When it comes to the type of finish to add to their acrylic project, artists seek the right information. Crafters working with wood, especially, are curious to know if it’s appropriate to put polyurethane varnish on acrylic paint. Knowing this will save them a lot of time and resources. This article will help us unravel this concern.
What is polyurethane?
As the name implies, polyurethane is a rigid or flexible plastic material made from the organic composition of various ingredients. The polymer material is useful in a wide range of applications. For artists, polyurethane varnish is perfect for insulating their projects against damage done by dust, yellowing, debris, and UV rays.
As a type of resin material of choice, polyurethane varnish comes as a liquid coating. As a finishing layer, the material will protect both the interior and exterior of a wide range of surfaces. Such surfaces include wood, canvas, parquet, hardboard, plywood, and more.
What type of paints work over polyurethane?
Typically, acrylic paint works perfectly to paint polyurethane surfaces. Alternatively, oil-based enamel also does a lot of magic on polyurethane-treated wood surfaces. Acrylic latex paint is a great option if you want to paint the primed exterior part of polyurethane-treated wood. Acrylic and oil-based paints are the best because they are resilient and durable. They can endure a lot of duress.
However, make sure you clean the surface properly, using a damp mild cloth. In addition, you should abrade the polyurethane surface with a fine-grade (about 120-grit) sandpaper. This will help the paint and primer to adhere well to the surface.
Can you put polyurethane over acrylic paint?
The straight answer is yes. Polyurethane works excellently on acrylic paint. it doesn’t matter whether it’s a water-based or oil-based coated finish. Adding polyurethane varnish to your acrylic makes it regain its brightness while also offering a silky varnish. However, oil-based polyurethane varnish can give some poor yellow coloring to your paint. Perhaps, you should stick to water-based varnish.
How long should paint dry before you apply polyurethane?
On average, the wait time before applying the polyurethane coating on your acrylic paint should be about two hours. Usually, it’ll about an hour for the paint to dry. You can varnish after holding on for another hour. The good news is that it’ll take less time if you properly sand and prime the polyurethane surface. In the end, it all depends on the temperature of where you work.
What will happen if polyurethane topcoat was applied over acrylic paint?
When you put the polyurethane topcoat on your acrylic paint, you’ll notice that the paint will put on the coat texture of varnish. By implication, if you apply matte polyurethane varnish over acrylic paint, the paint’s final effect will be matte. Polyurethane topcoat outshines the look of the paint.
How to apply polyurethane over Acrylic Paint?
Applying polyurethane varnish on your acrylic paint is pretty straightforward. Once you’re ready, the following step-by-step guide will help you achieve the best result.
Supplies needed:
- Safety goggles and gloves
- Sponge
- Sandpaper (120 or 220-grit)
- Paintbrush or roller
- Vacuum cleaner
- Polyurethane (water-based or oil-based)
- Water and detergent
- Mild tack and fluff-free cloth
Applying polyurethane over acrylic paint:
- prepare the wood surface: clean and sand
Using trisodium phosphate or detergent, clean the painted wood surface. This will help to remove grease or grit on the surface. In addition, it will reinforce the proper adhesion of the polyurethane varnish to the surface.
After cleaning and removing grease, the next step is to sand the surface and get rid of scratches, bumps, or goopy spots. Use 120-grit sandpaper. Make sure the sandpaper flatten the in-paint sheen - Do a deep cleaning
Then you have to tack the wood surface. Simply dip a fluff-free cloth inside the water to clean the sanding residue. Alternatively, you can use the vacuum cleaner to achieve the same result.
- Apply polyurethane varnish
After smoothening and vacuum cleaning, the next line of action is to apply the topcoat. Make sure you apply the coat in thin layers. It should not be dense or too thin. The roller, paintbrush or spray will do this job properly.
Then, leave the varnish to dry for at least an hour. - Sand the surface & Remove sand residue
Once the one hour elapses, the next thing to do is to sand the dried varnish surface. This time, you should go for 220-grit sandpaper. It will do a better smoothening and flattening job than the 120-grit counterpart. Get rid of all scratches, dust, debris or particles.
Now, it’s time to clean the painted surface. Make sure you take off all sanding residue or small grains of particles or dust - Apply the second layer of polyurethane
You may observe that the first layer of the polyurethane coat isn’t enough. You should apply the second thin layer of the varnish. Allow it to dry for another one hour or so before repeating steps 1 and 2 of procedure 3.
Best polyurethane for wood: Varathane 2006IH Water-Based Polyurethane Gloss Finish
If you need a tough varnish that will restore the brightness of your acrylic painting, this guy is the right pick. It is designed to protect the interior surfaces of your wood project. It is applicable on a wide range of surfaces, including cabinets, trim, windows, furniture, and more. This liquid polyurethane formula gives off a glossy finish, giving your project a polished and fine look. What’s more, it is durable, water-resistant, and with a clear finish.
The icing on the cake is that this water-based varnish dries very quickly. It dries to the touch in less than half of an hour and has a wider coverage of up to 2.9 square meters. Guess what? You can also clean it up fast with soap and water.
Pros
- Easy to clean with water
- Glossy and polished finish
- Dries fast and won’t yellow
- Suitable for indoor use
Cons
- May not be crystal clear when it dries
Tips When Painting Over Polyurethane
Here are things to keep in mind to achieve the desired result when painting over polyurethane varnish:
- Wear protective gear, for example, goggles and rubber gloves
- Clean the workspace and remove all cabinet doors
- Get all supplies ready before you start
- Clean and sand polyurethane surface
- Allow the coat to dry
- Apply coat in thin layers
- Apply oil-based primer to prime the surface
- Allow the primer to dry overnight
- Paint the coat and allow it to dry
- Use fine-grade (120-grit and 220-grit) sandpaper
Final Thoughts
Using polyurethane coatings on your paint help to bring out the brightness and prevent it from having a dull look. Apart from polyurethane topcoats, there are other safe-to-use varnishes you can apply over acrylic paint. It all depends on your project and the result you seek. You can use shellac coatings, spar varnish, acrylic resins, acrylic polymer, or lacquer.
