My New Favorite Water-Based Polyurethane Over Paint! (2024)

FAQs

Can you put water-based polyurethane over paint? ›

Yes, you can. As long as the oil-based paint is fully cured and you clean and scuff sand the paint surface, water-based polyurethane will adhere well.

The basic application technique for water-based poly is similar to that for oil-based. Apply a very thin coat of polyurethane with a fine brush, foam pad, or cloth. Work with the grain, and avoid applying too much polyurethane to avoid raising the grain.

Product Options. Polyurethane can be oil- or water-based, and you can use either kind over latex paint; however, oil-based polyurethane tends to yellow as it ages, whereas water-based varieties stay transparent.

Polyurethane is so durable and water-resistant, it has largely replaced shellac and varnish as a wood finish. Originally, it had to be brushed on, but different formulations mean it can now be applied as a spray or by wiping it on with a rag.

High quality water based polyurethanes is considered by many homeowners & flooring professionals to be equally durable. Oil based poly can last around 10 years. Water based poly can have the same longevity. The key is using high quality water based poly like Bona Traffic and having it applied by a professional.

Water-based polyurethanes are thinner liquids, which means that they will require four to five coats. Oil-based polyurethanes are thicker, and will need between three and four coats.

My last project was a simple pair of matching step-up stools for my kids. I learned alot about mortise and tenon and flattening boards by hand, but what stumped me was the finish. I used a water based Polyurethane and it dried so fast that you can see brush strokes in reflective light.

Water-based polyurethane requires at least two hours of dry time between coats, and you should only apply two coats in a day. It's important to remember that drying time is affected by temperature and humidity.

What is the main disadvantage of using water-based polyurethane? Water-based polyurethane can raise the grain of the wood and make it rough-looking. This happens because water-based polyurethane is absorbed into the wood, causing the grain to swell as it dries.

Vinegar should never be used on polyurethane floors, for example. Because it's an acid, vinegar can eat away at hard finishes like polyurethane and wax. Use only white vinegar, diluted with water, on soft floors that are finished with an oil-based coating.

Do you need to sand between coats of water based polyurethane? ›

Sanding between coats is not required for adhesion as long as the time between coats is less than 6 hours. However, screening or sanding between coats usually produces a smoother better looking finish. A minimum of 3 coats of finish are recommended. Do not apply more than two coats the same day.

Don't use rollers or foam brushes—they create bubbles. Your brush will be easier to clean, and will go longer between cleanings, if its bristles are dipped first in mineral spirits, if you're using an oil-based poly, or in water, if the finish is water-based.

The proper way to polyurethane over paint. Before you add a few polyurethane layers over dried paint, you'll need make a few preparations before you can get started. It's important to note that your paint should be fully cured before you apply a layer of polyurethane.

For fast-drying polyurethane and most water-based poly, it will still remain glossy even after sanding, so it won't necessarily help with adhesion. In conclusion, it's necessary to sand polyurethane between coats for a perfect finish.

Water based poly, an acrylic product, is a thinner, but harder coating. Oil poly can be more susceptible to dents, while water based poly can be more susceptible to surface scratching.

A roller is the recommended method for applying some water-based polyurethanes, as well as some oil-based polyurethanes and moisture-cured poly finishes.

Put on the polish

Apply only one thin coat. Then, remove any dust nibs with 1,500-grit sandpaper or a piece of brown paper bag. Finally, using a soft cotton rag or polishing pad, buff the finish to a high shine using automotive paste wax, photo below, which has fine abrasives that polish the finish even further.

You'll want to use water-based polyurethane if you have any aversion to dealing with messy, odorous solvents. Water-based polyurethane finishes are easy to apply and easy to clean up after. If you only need a thinner, more flexible coating, water-based polyurethanes might be right for you.

You are best off using 3 coats of water based polyurethane for the best results. And, this is is especially important on the 1st floor of your home and heavy traffic areas (e.g. kitchen, entryway, family room).

Can you sleep in house after water based polyurethane? ›

We recommend a minimum of 2 days of socks-only traffic for floors finished with oil polyurethane. The house is not inhabitable for a minimum of 2 days after the job is completed, and better to stay out for at least 5 as the fumes/off-gassing is not advisable to breathe in, even if there are other rooms to sleep in.

An oil based polyurethane will continue to amber and darken over time, while water-based poly will remain clear for the lifetime of the hardwood floor.

Always allow polyurethane to dry 24 to 48 hours before sanding, to give the surface time to cure and harden.

Thin your polyurethane with paint thinner, mixing it with a paint stir stick. When polyurethane is too thick, the brush marks hold their shape and don't settle out. Thinning the product provides a smoother finished surface. Experiment with different amounts of paint thinner to see what works best for you.

Synthetic bristle brushes are the most common option. The bristles are made with synthetic material, like nylon or polyester, which is better for applying water-based polyurethane. These brushes are also frequently used with latex-based paints.

Tip: Before use, a can of polyurethane should be stirred, not shaken. Shaking can introduce air bubbles in the finish that could make an uneven coat.

Can you apply polyurethane with a foam roller. Yes, you can apply more polyurethane with a foam roller, microfiber, and mohair. The foam works well with oil-based poly. However, don't use a foam roller when applying water-based polyurethane.

What happens if you don't sand between coats. If you fail to sand polyurethane that requires it, you will compromise the adhesion between the coats. Instead of the coats combining, each dries independently, creating layers.

You should normally use between two and four coats of polyurethane; however, a lot depends on whether the polyurethane is water-based or oil-based.

Oil based polyurethane lasts longer than water based.

There is no contest on the durability between the 2 options. Water based polyurethane has lower VOC's - which is a bit of an environmental benefit (more about that in a moment) - but because it has lower VOC's (Volatile Organic Compounds), it doesn't last as long.

Can polyurethane damage your lungs? ›

► Urethane is a PROBABLE CARCINOGEN in humans. There is evidence that it causes lung, liver, blood, and other cancers in animals. a carcinogen.

Overall, it is said that it takes a full 30 days for the floors to properly cure, which means this will likely be the duration of time that you deal with toxic fumes in the air space.

Most standard cleaning solutions contain either an alcohol or ammonia base, which over an extended period of time, can eat through the finish. At Grain Designs we also use low sheen urethane finishes. Common furniture cleaners such as Pledge furniture polish, may actually damage the topcoat of your furniture.

Use a smooth piece of sandpaper that's around 1500-grit, then start rubbing down the finish in long, smooth motions. If you don't have any sandpaper on hand, you can also use a brown paper bag to buff the surface. If you don't have any super-fine sandpaper on hand, you can use a lower grit level, like 320.

Thin your polyurethane with mineral spirits.

The mineral spirits will provide a more forgiving coat of polyurethane and will also help any bubbles in the finish to burst before it sets up and dries. Pour the polyurethane into a separate container and add some mineral spirits.

When you recoat after 2 hours you get a chemical bond between layers. If you let it go longer than that, you need to wait 24 hours so it's hard enough to sand and get a mechanical bond.

Sand lightly with 240-grit sandpaper between coats, then let the last coat dry for at least 24 hours. This is standard practice with any wood finishing job, and is nothing out of the ordinary.

The All-Around Best Clear Coat For Painted Wood Furniture: Varathane Water-Based Polyurethane, Satin. After testing seven different products, Varathane's Water-Based Polyurethane was the clear winner! This clear coat is great for interior products including furniture, cabinets, trim, or any other pieces of wood.

Applying a Water-Based Polyurethane

Apply a very thin coat of polyurethane with a fine brush, foam pad, or cloth. Work with the grain, and avoid applying too much polyurethane to avoid raising the grain. The initial coat should be dry within a couple of hours, and you can then apply a second coat.

Does polyurethane stop paint from peeling? ›

Polyurethane is a clear varnish that dries to a hard, solid finish. It protects your wooden surfaces from scratches and prevents paint from peeling, and it's easy to clean.

To avoid bubbles in water-based polyurethane, apply multiple thin coats using a quality synthetic polyurethane brush instead of a natural brush. And before applying polyurethane, dampen the brush with water to avoid bubbling, puddling, or running.

Yes, you can varnish over emulsion paint. However, it is recommended to apply water-based varnish over emulsion paints because most of these paints contain a high volume of water as the paint thinner. So the paint might not be compatible with oil-based paint.

Can Polycrylic^® Protective Finish be used over paint and wall coverings? Yes. Polycrylic^® may be applied over latex and oil-based paints and well-bonded wall coverings. Because slight ambering may occur, spot test on an inconspicuous area and let dry to ensure satisfactory results.

Can Water Seal be applied to painted surfaces? No. Water Seal can only be used on bare and uncoated brick, stone or concrete.

It's best to use a brush with natural rather than synthetic bristles for oil-based finishes, and synthetic brushes (often called 'nylon' brushes) for acrylic or water-based varnishes. But you can also use rollers or rags for both kinds of finish.

The All-Around Best Clear Coat For Painted Wood Furniture: Varathane Water-Based Polyurethane, Satin. After testing seven different products, Varathane's Water-Based Polyurethane was the clear winner! This clear coat is great for interior products including furniture, cabinets, trim, or any other pieces of wood.

21 days for water-based products. 30 days for oil-based products. You can use a piece lightly after about 7 days but be cautious - the finish will still be curing for another 2 or 3 weeks.

Put on the polish

Apply only one thin coat. Then, remove any dust nibs with 1,500-grit sandpaper or a piece of brown paper bag. Finally, using a soft cotton rag or polishing pad, buff the finish to a high shine using automotive paste wax, photo below, which has fine abrasives that polish the finish even further.

Apply the first coat of polyurethane using the best technique for the surface. Brush flat surfaces with a thin coat using a bristle brush. Wipe contoured surfaces with a clean cloth, going with the grain. Brushing a rounded, contoured or vertical surface is more likely to create drips.

Which is better polycrylic or water-based polyurethane? ›

Polyurethane is better for durability, but polycrylic is better for interior surfaces like cabinets, furniture, and trim. However, for light painted furniture and cabinets, polycyrlic is preferred because it doesn't yellow on the surface.

Water-based polyurethane contains dries faster and is safer to use because it gives off fewer fumes when you are using it. Polycrylic is water-based and less toxic than polyurethane options.

Water-based polyurethanes lack that amber cast, but some still do cause white or light-colored surfaces to yellow after drying or become slightly cloudy over darker finishes such as milk paint.

Varnishing helps protect your painting by putting a sealing layer over your work. This means that if you varnish a painting and then put it outside or near water, you don't have to worry about it being damaged.

Adding a Second Coat

After your first coat of paint is dry, it's safe to recoat typically after four to six hours. A good rule of thumb is to wait at least three hours to recoat your paint or primer if it's water-based. Waiting 24 hours is best for oil-based paint and primer.