I’ve worked with polyurethane surfaces for years, and I know many people love its finish. However, not everyone feels the same.
If you’re thinking of repainting a polyurethane surface for a fresh color and finish, you might be wondering if it’s even possible. Well, I’ve got the experience and knowledge to guide you through this!
What to Know About Polyurethane
Polyurethane is another form of plastic but in liquid form. It is commonly used as a protective clear coat on a wooden surface and other materials. Polyurethane, once dried down, creates a hard and durable layer that protects the surfaces over time.
A polyurethane coating is commonly used among woodworkers due to its durable and protective nature. A polyurethane coating is sturdy, glossy, and clear, and you can get it in either water-based polyurethane or oil-based polyurethane options.
What Happens If You Paint Over Polyurethane?
Painting over polyurethane is a process. However, I do not recommend painting directly on polyurethane as the paint will just peel right off.
With the right steps, you can properly apply paint over polyurethane. Make sure to sand the surface properly using fine-grade sandpaper. Check surface imperfections before proceeding to clean, sand, prime, and paint.
The preparations will vary depending on surface conditions. Here are some polyurethane surface conditions you should note:
- Furniture that was well taken care of and had no damage.
- The furniture was neglected and had some scratches and requires more attention.
- The furniture is badly damaged, and the coats are peeling off. In this condition, you should not paint over polyurethane.
Sanding Process
The sanding process is simple all you need is sandpaper and a little elbow grease. Use finer grit sandpaper to sand down the surface and remove the original coat of polyurethane. A sanded polyurethane surface is important if you need to stain the wood with a different color.
If you have curved pieces such as those on a cabinet door, make sure to use a contour sanding grip. In this process of wood surface sanding, you need not remove all the paint or polyurethane, just enough for the new paint to stick on the surface.
Using a thin coat of mineral spirits and a rag, you can remove any debris as a result of the sanding process. Once you have accomplished this, you can go ahead and finish the other steps and paint the surface.
Can You Spray Paint?
You can spray paint over a polyurethane-coated surface. The spray paint will adhere to it as long as it has been cleaned, sanded, and primed. Make sure to use an oil-based primer to allow the spray to adhere more closely to the surface.
How to Assess the Condition of the Wood Surface Before Applying Poly
Assessing the condition of the wood with a polyurethane surface is one of the initial steps you need to do. The following criteria will help you determine if you can paint over polyurethane finished pieces:
Wear and Tear
Through visible inspection, check whether the surface has any signs of wear and tear. If there is minimal damage, then you will not have much problem. All you need to do is clean it. You may also apply a coat of paint if that pleases you.
If you find the original finish too glossy, you just need to lightly sand it and rub it down to result in a rougher texture. The resulting texture allows the paint to adhere to the surface.
Few Scratches and Neglect
When you have a surface that’s scratched up or hasn’t been cared for a long time, take the time to sand it down thoroughly. It’s essential to get it smooth and even before any painting, to ensure the best possible finish.
If you detect any crevices, you can use a wood filler or wood putty to fill cracks, gaps, and holes. Furthermore, you can paint over wood filler to fully cover the imperfections.
Once you have accomplished this, do not forget to clean the surface. Once the surface is clean can initiate painting the surface.
Severe Damages
If, unfortunately, your surfaces have severe damage, then you need to use a paint stripper. The stripper will remove the polyurethane coat. This stripping is necessary to achieve an even coat before applying a coat of paint.
How to Paint Over Polyurethane: 6 Easy Steps
Mastering the art of painting over polyurethane is straightforward once you know the ropes. The key lies in surface preparation, using the correct tools and techniques. Stick with me as I walk you through these steps:
Supplies & Tools Needed
- Clean cloth and clean rag
- Trisodium phosphate (TSP) solution for cleaning
- Mineral spirits
- Sandpaper with 150 to 180 grit
- Liquid sandpaper or deglosser (optional)
- Sanding machine for larger surfaces
- Oil-based primer
- Paint that you prefer
- Bristle scrubbing brush or polyurethane paint brushes
Step #1: Ensure Safety
Make sure to keep in mind your safety before proceeding with the process. Prepare the following safety gear:
- Respiratory mask
- Safety gloves
- Safety goggles
- Protective clothing
Once you have the items follow these guidelines to ensure safety.
1. Wear protective gear
It is always best to wear protective gear, especially since surface preparation before painting over polyurethane is essential. The preparation involves sanding and the use of chemicals.
Make sure to wear a mask to prevent inhaling sawdust during sanding and fumes from chemicals. Also, wear eye protection at all times. Make sure to wear rubber gloves to protect your hands as well.
2. Work in an area that is well ventilated
Make sure to work in an area that is well-ventilated. This will ensure proper air circulation throughout the process.
3. Check the weather
Include in the plan the weather. Check the weather and make sure to work during the days when the weather is good and fair. The state of the weather also contributes to the drying time of the paint.
4. Ensure proper disposal of materials
Prepare receptacles for the disposal of materials. During this process, you will need to dispose of excess cleaning solutions, paints, and primers which can become hazardous if not contained properly.
Make sure to read the product labels or the manufacturer’s guidelines for instructions regarding the proper disposal of the products.
5. Avoid smoking or Remove any combustible items near the paint
Throughout the process, you will be dealing with combustible material, so make sure to keep it away from smoke and other things that can increase the risk of it turning into flames.
Step #2: Preparing the Wood Pieces & Removing Any Hardware
It is also very important to prepare the wood and the surface before prepping and treating it. Make sure to remove any accompanying hardware, such as knobs, other metallic pieces, and even the cabinet door.
Initially, clean the entire surface of the wood, including dust, oil, mildew, and grime, with a dry cloth. Next, use a TSP solution to clean the surface.
Dilute one-quarter of the TSP solution to one gallon of water. Soak your sponge in this solution and squeeze out the excess solution.
Rub down the surface in a circular motion until you find that there is no dirt left. Brushes are oftentimes used to remove marks or dirt that are too hard for the sponge.
If you are sensitive to TSP, you can opt for the alternative. You can dilute a tablespoon of dishwashing liquid into a gallon of water. This solution is less risky for health. You can also use mineral spirits as long as there are no traces left behind.
Step #3: Sand and Clean the Surface
To properly prepare the surface, proceed to sand down the surface once it is completely cleaned of dirt and grime. All you need is sandpaper and a little elbow grease.
Sanding down is important to the longevity of the project. Sanding down also results in an even and smooth surface. A sand-down surface also ensures that paint sticks to it.
Make sure to wear safety gear and adhere to safety precautions throughout this process. Wear safety goggles, gloves, and a mask before taking on any task.
If you observe that the coat has a yellow hint on the original polyurethane coat, proceed to use sandpaper with 60 to 80 grit. At the end of the sanding, you should get a slightly rough or gritty surface.
If you are sanding the surface by hand, continue to sand in a circular motion. If you are done sanding, it is time to clean up the debris left behind. Use a cloth and some mineral spirits to wipe down any remaining debris.
If you want remove the old paint or finish, here’s how you can use Citristrip stripping gels for better results.
Liquid sandpaper has a lot of chemicals in its formula, making it quite toxic. There are certain safety precautions to follow if you will use this.
Step #4: Apply a Coat of Deglosser
An optional step is to apply a coat of deglosser. A deglosser is commonly known as liquid sandpaper. It acts like sandpaper with a very fine grade. It is a very powerful solvent, so make sure to wear protective gear.
Before applying it to your material, test it out first in an inconspicuous area. Apply a thin layer on the surface and see if there are any adverse reactions if there are none, then go ahead and use it on the material completely.
Once you have decided to apply the deglosser, you have the option not to sand the surface anymore and proceed to paint the surface. Proceed to use mineral spirits to remove all the dust from the surface.
Step #5: Prime the Surface
If you opt not to use a deglosser, you need to sand the surface. Priming is crucial at this stage. A good bonding primer ensures the paint adheres well to the polyurethane. Beyond just aiding adhesion, a high-quality primer also offers an extra protective layer. Personally, I’ve had great results with Zinsser or Kilz Primer for this process.
Before you dip your brush into the primer, it’s essential to select the right type first, based on the original coating and the type of wood you’re working with.
I always lean towards an oil-based primer for this job. From my experience, water-based primers just don’t gel well with polyurethane finishes. When you’re shopping for an oil-based primer, prioritize one that’s of premium quality and known for its superior bonding properties.
Oil-based primers require brushes with natural bristles for primer application to smaller areas. However, if you have a larger area, you can use a paint roller. Use continuous up-and-down brush strokes when applying a primer.
Once the primer has dried, sand the surface to give it a bit of scuffing up.
Step #6: Paint the Surface
It is now time to paint over polyurethane. Do this step, especially if you have successfully applied the primer or deglosser. Follow the aforementioned steps to get your paint to stick to the surface.
Oil based paints are known to be more durable and long-lasting. However, oil-based paint emits a stronger odor and takes a longer time to dry.
Water-based paint, on the other hand, does now have an odor and dries more quickly. However, they are not as durable.
If you have the luxury of time, it is always best to use oil-based paint. Oil based paint extends the lifespan of the material and makes it more durable as well.
For harder-to-reach areas and smaller ones, you can go ahead and use a small brush. However, if you are dealing with larger areas, I recommend using a paint roller with foam or a spray gun.
Now, you can start painting over polyurethane. Once you have applied the first coat of paint, allow it to completely dry before applying the second coat.
Make sure to apply long and even strokes on the first coat as well as on the second coat. Check the can of paint for the number of recommended coats.
Make sure to give the paint, or at least after the final coat, overnight to finish the drying and curing process. Make sure to apply the same brush path to the final topcoat.
When the coats of paint have dried down completely, remove any dirt using a clean cloth. Now you have a fresh coat of new paint on your wooden piece.
You can also go the extra mile and add a fresh coat of polyurethane over the paint. This will give a polyurethane finish. The polyurethane finish not only gives it a glossy coat but also extra protection.
Also Read:
Types of Paint to Apply Over Polyurethane
The question of painting over polyurethane isn’t just about the preparation. It’s equally important to understand which paints work best atop a polyurethane finish. Let’s delve into the various paints available and help you decide which are most suitable and which should be avoided when painting over polyurethane.
| Type of paint | Can or Cannot Be Used Over Polyurethane | Remarks/ Description |
| Latex paint | Can be used | Not always the preferred paint for polyurethane |
| Acrylic paint | Can be used | Preferred paints for polyurethane and is non-toxic |
| Oil-based paint | Can be used | Strong fumes and dries slowly |
| Water-based paint | Can be used | Environmentally friendly and dries fast but not as durable |
| Enamel paint | Can be used | Durable paint and dries fast |
| Chalk paint | Can be used | Requires specific surface preparation prior to its application |
Latex Paint
Latex paint is not particularly a go-to paint for polyurethane. It can still be applied over the surface as long as the necessary steps like cleaning, sanding, and priming has been accomplished before its application.
However, latex paint is water-based, whereas polyurethane is not. You need to use the right primer to ensure the paint will stick.
Related Articles:
Acrylic Paint
You can certainly apply acrylic paint on a polyurethane surface. With its water-based composition, acrylic paint adheres well to the smooth surface of polyurethane, creating a durable and long-lasting finish.
However, make sure to perform the necessary steps before its application.
Oil-Based Paint
Oil-based paints are highly recommended paints for jobs, especially if you have the luxury of time. These paints are durable and allow the material to last a long time. However, oil-based paints emit a strong odor and take a long time to finish.
Water-Based Paints
Water-based paint has a lower concentration of chemicals which is good for the environment. It dries quickly. However, it is less durable compared to other paints in this list.
Enamel
Enamel has one of the best formulations. It is very durable like oil-based paints and dries quickly as water-based paint does. Enamel is an excellent choice if you wish to have a tough surface similar to that of polyurethane.
Chalk Paint
You can also use chalk paint [1] on polyurethane. Similar to other paint options, chalk paint will stick to polyurethane. However, prior to its application, the surface needs to be prepared to make sure the chalk paint stays on the surface.
How to Use Chalk Paint
Clean the surface to remove all the dirt, dust, oil, and grime. Sand the surface using fine-grade sandpaper or 200-grit sandpaper. Clean the surface for excess debris. Apply the primer on the surface then apply a coat of chalk paint.
FAQ
Can you paint poly over varnished wood?
You can paint polyester over a varnished wooden surface as long as the wood surface has been cleaned, primed, and sanded. If these steps are done on the surface correctly, you can go ahead and apply a coat of paint.
Read More: Can You Apply Water-Based Polyurethane Over Oil-Based Stain?
Do I need to prime poly before painting?
Yes, you need to prime the polyester before you paint over polyurethane. This allows the paint to adhere properly to the surface.
What’s the recommended primer before painting over polyurethane?
There is a lot of high-quality bonding primer products available, however, the most recommended primer to use before painting over polyurethane is an oil-based primer.
Conclusion
Most furniture pieces have a glossy polyurethane finish to it, and if it has been sitting in your home for a long time, it might need a fresh coat of paint.
Luckily, you can paint over polyurethane-finished furniture as long as you know the proper steps to prepare the surface. Hopefully, this guide has shown all the necessary points you need to know about painting over polyurethane so you can maintain your pieces properly!
Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You’ve probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.
Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.
