If you’re looking for a protective coating to apply over acrylic paint, polyurethane is a common one to consider. However, not everyone knows whether you can use polyurethane over acrylic paint. Additionally, since several polyurethane versions are available, you need more information to ensure you select the best one.
Polyurethane can be used over acrylic paint. You want to make sure the acrylic paint is fully cured first. Additionally, you’ll need to choose the right type of polyurethane. Discoloration can occur when you use polyurethane over acrylic paint, especially if it’s oil-based.
By understanding how polyurethane impacts acrylic paint, you can make the right choice for your project. If you’re trying to figure out if you can use polyurethane over acrylic paint and which polyurethane is best for your situation, here’s what you need to know.
Can You Use Polyurethane Over Acrylic Paint?
You can use polyurethane over acrylic paint, but you want to choose the right version. Oil-based polyurethane has a gold tint. It’ll alter the hue of the acrylic paint, particularly white or pastel paint. Water-based polyurethane dries clear, making it a better match for most acrylic paint.
You’ll also want to select the right finish. While acrylic paint is typically a bit glossy when dry, polyurethane is available in many sheens. Since the polyurethane is acting as a topcoat, its finish determines the final look.
Additionally, you have to prepare the paint surface before you apply the polyurethane. Usually, you’ll need to use a cleanser to remove dirt, grease, and grime first. Then, you’ll need to sand the surface lightly to ensure the polyurethane binds properly.
Finally, you’ll need to follow the manufacturer’s directions for subsequent coats. You’ll often need to let the coat dry a specific amount of time before applying the next. Lightly sanding the surface between coats is typically necessary, too. However, each manufacturer may recommend a different process, so review the instructions before you begin.
Best Polyurethane for Acrylic Paint
Polyurethane is available in two types: oil-based and water-based. If you’re trying to choose the best polyurethane for acrylic paint, water-based is usually your best bet.
Both oil- and water-based polyurethane offer similar levels of protection, so quality isn’t an issue regardless of your choice. However, water-based polyurethane offers some other advantages.
First, water-based polyurethane is a low odor and cleans up with just a bit of water. Additionally, it dries quickly – usually in a couple of hours – allowing you to potentially apply several coats in a single day. Water-based polyurethane also dries clear.
Oil-based paint has a stronger odor and can’t be cleaned up with water. It dries slower – usually in five to 24 hours – potentially making it difficult to apply more than a single coat in a day. Further, oil-based polyurethane has a yellow tint when dry, altering the appearance of the paint color.
When it comes to the drawbacks of using water-based polyurethane, the biggest is the cost. Water-based versions are more expensive than oil-based polyurethane, at times doubling what you’ll need to spend.
Additionally, water-based polyurethane may require more coats, depending on where you’re applying it. It contains a lower percentage of solids, so more coats are necessary for ample protection. However, this is usually most relevant if you’re using it on a high-touch surface or in a high-traffic area, such as on a floor or tabletop.
How Soon Can You Use Polyurethane Over Acrylic Paint?
Before you apply polyurethane over any kind of paint, you need to make sure the paint is fully cured. That way, the paint is completely dry, and the polyurethane will go on smoothly.
Generally speaking, you’ll want to wait 24 to 72 hours before applying polyurethane over acrylic paint. Typically, that is enough drying time to ensure the paint is fully cured.
However, exactly how long you need to wait can vary depending on several factors. For example, high humidity can slow paint drying, leading to longer curing times. Whether you live in a humid climate or the paint is in a high-humidity environment, such as a bathroom, you may want to wait up to five days before applying polyurethane over acrylic paint.
If you live in a particularly warm and dry climate, acrylic paint can cure in less than 24 hours. But it’s still usually best to wait at least a full day before applying polyurethane.
In arid, hot climates, the surface of the paint may dry incredibly quickly. However, that doesn’t mean it’s dried thoroughly. By giving the paint at least 24 hours, you’re reducing the odds of applying polyurethane that seems dry but isn’t fully cured.
Another reason for needing the paint to dry fully is cleaning. Before applying polyurethane, you’ll want to clean the surface to remove dust, dirt, or other impurities. Otherwise, the polyurethane won’t stick correctly.
If the acrylic paint isn’t cured, the cleaning process could lead to smudges, streaks, or similar issues in the paint. If that happens, you may have to touch up the paint or fully refinish the surface, causing your project to take more time and energy.
Will Polyurethane Impact the Color and Finish of Acrylic Paint?
Polyurethane can impact the color of acrylic paint, depending on the type of polyurethane used and the acrylic paint color.
Oil-based polyurethane has a yellow or amber tint. When you apply oil-based polyurethane to essentially any color, that yellowish hue can influence the look of the acrylic paint. The color will take on a golden tint, making the shade warmer.
With incredibly light colors, the yellow tint from oil-based polyurethane may dramatically alter the look of the acrylic paint. For example, very pale blues may look green, and pastel purples may seem brownish.
Water-based polyurethane isn’t as likely to impact the color of the acrylic paint. Instead of a noticeable yellow tint, water-based polyurethane is far closer to clear. As a result, most hues of acrylic paint will maintain their previous look after applying water-based polyurethane.
However, there is one exception. With white acrylic, a slight yellow tint can occur even with water-based polyurethane. As a result, it usually isn’t recommended to apply polyurethane to white acrylic paint, regardless of the type.
As for the finish, both kinds of polyurethane can alter the look of acrylic paint. Acrylic paint tends to have a somewhat glossy finish when dry. When you use polyurethane over acrylic paint, the finish changes based on the type of polyurethane.
Polyurethane is available in a range of finishes, including flat, matte, satin, semi-gloss, and gloss. Once you apply polyurethane over acrylic paint, the acrylic paint will appear to have the same finish as the polyurethane. For example, if you use satin polyurethane over glossy acrylic paint, the final look is satin.
If you want to maintain the same finish as acrylic paint, satin or semi-gloss polyurethane could give you the proper sheen. Simply do a test patch to see which one is the best match.
How Many Coats of Polyurethane Should You Put Over Acrylic Paint?
The number of coats of polyurethane you’ll need to apply over acrylic paint depends on the type of polyurethane.
If you’re using water-based polyurethane, three coats is usually the minimum. However, you may need to go up to four or five to get a very smooth finish. Plus, if it’s a high-traffic area or high-touch surface, four or five coats increase the amount of protection. Water-based polyurethane has fewer solids. By adding coats, you increase the durability of the protective coating.
For oil-based polyurethane, there are more solids. As a result, you can get a suitable protective layer in fewer coats. For low-touch surfaces, just one or two coats might be enough. However, if it’s higher traffic, high-touch area or surface, three coats might be better.
As you add coats of oil-based polyurethane, it’s essential to understand that the yellow tint often gets stronger. Every layer thickens the polyurethane, so the golden hue ends up more noticeable.
Additionally, it’s also important to note that different polyurethane manufacturers might set their own standards. Read any instructions that come with the polyurethane before you apply any coats. That way, you’ll know what the manufacturer recommends, giving you a roadmap to follow.
How to Apply Polyurethane Over Acrylic Paint
Applying polyurethane over acrylic paint is a straightforward process. First, you need to choose a well-ventilated space. Additionally, you need to put on a breathing mask, eye protection, and gloves.
Next, you’ll need to prepare the paint surface. Once you know the paint is cured, use a trisodium phosphate solution to clean the paint. Follow the manufacturer’s directions to create the solution, then use a soft rag to wipe down the paint’s surface.
After the solution dries, you’ll want to scuff the surface lightly. Usually, 220-grit sandpaper will do the trick without creating deep scratches. Still, be gentle as you work and, once you’re down, use a damp rag to wipe away dust and debris. Wait for the paint to dry again.
At this point, you’re ready for polyurethane. Usually, you’ll want to use either a brush or a sprayer. Rollers can leave bubbles that can get trapped in the finish. With brushes or sprays, that isn’t an issue.
Apply one coat of polyurethane following the manufacturer’s directions. Let the coat dry fully, then lightly scuff the surface with sandpaper again. Wipe down the surface with a damp rag and let it dry before adding another coat.
Repeat the application, scuffing, and drying process until you reach the desired number of coats. Then, let the polyurethane cure completely before touching the surface.
Can You Spray Polyurethane Over Paint?
You can spray polyurethane over paint. In fact, spraying is one of the preferred methods. It’s easier to get a light, even coat with a sprayer. Plus, you won’t have to worry about bubbles.
If you’re going to spray polyurethane over paint, don’t thin the polyurethane. It’s naturally thin enough to work well in a sprayer, so there’s no need to take that step.
Before you start working, make sure any surface under, behind, or around the area you want to spray is protected. Polyurethane can soak through newspaper, so that won’t offer enough protection. Choose a more robust material.
Can You Seal Acrylic Paint on Wood With Polyurethane?
You can seal acrylic paint on wood with polyurethane. Typically, you’ll use the same process as you would with a fully painted surface. You’ll need to prepare the wood and paint before applying the polyurethane.
For the wood, you’ll want to sand the surface lightly to remove imperfections. Usually, 220 grit sandpaper will work in many situations, though you may want to start with 100 grit for deeper gouges, working your way up to a finer grit to create a smooth surface. When it comes to the paint, follow the preparation instructions above.
Once the sanding is done, wipe the surface with a cloth to remove dust. Then, you can start applying coats of polyurethane. Again, you can use the instructions in the paint application section above, as the process is the same for wood and paint once the first coat is in place.
Can You Use Minwax Polyurethane Over Paint?
You can use Minwax polyurethane over paint. However, since it’s oil-based, there can be a yellow tint after application.
If you’re concerned about yellowing, Minwax polycrylic is an alternative you may want to explore. It’s a water-based protective finish, so it is more likely to dry clear. However, it may alter the look of white acrylic paint, so it may not be ideal in that situation.
If you were wondering if you can use polyurethane over acrylic paint, the answer is mainly “yes” as long as you use the correct type for your project. In most cases, water-based is your best bet, as it’s less likely to have a yellow tint. However, using any polyurethane over white acrylic paint might not be wise as even water-based polyurethane may leave a yellow tint.
Did you learn everything you wanted to know about using polyurethane over acrylic paint? If so, share your thoughts in the comments below. If a friend, family member, or colleague could benefit from the information, feel free to share this article.