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Can You Put Polyurethane Over Epoxy Resin? (Explained)

Polyurethane is a kind of plastic material. This material is used for having some unique features of it. This material is durable, adjustable, strong, and stretchy. This synthetic material can be used as indifferent physical formations. But can you put them over epoxy resin? Let’s find out.

Can you put polyurethane over epoxy resin?

Epoxy resin is a kind of organic polymer glue. Epoxy resin is used to glue different things. On epoxy resin, both oil-based and water-based polyurethane can be used. But water-based polyurethane is better as oil-based polyurethane may stain the epoxy resin.

Polyurethane is a plastic-based coating used over different surfaces to protect the surface from erosion and scratches. Polyurethane is not made of organic materials but has a longer life than its competitors, such as varnishes, lacquers, etc.

Water-based polyurethane over epoxy resin:

Water-based polyurethane is used over the epoxy resin, as it doesn’t cause any stain over the epoxy resin. Generally, water-based polyurethane is used for any sort of woodworking. 

This water-based polyurethane is used over a hardwood floor most of the time.

Epoxy resin is basically an adhesive that combines two different things closer. Epoxy resin is used in different things, from wooden work to metalwork. These are used to attach plastics, primers and seal wooden floors or furniture.

Polyurethane is softer and flexible. On the other hand, epoxy resin is hard. So, epoxy resin gives a tough texture, while polyurethane provides the surface with a smooth, soft touch. There is no harm to use water-based polyurethane over epoxy resin.

Oil-based polyurethane over epoxy resin:

Oil-based polyurethane can stay longer time than regular water-based polyurethane. Oil-based polyurethane uses different types of petrol-based and mineral-based material to solute in it. The oil-based coating is cost-efficient, and it is durable. 

Moreover, it looks better than the water-based polyurethane coating.

After coating with epoxy resin, one can cover it with an oil-based polyurethane cover to finish it with a better look. After putting epoxy over a surface, the surface may not look smooth and shiny. 

An oil-based polyurethane cover will perfectly cover up the scratch and resist some newer scratches. The only downside of oil-based polyurethane is it might put an orangey hue over the surface. 

Make sure to put the oil-based polyurethane over a hardened and sealed epoxy resin. 

Why Apply Polyurethane Over Epoxy Resin?

The best thing to go over an epoxy resin must be water resilient. The best water-resistant product is plastic, which has so many forms. The epoxy resin itself works as a dust cover. Polyurethane is not necessary to put on an epoxy resin. 

It is just another layer to make the surface solid and beautiful. Moreover, polyurethane coating will keep the surface from additional scratches and UV rays.

Will polyurethane stick to epoxy?

Epoxy resin can keep moisture away from the woodworks. Epoxy resin has a firm consistency, and it will become hard after some time. It doesn’t seem necessary to have any coating over an epoxy resin coating. But to resist scratches, you need to coat the surface with polyurethane.

Polyurethane cures epoxy of scratches and gives protection from Ultra-Violet rays. Ultra-Violet rays can cause oxidation to the epoxy-coated area. When applying polyurethane over epoxy, ensure that the epoxy is dried correctly.

Moreover, if applied properly water-based polyurethane coating sticks with the epoxy. And water-based polyurethane is not as shiny as oil-based one. A water-based coating may not put any stain over the epoxy, but an oil-based one will put some hue over the surface.

How many coats of polyurethane should you apply over epoxy?

Polyurethane, a proper sealant, can cover epoxy without any problem. Polyurethane has shiny properties. It can eradicate the risk of UV contamination and other contaminations as it gives a shiny, water-resilient cover over any surface.

A good water-based polyurethane is as good as oil-based polyurethane. Oil-based polyurethane over epoxy will ensure the glaze for longer and is cost-efficient.

When applying polyurethane, more than one coating is required over the epoxy. But it requires fewer layers for oil-based polyurethane than the water-based one. Three to four layers of oil-based polyurethane coating are necessary to have a shiny, beautiful surface.

How to apply polyurethane over epoxy resin?

One should require a pair of long sleeves, appropriate plastic gloves, and a respirator. 

However, to apply polyurethane, you will need to have, brand new sandpapers, Brush, Distilled water, rubbing and polishing compounds, mineral spirits, oil or water-based polyurethane, and a polyurethane sprayer.

Specified Work Area:

A specified work area is needed. If the work area is in an open space, anyone can get inside the area at any time. People may have some breathing issues as the polyurethane may fly around. Dust can fly and fall on the sprayed or brushed area.

Smooth the Surface Using Sandpaper:

Use the 80 to 100 grit sandpaper initially, then finish with 220-grit sandpaper to make the surface perfect to put epoxy resin. After rubbing with sandpapers, make sure to keep all the dust out, so clean the area properly.

Apply Epoxy Resin Over the Surface:

Apply epoxy resin all over the surface and make sure that the resin is covered the surface evenly. And after applying the resin, rest the coated surface for a day to dry properly. And let it cure for a week before applying polyurethane.

Apply the Different Layers of Polyurethane:

When the surface is fully ready to be coated with polyurethane. Oil-based or water-based coat, make sure you coat it well. You can use different methods to cover the surface with polyurethane. 

Choose one method out of brushing, wiping, or spraying, and do what is best for you. And remember to coat the surface three to four times. Before that, make sure that the polyurethane is not too thick.

Polish It Properly:

Finish it with a proper polish. Polyurethane is shiny, but after the coating and rest for two days. Polish a final thin layer of polyurethane and let it shine for a longer time.

Can you use wipe-on poly over epoxy resin?

There are several methods to cover epoxy resin surfaces. The methods are brush-on, wipe, and spray-on to put polyurethane over epoxy resin. From them, you can use the wipe-on method too.

Use a clean, smooth cloth about the size of your hand. Then dip one of the sides to a polyurethane solution. Then take the dipped side and wipe it evenly throughout the workpiece surface. After the first coating, repeat the wiping session three to four times. 

Then if there are any extra drips or gaps on the surface. Put the workpiece to dry for a day.

Can you put epoxy resin over polyurethane?

Polyurethane can be appropriately used on the epoxy resin. But can you put epoxy resin over polyurethane? Let’s find out.

Water-based polyurethane:

The experts don’t suggest putting epoxy resin over water-based polyurethane coating. Epoxy resin can ruin the water-based polyurethane surface by causing it to crumble. 

Moreover, it is hard for the epoxy to stick with a water-based polyurethane, which will cause the epoxy to be pushed away from the surface.

Oil-based polyurethane:

It is not wise to put epoxies over polyurethane. Whether it is oil-based or water-based, putting epoxy over polyurethane will not be fruitful. Putting epoxy over oil-based polyurethane will not stick properly. 

For that reason, after a few months, the surface of epoxy resin will peel off.

What is the best finish for epoxy resin?

There are several finishes for epoxy resin. The four of them are here to discuss.

Thin Layer of Epoxy:

A thin layer of epoxy is used most of the time. In general, epoxy resin finish doesn’t need any other coating. Epoxy coating is highly water-resistant. So small spillover of water on a tabletop or counter will not ruin the whole place. 

Places where parties always take place need to cover their table or counter with epoxy resin coating.

Seal with Polyurethane:

Sealing with polyurethane is also a great choice. As polyurethane is shinier and can increase the durability of the surface. Polyurethane ensures UV protection and protection against scratch.

Sanding and Polishing:

After adjusting everything with epoxy resin, sanding and polishing may bring some life to the surface. Proper sanding will ensure the surface is smooth, and polishing will increase the surface glazing capacity.

Combining the Polyurethane and Polish:

A combination of polyurethane and polishing will make the surface beauty eye-catchy. It will not be required, but one can combine the procedure for aesthetics. This process is good to have a classic look.

Final thoughts

Polyurethane can easily be used over epoxy resin. Polyurethane is not toxic too. Oil-based epoxy resin is recommended as it is cost-efficient. On the other hand, the water-based poly has the same property as oil-based. Polyurethane increases the glaze and protects the surface from UV contamination.