you’re using water-based or oil-based poly. Most homeowners use poly over acrylic paint to get back the bright and glossy finish their surface had previously.

Usually, acrylic paint dries wet and darker, which is why adding a top coat gives it the bright and glossy finish every homeowner would wish. Besides, just bringing back the brightness, poly will also protect the surface from dust that might build up after some time.

Finally, you want to add polyurethane to maintain the color of your surface. Most surfaces will lose their color over time and may look dull. To prevent this, most homeowners opt for polyurethane to maintain their surface’s color.

Step by Step Process to Apply Polyurethane Over Paint

If you’re dealing with fresh paint, let it cure first before coating. Curing times may vary depending on the paint type and atmospheric conditions, but you’ll want to leave it for about a week for complete effectiveness.

Step 1 – Wash the Painted Surface

If you’re working on older paint, use a robust detergent solution to wash off the stains. Then, mix ½ cup of trisodium phosphate with a gallon of water and scrub thoroughly using a sponge. This will degloss the surface and clean it, allowing polyurethane to adhere better to the paint.

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Step 2 – Scuff the Surface

Allow the paint enough time to dry, then sand with 120-grit sandpaper to engrave the surface. The key is to flatten the gloss without creating visible scratches slightly. You can use a hand sander if you’re working on a smaller surface and a buffer if you’re painting polyurethane over a painted surface. Wipe down any sanding dust with a damp rag or tack cloth.

Step 3 – Choose Your Applicator

Apply oil- or water-based polyurethane with a brush, or spray it. Avoid using a roller—it leaves bubbles that may harden into the finish. Do not thin the polyurethane before spraying it—it’s thin enough to spray out of the can, and adding more thinner may cause it to run.

Step 4 – Apply One Coat, Then Scuff

Allow the first paint layer to dry for the recommended time, then sand it lightly with 120-grit sandpaper. Sanding eliminates dust particles as well as flattening the bubbles that may have formed into the coating.

Step 5 – Apply a Second Coat

Apply a coat or two and allow enough time for the final coat to dry completely. A good rule of thumb is to give it an additional 24 hours to harden before handling your painted structure.

Frequently Asked Questions

1. Can You Put Polyurethane Over White Paint?

Yes, you can apply polyurethane over white paint, but it will turn yellow as it ages. While it’s an excellent finish for wood fixtures, polyurethane is ineffective for bright-colored paints. You can use polyurethane for refinishing furniture to natural wood colors. 

2. Do You Sand Paint Before Applying Polyurethane?

It’s a good idea to sand in between coats of polyurethane, but you need to ensure that the paint is completely dry and dust-free. Sand the surface lightly, vacuum it and then wipe it down using a lint-free cloth to eliminate sanding dust.

3. Can You Put Clear Varnish Over Painted Wood?

Yes, you can apply clear varnish over painted wood, but it won’t adhere properly to oil-based paint without first priming the surface. If the paint rubs off, it’s often oil-based and needs a water-based primer before adding the varnish. 

4. Can You Apply a Clear Coat Over Paint?

Yes, you can apply a clear coat over an enameled fixture as it adheres well to enamel paint. You can also apply water-based acrylic clear paint over enamels but will yellow with age, especially when used over light colors. 

5. Which Is Better Polycrylic or Polyurethane?

Polyurethane is better than polyacrylic for two reasons. First, it’s durable and adheres well to surfaces. Second, polyurethane is versatile and can be used on both interior and exterior surfaces. On the contrary, Polycrylic can only be applied on interior surfaces. Plus, it’s less durable than polyurethane.

Conclusion

Yes, you can put polyurethane—whether oil-based or water-based. Depending on your preferences and your objective, choose the best polyurethane to use on your surfaces.

If you want poly that would dry fast, water-based poly is the best choice. On the other hand, if you need poly that’s scratch-resistant, oil-based poly is your best choice.

About Sarah Walker

Sarah is a homemaker and is passionate about fixing little things in and around her house. She loves to do DIY hacks and keeps on writing about those things in her blog. When she is not writing, she keeps herself busy with her twins Cathy and Mickey.