Category: Oil or water based polyurethane over epoxy

Polyurethane varnish is one of the best finishes for a countertop -- it's durable and, when applied properly, can be just as subtle as lacquer. Best of all, applying polyurethane doesn't require spray equipment and is a job you can easily do yourself. The difference between oil- and water-based polyurethane varnish has more to do with the solvent than it does with the resin.

Oil finishes tend to soak into the grain and yellow. Varnishes all consist of resins, some of which have been modified with drying oils, dissolved in a solvent. They dry in two stages. During the first stage, the solvent evaporates, leaving a film coating on the wood, and during the second stage, the film cures -- usually by combining with moisture in the air -- to become hard.

The film in traditional varnish is usually provided by plant-based alkyds combined with linseed or tung oil.

oil or water based polyurethane over epoxy

Polyurethane is a synthetic plastic that replaces plant alkyds. It readily dissolves in organic solvents and, when emulsified with other chemicals, in water. After the solvent has evaporated, the plastic coating left behind by both oil- and water-based polyurethane products is the same, so durability of the finish isn't an issue. The main difference between water- and oil-based products is the appearance of the finish. The organic solvents in oil-based products soak the wood grain, so the varnish penetrates deeply, whereas water-based products tend to remain on the surface.

The result is that an oil-based finish tends to darken the wood and produce a deeper finish. Organic solvents also cloud with age, so an oil-based finish tends to yellow, while a water-based one doesn't. The best way to apply polyurethane varnish to a countertop is with a paintbrush, although the type of brush you need differs according to the solvent. Natural bristles are best for oil-based products, but because such bristles swell in contact with water, synthetic bristles are best for water-based products.

When finishing a flat surface such as a countertop, several thin coats are better than one or two thick ones. Thin coats allow the finish to mold itself around the contours of the wood grain, thus avoiding the plasticlike sheen often associated with polyurethane -- especially the water-based variety.

Water-based polyurethane has two important advantages over the oil-based variety. The first is that it's virtually free of volatile organic compounds, although the isocyanates in most formulations can irritate sensitive individuals. The second advantage is that water-based products dry quickly, allowing you to apply several coats in a single day.

One of the main disadvantages of water-based polyurethane is its tendency to form bubbles as you're brushing it. You can temper this to some degree by moving the brush slowly to reduce turbulence, and when bubbles form, it's usually easy to brush them out.

If they harden, however, the only way to get rid of them is to sand them. Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Woodworking Stack Exchange is a question and answer site for professional and amateur woodworkers. It only takes a minute to sign up. I recently finished a dresser top in a very light gray oil based stain. Afterwards I applied a water based matte poly, because I didn't want any yellow tint to show on the light gray color see this question. Should I have used a different combination?

So far so good, but am I likely to have problems with poly adhesion in the future because I mismatched the base types of the stain and poly? This should be ok if you gave the stain days to properly dry out. You'll want the oil-based drying agent to completely vaporize from the stain before applying the water-based finish. Please see this forum thread.

To quote from a Minwax representative:. Please use the following guidelines:. Once the stain color is set and cured passed the color-fast testapply 3 coats of the Minwax Water Based Polyurethane per label directions. Longer answer: if you wait for the oil-based stain to properly 'dry' cure it's no longer oily. This is because the curing process for oil is polymerisation, and polymerised oil is akin to resin.

Obviously the time between stain and varnish application will be a factor. But if you didn't experience major problems with beading of the waterbased poly as you were applying it I think you're OK. If you want to take an extra precaution you can use shellac as an intermediate coat. This can also be used to speed up the process because the shellac can go directly onto oiled wood without waiting for the oil to dry.

Then you can overcoat the shellac with your final finish after just waiting for the shellac to dry enough, perhaps as little as an hour.Why don't fictional characters say "goodbye" when they hang up a phone? If we can't tunnel through the Earth, how do we know what's at its center? All Rights Reserved. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply.

Polycrylic! Is it worth it!!?!?!

Hottest Questions. Previously Viewed. Unanswered Questions. Painting and Staining. Wiki User Nothing sticks to poly or gloss. You can paint over and stick all sorts of other applications to polyurethane with the proper preparation. You are wrong. With the proper preparation [scuff with 60 or 40 grit], polyester and epoxy resins will stick!

Yes, you can paint epoxy over polyurethane. Yes, polyurethane can be applied over epoxy. Asked in Wood Crafts Can epoxy and polyurethane be mix? Epoxy and polyurethane can be mixed. An epoxy and polyurethane coating system is often used in the marine industry to protect against the weather. Asked in Painting and Staining Can you use an epoxy over polyurethene? Yes, you can on some one-part epoxies; however, be sure to check the data sheet for the epoxy.

How to Polyurethane Over Water Based Paint

Most solvent based epoxies will act as a remover when placed over polyurethane. Polyurethane isn't epoxy, but they're both resins.The appeal of well-maintained, varnished wood trim on boats is hard to deny.

It evokes our past and we respect the owner because of all the time and effort it takes to apply and maintain the varnish. This required a period of weeks because only one coat of varnish could be applied per day. Each coat had to be sanded before the next coat could be applied.

Applying more than one coat per day caused the varnish to dry slowly, and in some cases to alligator and wrinkle. Varnish manufacturers now formulate products that speed up the process by allowing recoating the same day. While this reduces the total days required, applying all the layers still takes a great deal of time. When varnish is used alone as a coating, it is constantly fighting two distinct battles.

One is to stay attached to a substrate that is expanding and shrinking as the moisture content of the wood changes. Seasonal changes in moisture content occur because varnish is not a particularly effective moisture barrier. When the wood changes dimensions, it forces the varnish to stretch and shrink in order to stay attached.

Three coats of epoxy followed by three coats of varnish can achieve the same depth and look of twelve or more coats of varnish. More importantly, sealing wood with an epoxy moisture barrier dramatically lessens its stretching and shrinking.

Varnish benefits from being applied over a stable substrate. High-quality marine varnish is formulated with UV filters. So, the epoxy coating benefits by getting the protection from UV radiation that it needs.

The two in combination last longer than each coating by itself. Two-part clear polyurethanes are known for superior UV resistance and scratch resistance compared to traditional varnishes, but they have shown mixed results when applied directly to wood.

Two to three coats of epoxy also provide a stable base for clear two-part polyurethane finishes. Applied over epoxy, they perform beautifully together and outlast either coating used by itself. In new construction or when existing trim is removed for refinishing, we recommend that you encapsulate the piece with two to three coats of epoxy on all sides prior to installation and prior to applying varnish. Three coats on surfaces that will be sanded. This seals the wood, effectively protecting it from water.

You can install the trim with commonly used bedding compounds or glue it in place with epoxy. To eliminate places where water can get in, coat all drilled installation and hardware attachment holes with epoxy just prior to running the screws in. Wood surfaces completely coated in epoxy and protected with varnish or two-part polyurethane clear exterior finishes significantly outlast traditionally applied and maintained varnishes. Many people refinish their wood trim in place by stripping the old finish, sanding and applying two to three coats of epoxy before applying varnish.

For this method to work, it is important that the bedding compound beneath the trim be in good shape so water does not find its way into the wood behind the coating.Polyurethane, a plastic-based resin, can be used in many different ways.

oil or water based polyurethane over epoxy

When used as paint or varnish, it can provide a hard, durable gloss that is resistant to water and different kinds of chemicals. It is also very easy to apply.

When clear, this type of resin is mostly used for woodwork and furniture. It basically has two kinds: water based vs.

oil or water based polyurethane over epoxy

Polyurethane paints and varnishes used to only be oil-based. However, it has been discovered in recent years that water-based polyurethane works just as well.

Oil-based polyurethane has a more distinct odor and takes a longer time to dry than water-based ones. Another downside of oil-based polyurethane is that if you decide to use brushes, you will have to take time to clean them with a thinner. On the other hand, oil-based polyurethane lasts longer and is also more durable than water-based ones. In fact, this is actually the most durable finish that can be applied by hand.

It is also easier to apply than water-based polyurethane and is one of the best options to use if you want your furniture to have a natural look. Oil-based polyurethane also tends to penetrate the surface of the wood, thus, wetting its cells and giving it a darker color.

This penetration can also make the surface of your furniture shinier. One good method of applying oil-based polyurethane is to use mineral spirits to thin the finish before wiping it on.

This will prevent your furniture from having a plastic look. Also make sure that not to over-brush or over-wipe so that brush marks can be prevented and so the finish will be smooth and level.

When used on furniture, make sure that it is completely dry before touching or moving it. Usually, you have to wait four to five hours before applying new coats and twelve hours after applying the last coat before you can actually use your furniture. Oil-based polyurethane only requires around two to three coats since it contains 45 to 50 percent of the solids that create the protective finish. Water-based polyurethane has all the benefits of the oil-based ones, but it dries a lot faster and the odor is not as distinct.

It also has a clear finish that has a lasting effect, although most of the time it is shorter than oil-based ones. The addition of urethane to water-based finishes makes it tougher and more resistant to scratches. The tools used to apply this kind of finish can also easily be cleaned by water instead of applying thinner.

Furthermore, it releases fewer harmful chemicals and their containers can be disposed of in regular trashcans instead of special ones for hazardous wastes. This makes it both safer for the environment and your health.

Because of this, water-based polyurethane can also be used around children. However, it is not as heat resistant as oil-based polyurethane. It is also harder to apply because it tends to run.

Some water-based finishes can also be damaged when exposed to water for long periods of time. Water-based polyurethane is also more expensive than oil-based ones, usually costing twice as much. Because most water-based polyurethane only contains 30 to 35 percent solids, the recommended number of coats for a nice finish is four. Application of additional coats may also be required every two years.

Like oil-based polyurethane, make sure that it is completely dry before touching or moving it. However, unlike the oil-based ones, the waiting time between coats is usually only about two hours. Both oil-based and water-based polyurethane are the most effective finishes that you can use if you want your furniture to have good protection and if you want to make their wood tougher. This also means that dust and other air particles are more prone to stick to it.

Water based vs.Why don't fictional characters say "goodbye" when they hang up a phone? If we can't tunnel through the Earth, how do we know what's at its center? All Rights Reserved. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply. Hottest Questions.

Previously Viewed. Unanswered Questions. Home Improvement. Painting and Staining. Wiki User Yes you can. You should always check for compatibility of products, but generally an epoxy coating can be top-coated. Yes, you can paint epoxy over polyurethane. Yes, polyurethane can be applied over epoxy.

Oil Based Polyurethane vs. Water Based Polyurethane

Asked in Wood Crafts Can epoxy and polyurethane be mix? Epoxy and polyurethane can be mixed. An epoxy and polyurethane coating system is often used in the marine industry to protect against the weather. Yes, you can put polyurethane paint over eggshell in latex or eggshell in oil. Asked in Painting and Staining, Chemistry Can you epoxy over polyurethane?

Nothing sticks to poly or gloss. You can paint over and stick all sorts of other applications to polyurethane with the proper preparation. You are wrong. With the proper preparation [scuff with 60 or 40 grit], polyester and epoxy resins will stick! Asked in Painting and Staining Can you use an epoxy over polyurethene? Yes, you can on some one-part epoxies; however, be sure to check the data sheet for the epoxy.Polyurethane varnish is one of the best finishes for a countertop -- it's durable and, when applied properly, can be just as subtle as lacquer.

Best of all, applying polyurethane doesn't require spray equipment and is a job you can easily do yourself. The difference between oil- and water-based polyurethane varnish has more to do with the solvent than it does with the resin.

Oil finishes tend to soak into the grain and yellow. Varnishes all consist of resins, some of which have been modified with drying oils, dissolved in a solvent. They dry in two stages. During the first stage, the solvent evaporates, leaving a film coating on the wood, and during the second stage, the film cures -- usually by combining with moisture in the air -- to become hard.

The film in traditional varnish is usually provided by plant-based alkyds combined with linseed or tung oil. Polyurethane is a synthetic plastic that replaces plant alkyds.

It readily dissolves in organic solvents and, when emulsified with other chemicals, in water. After the solvent has evaporated, the plastic coating left behind by both oil- and water-based polyurethane products is the same, so durability of the finish isn't an issue. The main difference between water- and oil-based products is the appearance of the finish. The organic solvents in oil-based products soak the wood grain, so the varnish penetrates deeply, whereas water-based products tend to remain on the surface.

The result is that an oil-based finish tends to darken the wood and produce a deeper finish. Organic solvents also cloud with age, so an oil-based finish tends to yellow, while a water-based one doesn't. The best way to apply polyurethane varnish to a countertop is with a paintbrush, although the type of brush you need differs according to the solvent. Natural bristles are best for oil-based products, but because such bristles swell in contact with water, synthetic bristles are best for water-based products.

When finishing a flat surface such as a countertop, several thin coats are better than one or two thick ones. Thin coats allow the finish to mold itself around the contours of the wood grain, thus avoiding the plasticlike sheen often associated with polyurethane -- especially the water-based variety.

Water-based polyurethane has two important advantages over the oil-based variety. The first is that it's virtually free of volatile organic compounds, although the isocyanates in most formulations can irritate sensitive individuals.

The second advantage is that water-based products dry quickly, allowing you to apply several coats in a single day. One of the main disadvantages of water-based polyurethane is its tendency to form bubbles as you're brushing it. You can temper this to some degree by moving the brush slowly to reduce turbulence, and when bubbles form, it's usually easy to brush them out.

If they harden, however, the only way to get rid of them is to sand them. Chris Deziel has a bachelor's degree in physics and a master's degree in humanities.

oil or water based polyurethane over epoxy

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