After you have done the painting work, and after spending all your time gluing, painting and sanding, you still have a task pending. This task indeed helps in enhancing the look and ambience of the painted surface. This is applying polyurethane all over the surface, after painting it. If you have decided to add polyurethane over paint, then you can go with water-based and oil-based polyurethanes.
To gain the best results, it is beneficial to add at least two or three drops of the same color paint to the polyurethane. This helps in enhancing the cloudy look on the surface, that is just been painted. Also, before polyurethane over the painted surface, it is mandatory to make sure that the surface is free from debris and dust.
Before applying polyurethane on the painted surface, it is important to keep in mind that it is likely to turn yellow when you are applying it over light-colored painted surfaces. If you are using water-based polyurethane, then we can be sure that it will stay clear on all types of painted surfaces.
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Does Paint Require The Application Of Polyurethane?
- All types of paints will require a clear coating finish. But the type of paint that you choose can either mandate or eliminate the need for polyurethane. The paint products that are recently available in the market eliminate the need for polyurethane.
- Though the recently available products advertise themselves to be an all-in-one product that functions as both paint and protector, it is still better to apply two coats of polyurethane. This helps in rendering additional protection to the surface that has been painted.
- If you are painting the surface with the help of oil-based and enamel paints, then be notified that these paints are extremely durable. Thus polyurethane is not required on these surfaces, as these paints are capable of handling excess traffic and use. But applying a layer of polyurethane will render it a glossy and shining finish.
How Long Should I Wait Before Applying Polyurethane After Painting?
- The best option is to follow the label given by the manufacturer of the paint, to learn exactly how long to wait before applying a coat of polyurethane. In some instances, the paint labels will not have any information about the drying time of paint coats. In such instances, it is beneficial to follow the re-coat time on the paint label. And this time varies from one painting to another.
- The best option is to wait for a time of about four hours, before applying the coat of polyurethane with the help of a sprayer. If you are applying a coat of polyurethane on the furniture or any surface, you should wait for a minimum of 24 hours. The longer the drying time you give for the polyurethane, the lesser will be the damage caused to the paint, while applying the polyurethane coating.
- you have to make sure that you are not touching the surfaces while spraying the polyurethane paint. If you touch it, you are messing up with the paint. You can mitigate the drying time by a few hours, if you are applying the paint with the help of a sprayer and if you are painting with the help of water-based polyurethane. Before applying the layer of polyurethane, it is important to make sure that the surface that is been painted already is dry to touch completely.
- The drying time of the paint and the polyurethane layer is also affected greatly by temperature and humidity. Thus, it is important to make sure that the paint layer is dried up completely, before applying the coating of polyurethane. Paint takes a lot of time to cure. Thus, the longer the wait time, the better will be the finish. The paint will also become scratch-resistance later on.
- Similar to paint, polyurethane also takes a lot of curing time. And thus, it is important to give it some time to dry after applying polyurethane, before using the object. Polyurethane takes about 30 days to completely harden and fully cure.
Advantages Of Using Water-Based Polyurethane Over Oil-Based Polyurethane
1. It is beneficial to use water-based polyurethane over oil-based polyurethane, for painting different surfaces. It is considered that oil-based polyurethane is extremely durable than water-based paints.
Also, water-based polyurethane can be exceptionally durable. The water-based polyurethane is good to use over floors that are made of hardwood, and such floors become extremely durable as well.
2. Some of the water-based polyurethane paint coats are also found to be stronger than the oil-based polyurethane paint finishes. The water-based poly is quick and easy to touch.
At an ideal temperature, it takes about one hour to dry. If you are trying to spray the coats, then you can reapply the coats over painted surfaces, within a few hours.
3. Choosing water-based polyurethane also has other advantages over oil-based poly. They are easy to clean and they can be mixed with water for thinning, before spraying.
This makes the entire painting process much easier. For example, thinning the water-based polyurethane with only 10% water before spraying will help offers a nice and smooth finish.
4. The oil-based polyurethane has to be thinned with the help of a paint thinner, and this costs more than mixing it with water. The cleaning process with the oil-based poly is quite difficult. You can make use of mineral spirits to clean up oil-based poly. But you should take care to dispose of these chemicals effectively.
5. Also, oil-based polyurethanes have a stronger odor than water-based products. Breathing the oil-based polyurethanes could also be very dangerous for the lungs.
can i put polyurethane over paint? [Step-By-Step]
The process of applying a layer of polyurethane over paint is complex, then applying it directly over a wooden surface. While spraying them over painted surfaces, it is required to be extremely careful. When applying polyurethane over paint, you can easily see streaks, then apply over wood.
If you apply polyurethane directly over wood, you can see that it will get absorbed into the surface. Let us discuss the step-by-step process of applying polyurethane over surfaces that are painted, with the help of a foam applicator and a sprayer.
1. Ensure The Paint Is Dry
The first step is applying a coat of polyurethane on a painted surface, is to make sure that the surface is completely dry. If the paint is wet, you will end up wiping the wet paint thus ruining the finish of the paint.
You may have to sand the surface again and then repaint the surface. After painting, it will be hard to say, if the surface is dry or wet. Waiting for the paint to dry for a long time is a good idea.
2. Clean The Painted Surface
Before applying the polyurethane, make sure the painted surface is free from visible dirt. Anything that we can see through the pain, will easily be visible through the polyurethane. It is beneficial to use a tack cloth and wipe the surface, to clean it off the dirt.
It is a bad idea to make use of any cleaning products, over the painted surface, as it will get the paint wet. Using cleaning products will ruin the adhesion of polyurethane.
3. You Can Try Super Light Sanding
It is not recommended to sand the surface to be painted at this point, as it might scratch the paint. But if required, you can perform a slight scuff with the help of a higher grit sanding sponge. This helps in preserving the texture of the surface that is painted.
4. Mix A Few Drops Of Paint In Polyurethane
It is also recommended to mix a few drops of paints on the polyurethane so that, it renders a cloudy finish in its final painted project. This could be highly effective while painting using dark color paints.
5. Applying The Polyurethane Coating
It is better to apply the polyurethane coating with the help of a paint sprayer. Before applying the paint, it is good to thin the water-based polyurethane at about 10%.
It is also beneficial to apply the polyurethane coating with the help of an applicator made of foam or a brush. Making use of the applicator will help in rendering the smoothest finish on the painted surfaces.
Depending on the type of paint that we are using, it is beneficial to apply two to four coats. If required, you can apply additional coats. You can also perform slight sanding in between the coats, with the help of a 300 grit sanding sponge.
6. Allow The Paint To Dry
After applying the paint coating completely, you should allow the surface to dry overnight. This will allow additional time for the polyurethane to harden, and ensure that it doesn’t scratch easily.
Applying Polyurethane Over Different Paint Surfaces
You can apply polyurethane paint over different paint surfaces. The paint layer generally doesn’t require much protection, however applying an additional coating of polyurethane is a good idea. Let us consider how to apply polyurethane on different paint surfaces.
1. Applying Polyurethane Over Latex Paint
Applying polyurethane over latex paint is a very good idea. Latex paints are water-based and their cost is also economical. Water-based polyurethanes can be used easily on latex paint for additional protection.
2. Applying 0ver Acrylic Paint
Acrylic paints are water-based paints and after it dries, they will leave the surface exceptionally water resistant and durable.
You can apply polyurethane as layers, without disturbing the underlying acrylic paint layer. You should use water-based polyurethane when you are using it over acrylic paints.
3. Applying Polyurethane Over Enamel Paint
Enamel paints are mainly oil-based and are great for use on home exteriors. They can be of great use in indoor zones such as floors, kitchen, bathroom cabinets, etc.
Enamel paints are very glossy, compared with acrylic paint. Over this layer, polys have a hard time adhering. But enamel paints do not require polyurethane coating, as they are durable on their own.
Frequently Asked Questions [FAQs]
Q1. Can we apply polyurethane over concrete floors that are painted?
A1. You can apply polyurethane over concrete floors, that are painted. But painted concrete floors are not durable and might chip quickly.
Q2. Can I apply polyurethane over cabinets that are painted?
A2. Yes, you can apply a coating of polyurethane over painted cabinets. Though polyurethane is an ideal option for painted cabinets, there are other finishes available for cabinets, such as lacquer. Lacquer will last for years and it is also super smooth.
Q3. What are the advantages of spraying polyurethane over a painted surface?
A3. Polyurethane adds a layer of protection over paint and protects it from UV damage and weathering. It is possible to apply different colors of polyurethane over painted surfaces. The surface becomes resistant to scratching and general wear and tear. It also extends the time for repainting.
Q4. Can I apply polyurethane over chalk paint?
A4. Yes, we can apply polyurethane over chalk paint. But you have to make sure that chalk paint is cured completely before being layered with polyurethane. Chalk paint has a curing time of 21 to 30 days.
Q5. Will polyurethane adhere to all the surfaces?
A5. Polyurethane will generally adhere to all surfaces, but we have to make sure that the surface is clean and dry. The surface should also be free from wax, grease, and of course dust.
Q6. What type of polyurethane should we use?
A6. There are two types of polyurethane paint available. They are water-based and oil-based paints. The oil-based polyurethane will have a stronger finish and are capable of withstanding heat better. Oil-based paint will render a slight yellow hue on the surface.
Applying a single or a few layers of polyurethane over a painted surface is the best way to protect the paint. If you are very particular about the color of the finish, then you should make use of water based polyurethane over paint, rather than an oil-based finish. It is possible to apply the polyurethane layer on any type of paint, as long as the surface is clean and has been cured appropriately.
We hope we answered your question can I put polyurethane over paint in this article. We’d love to hear your experiences in the comments below.
Travis is a painter by profession. His valuable painting tips help customers know how to do painting hassle-free. He is an expert in handling painting tools and loves sharing his experiences with customers. Travis has been in the painting business for the past 20 years. He is now on the verge of early retirement, passing on the secrets.