A polyurethane coating is used to coat wood floors, countertops, tables, and interior wood surfaces. It is resistant to water, chemicals, abrasions, solvent, impact, and other kinds of damage making it great for wooden surfaces.
But, the question is, how many coats of polyurethane should you apply? Read on!
What Is Polyurethane Coating?
Polyurethane coating can be water-based or oil-based. Oil-based polyurethane can be found in the market longer than water-based polyurethane. Polyurethane resin is mixed with alkyd varnish for you to make the polyurethane coating that you will like.
Almost all available oil-based varnish in the market contains alkyd. Adding the proper amount of polyurethane varnish can create a more durable coating. The mixture becomes scratch-resistant, water-resistant, and heat-resistant.
Water-based polyurethane uses acrylic resin mixed with polyurethane varnish, instead of alkyd resin. Since its mix is different, it may also have a different effect on the surface and different resistance levels. Nevertheless, it provides multiple benefits if used for the right wooden surfaces.
Moreover, to get your desired result, you should also know the proper polyurethane coats. As a general rule of thumb, you should apply at least two coats of polyurethane.
If you are working on furniture or floors, you should apply at least three coats. You may even use spray paint for the wooden flooring. A water-based polyurethane could be applied for up four or five coats.
Differences Between Water-Based vs. Oil-Based Polyurethane Coating
Let’s see some more differences between water-based and oil-based polyurethane.
Water-Based Polyurethane Coating
Water-based poly does not have a very strong odor. It is good for your safety and for the environment as well. Water-based polyurethane dries faster than other types of poly since it gives thin coats. Generally, it dries for around 6 to 12 hours and the surface will be ready. It is half the time needed for oil-based polyurethane to dry.
However, water-based polyurethane is not as durable as oil-based polyurethane. It may cause a slight rise in the wood grain which will require more sanding in between the coats of polyurethane. Adding a sealant layer can also be helpful. Nevertheless, It is not prone to drip since it applies thinner coatings.
How Many Coats of Water-Based Polyurethane Coating Do I Need?
You need at least five to six coats of polyurethane to reach a smooth coating. Only apply three to four coats of water-based poly for a less durable surface. It will help you achieve a good finish, but will not be as smooth and clear as an oil-based finish.
Oil-Based Polyurethane Coating
Oil-based polyurethane coats are a great option to achieve a strong and long-lasting polyurethane finish on wooden surfaces. Once it has cured, it can resist all kinds of damage. It provides thick coats hence you will need to apply fewer coats.
Once it is dry, it can also add warmth to the wood with its amber-like hue. Oil-based stain provides a protective coat on a wooden surface with its slow-drying process. However, if you want your project to dry faster, applying oil-based polyurethane is not suitable for it.
Moreover, it has higher volatile organic compounds (VOC) levels , which means it has a stronger odor than water-based polyurethane. You should use oil-based polyurethane outdoors or in a well-ventilated area to prevent suffocation.
How Many Coats of Oil-Based Polyurethane Coating Do I Need?
Apply three to four coats of polyurethane if you need a glossy finish. You may need additional coats depending on how much surface drips or runs you see while you apply oil-based polyurethane.
Normally, two or three coatings are enough, but if you are achieving a level of glossiness, then you add a final coat.
Recommended Number of Coats of Top Polyurethane Products
The number of polyurethane coats depends on the brand and type of polyurethane. Polyurethane finish can come in three different types: water-based, oil-based, and water-based, oil-modified formulations.
Look at the table below to see the comparison between popular brands of polyurethane. You will also have an idea of where to best apply them and how much coatings they need.
|Product||Coats||Hours Between Coats||Surfaces|
|Minwax Fast Drying||2 to 3||4 to 6||Floors, cabinets, furniture|
|Minwax High-build||2||4 to 6||Tabletops|
|Minwax Stain-and-Poly Combo||2||6||Trim, cabinets, furniture|
|Minwax Wipe-On Poly||3||2 to 3||Carved or profiled surfaces|
|Minwax Polycrylic||3||2||Light-colored kinds of wood|
|Oil-based Spar urethane||3||4||Exterior doors, trim|
|Water-based oil-modified||3||2||Cabinets, doors, furniture|
|Water-based spar urethane||4||2||Furniture, doors, trim|
|MINWAX Fast Drying Polyurethane Clear Finish||2 to 3||2||Doors, cabinets, furniture, floors|
|VARATHANE Ultimate Polyurethane||3 to 4||2||Furniture, doors, cabinets, trim|
Is One Coat of Polyurethane Enough?
If you don’t know how many coats of polyurethane you need for your project, some manufacturers are creating an easier and quicker solution: one-coat polyurethane.
This is an increasingly popular alternative for traditional polyurethane formulas. The one-coat or triple thick coat poly is even thicker than oil-based polyurethane. However, one coat is a little difficult to apply on wooden surfaces.
Just one coat is not usually enough as it is not always possible to get an even finish with one application. You will also see brush marks after applying polyurethane initial coat. As a result, you will need to use fine-grit sandpaper and do a second coat to make it smoother.
Is Layering 4 Coats Too Much?
Generally, you only need to apply three coats of oil-based polyurethane. You can apply four or five coats of polyurethane for a hardwood floor, especially if there’s a lot of moisture or it is the main passageway.
Manufacturers usually recommend at least three coats, even for water-based polyurethane applications. Do not apply too many coats as it can damage the surface. Too many coats do not always mean better.
Layering Polyurethane on Different Surfaces
Different wood surfaces need different amounts of polyurethane. Applying multiple coats of polyurethane will make sure that a specific wooden surface you applied it to will be shiny and protected. Here are the different surfaces and the number of coats you need for each:
Coats of Polyurethane for Furniture
To achieve your desired results, apply at least two coats of polyurethane to furniture. If the furniture is used more often, apply at least three coats of oil-based polyurethane. For water-based polyurethane, apply at least five coats.
Coats of Polyurethane for Outdoor Furniture
You can apply three coats of water-based polyurethane for outdoor furniture. However, you should apply polyurethane with UV protection since it can be exposed to direct sunlight. Additionally, it should be labeled “for external use” to prevent chipping.
Coats of Polyurethane on Doors
An interior wooden surface can have up to five coats of water-based polyurethane. You may a spray or bristle brush on an even surface. Allow the first coat to dry before applying a second coat.
Coats of Polyurethane on Cabinets
To get a professional-looking polyurethane finish, apply a minimum of three or four coats on the cabinets. More coats can make a big difference in the appearance and finishing of your cabinet.
Coats of Polyurethane on Wood Countertops
For wood countertops, you need to apply two coats of polyurethane. If the surface is high-traffic, then a third coat is needed. If you are using water-based polyurethane, you can add more coats than two as it has a tendency of rising the wood grains.
Coats of Polyurethane on a Kitchen Table
You can use three coats of polyurethane on a kitchen table. Kitchen tables may experience harsh situations such as constant cutlery scratching, liquid spillage, and pot banging. Therefore, it needs more protection. If you use three coats, the finishing will be more long-lasting.
How Many Coats of Water-Based Polyurethane on Hardwood Floors
If you are using water-based polyurethane on hardwood floors, you should apply three to four coats of polyurethane. If you get the desired shine at the fourth coat, sanding polyurethane can help more. Afterwhich, you should apply another coat.
Coats of Polyurethane on Stairs
Stairs are always used, and therefore, it needs a strong application of polyurethane. You should apply three coats of polyurethane. If the stair is still not smooth, apply an additional coat.
Coats of Polyurethane on Guitars
To keep your guitar in good condition, you can also apply three or more coats. Other owners find it good to apply one coat. But if you are always using it for gigs or even at home, applying polyurethane in more than one coat is better to prevent brush marks.
How to Apply Polyurethane Coating: 6 Steps
Now that you have an idea of how many coats of polyurethane you need for various surfaces, here are the steps in applying polyurethane successfully:
Step #1: Prep the Surface
Make sure the surface is clean, sand it if necessary and free from moisture, dust, or other debris. Otherwise, it will form bumps and bubbles under the polyurethane.
Step #2: Stir the Formula
Polyurethane is usually prepared before it arrives. However, while sitting in the can, some compounds may be uneven. Make sure to stir everything gently to ensure it’s smooth. A long, clean stick is okay.
Step #3: Spread the Coat
You may use a foam brush or bristle brush to apply the light coats of polyurethane. The first coat should not be thinned out. Thinning polyurethane on the first coat will not allow it to hold properly. Only thin out the surface if it has been coated with polyurethane in the past.
Step #4: Allow the Surface to Dry
Give enough time for the polyurethane surface to dry. Some brands require 4 or more hours before the next coating. If you are using oil-based polyurethane, it will need more time to dry. Water-based polyurethane thin coat dries out faster.
Step #5: Sand the Surface
Once the first layer has dried, gently light grit sandpaper and begin sanding polyurethane surface. Remove wood dust and other dirt from the surface. You may use a soft cloth or dry cloth that is lint-free to do it.
Step #6: Apply the Second Coat
After cleaning the surface, you may now apply the next coat. The second coat can be the final coat as well, depending on your project. You may apply additional coats to remove brush marks lightly using single strokes.
Must-Know Tips and Tricks
Here are some useful tips and tricks to remember when adding polyurethane resin or the best oil-based polyurethane to a wooden surface.
1. Stir the traditional solvent-based polyurethanes instead of shaking them.
2. Use a foam brush or roller brush when applying the coating.
3. Apply a thin polyurethane coat to prevent a drip.
4. Thinning polyurethane can also help it to dry faster.
5. Do not thin out the poly’s first layer.
6. Use a high-end brush to prevent bubbles or brush marks.
7. Do not wipe the brush on the can’s edge to remove excess polyurethane, just tap it over the top of the container to prevent bubbles.
8. The brush strokes should be aligned with the wood grain to let the pores sip, giving you a smooth surface.
9. Soaking the brush in mineral spirits or water can help you cleanse the polyurethane brush easily.
10. Use fine-grit sandpaper to prevent awkward streaks on the final coat. Use as few brush strokes as possible.
11. Never apply another layer of polyurethane on previous coats that aren’t dry yet. Do not apply too many coats as well. Usually, a third coat would be enough for your project.
The Best Polyurethane in the Market Today
Here are three of the best polyurethane in the market:
#1: Best Water-Based: VARATHANE Polyurethane
Varathane offers a durable and smooth water-based polyurethane surface. It is stain and scratch-resistant, which is great for indoor use. It will not turn yellow and will leave you with a clear, semi-gloss finish.
#2: Best Oil-Based: MINWAX Fast-Drying Polyurethane
Minwax Fast-Drying Polyurethane provides a long-lasting finish. It will give a shiny and durable surface. You can use it over finished wood or bare wood for ultimate protection.
#3: Best Oil-Modified Water-Based: MINWAX Water-Based Oil-Modified Polyurethane
Minwax Oil-modified Water-based polyurethane can be used in any wooden surface inside your home. It is long-lasting and provides a glossy finish after the final layer. It dries up quickly and is easy to clean.
What is the difference between 2 vs. 3 coats of polyurethane?
The difference between 2 vs. 3 coats of polyurethane is the protection. Two coats are enough. However, you can go for three if you want extra moisture and contaminants protection.
How long should polyurethane dry between coats?
The time polyurethane should dry between coats is about 2 to 24 hours depending on the type you use. For water-based polyurethane, wait for 2 to 4 hours before applying the second coat. For oil-based polyurethane, you may wait for 10 to 24 hours before applying the next coat.
Is a 2-coat application of polyurethane enough?
2 coat applications of polyurethane are enough to give your wood protection against contaminants and moisture. However, if you want added protection, an additional coat can be good.
Can polyurethane be thinned?
Yes, polyurethane can be thinned using water, turpentine, paint thinner, or mineral spirits.
What is the best drying temperature for polyurethane?
The best drying temperature for polyurethane is between 70 to 77 degrees Fahrenheit. If the temperature is lower, it can take more time for the polyurethane to dry.
How do you get rid of air bubbles in polyurethane?
Sanding polyurethane with fine grit can help in smoothing out the bubbles. However, if the bubbles are very large, they may be hard to pop. Use a high-grit sanding sponge with 80 to 100 grit, wipe the surface with denatured alcohol, then repeat.
How do you remove brush marks on surfaces applied with polyurethane?
To eliminate brush marks on a wooden surface, let it dry for 24 hours and scuff sand it with 320 grit wet-dry paper. Mineral spirits can act as a lubricant to dry sand which can also be used to remove marks.
How many coats should I apply on stained wood?
Stained wood requires two thin coatings of polyurethane for long-lasting protection. It will also hide the wood’s imperfection and grain.
How many coats of wipe-on poly is enough?
Three coats of wipe-on polyurethane are enough to match the wood or buildup you are working on.
How are the different types of polyurethane thinned?
Oil-based poly should be thinned using mineral spirits. While water-based polyurethane can be thinned using water or lacquer.
Can I apply a second coat of polyurethane without sanding?
No, you can’t apply a second coat of poly without sanding it. You can use 120-150 grit sandpaper to sand the surface. It ensures that the polyurethane will hold on to the wood longer.
How many coats do you need on interior doors?
You can add up to five coats of poly to interior doors. You can spray or brush it evenly and let it dry before applying the next.
How many coats of Varathane polyurethane should I apply?
It is recommended to use a minimum of 3 coats. If wood grain rises, sand it before applying the next. Wait for 24 hours before using the surface and 3 days for fully functional usage.
How many coats are needed for pine walls?
You need to apply 2 coats to pine walls for protection. If the wall is prone to moisture, you may apply 3 or 4 coats.
How many coats are needed for butcher blocks?
Use 3 or more coats of Polyurethane on a butcher block, especially if you are doing an oil-based finish.
Knowing how many coats of polyurethane depends on the project and the type of polyurethane you use.
You may choose between oil-based, water-based, and oil-modified water-based in your projects. Generally, two or three coats will be enough for any kind of wood.
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