Can You Put Epoxy Resin Over Varnish? Simple Tips to Using Epoxy Resin

Image of epoxy table but Can You Put Epoxy Resin Over Varnish?Using varnish on wood dates back to the early woodworkers who used natural resins such as plant secretions. The product is used up to date since it provides protective coatings for paintings, wooden surfaces, and many more decorative objects. Epoxy resin is another ideal product with high strength and durability for your wood. But you need to ask yourself, Can You Put Epoxy Resin Over Varnish?

It’s recommended not to apply epoxy resin over other coatings. Doing this will cause damage to the epoxy layer. But if you insist on trying it out, don’t use any other solvent apart from thoroughly dried water based stain.

It’s good to note that if you apply the epoxy resin over varnish, it may cause it to soften. Besides, never expect a varnish like finish if you use epoxy resin.

How Many Coats of Epoxy Resin Over Varnish?

If you apply varnish over epoxy, it’s recommended to use about two to three coats of epoxy resin to protect the wood from water. Contrary, you’ll only need one coat or at most two coats of epoxy resin when applying it over varnish. 

The varnish has excellent waterproofing properties. Hence a single coat of epoxy over it will still keep the water away from the wood.

How Long Does Epoxy Resin Take to Dry?

Epoxy resin will take around 72 hours to dry thoroughly. Even so, this drying period varies depending on the specific resin. Altogether, ensure that you give the resin enough time to dry before taking any other action on it. 

Suppose you don’t let the surface fully dry. You’ll be risking surface contamination for your project. 

What Is the Fastest Way to Cure Epoxy Resin?

72 hours may look so long to wait for your epoxy resin to dry. Also, remember that this period will vary depending on your application methods and the weather conditions. 

If you follow the below steps, you’ll never have to worry about long drying periods anymore. 

  • Buy a faster curing resin- Each of these products has a specific description of the curing time from the manufacture. When purchasing, ensure you choose a faster curing resin. Doing this will help speed up the drying process.

With a fast drying agent in their formulation, such resins always start drying a few minutes later after pouring. Therefore, if you are a fast time user, this method is not recommended for you. 

The reason is that it reduces the adequate time you would have used to work with your resin correctly. Due to this, you will face a challenge evading small mistakes.

  • Prewarm your materials- Suppose you didn’t get a fast drying resin. You can choose to warm your materials before applying. Doing this is as easy as placing the bottles of resins in hot to touch the water then allowing them to settle for at least five to ten minutes.

Alternatively, you can consider using machines such as heat guns or hair dryers to blow warm air on the resin immediately after pouring. Even so, ensure you apply moderate heat and use the machines evenly over the surface.

It will help if you be very keen on bubbles and crackings.

  • Increase room temperature- If you increase the temperature of your room, you rest assured of a fast drying time. You can do this by bumping up your thermostat or adding an extra heat lamp in the room.
  • Use UV resin- Do you want the fastest way to cure your epoxy resin? Then it would be best if you went for UV resin. The product takes as little as 2 minutes to get cured. But this should be under a UV lamp. 

Being a specialized resin, you cannot cast this product into thick layers.

What You Shouldn’t Do to Speed up Epoxy Resin Cure

  • Don’t use too much color. It’s recommended you use not more than 7%.
  • Avoid mixing many materials. For this case, don’t use a curing agent that did not come with the resin. It will prevent the mixture from curing.
  • Don’t use too much curing agent. If you use an excess curing agent, it might cause the resin to harden even as you pour.
  • Use the recommended quantity as per your manufacturer.

Do I Need to Sand Varnish Before Applying Epoxy Resin?

Sanding is one of the best ways of surface preparation. Even though the epoxy resin is highly adhesive and can stick to most surfaces easily, lightly sanding the varnish surface will strengthen the bond.

Final Epoxy Surface Preparation

Preparing your surface before applying the epoxy resin will ensure that your resin is well protected from damaging UV rays. Besides, it adds beauty to the final finish.

Mostly, you’ll use finishes such as paints or varnishes for the epoxy surface. Not forgetting that such finishes require proper epoxy surface preparation.

Here are the four main steps that you will use.

  • Step 1

Ensure that the final coat has thoroughly dried.

  • Step 2

Before drying the surface with paper towels, take some time and thoroughly wash it with water and scotch brite.

  • Step 3: Sand to a smooth finish

Gently sand with 80 grit sandpaper to eliminate any sags or rags, especially on the highest areas. Do this until you are satisfied that the surface feels and looks fair.

According to the coating instructions, sand with the appropriate sandpaper depending on the type of coating you want to use. You should note that your paint will adhere to the surface depending on its mechanical grip on the surfaces facilitated by the final sanding.

80-100 grit is ideal if you plan on coating the surface with a high build or filling primer. However, if you prefer primers and high solids coatings, go for 120-180 grit sandpaper. Finally, consider finishing with grits between 220-400 since finer grits than this will not result in enough mechanical grip for your paint or varnish.

Tip: You can choose to use wet sanding since it will reduce the sanding dust. Doing this will also make step 2 not necessary.

  • Step 4

After sanding, thoroughly rinse the surface with fresh water.

Note: If the cleaning water bends or forms a fishing eye at any point on the surface, that point is not even. Wipe and dry the specific area, then wet sand to eliminate the contamination.

Do you want to prevent any chances of contamination to the epoxy surface before applying the final coating? Then, ensure you coat within 24 hours of the final sanding.

Can You Apply Epoxy With a Brush?

Yes, you can use a brush to apply epoxy resin. However, I suggest you use a bristle brush or a nap roller for the best results. If you prefer sanding before application, go for a chip brush. 

The only drawback is that bristle brushes can result in uneven application. Such will happen when the bristles get weighed down with the product. In such a scenario, you’ll require more sanding before the next application.

For the best results, consider using a foam roller brush. 

What Is the Difference Between Varnish and Lacquer?

Even though both varnish and lacquer are durable and dependable, they have some distinguishing factors.

Let’s check on some of their differences.

What Is Varnish?

Varnish is a hard, transparent, protective finish that you can use to protect your wood. Also, this product is helpful for top coating or finishing while maintaining the wood’s natural beauty. 

Don’t forget that it’s durable and protects the wood’s surface from UV rays since it has a higher solids ratio.

Varnishes are essential in woodworking since they always highlight the natural beauty of different wood types.

What Is Lacquer?

Unlike varnish, which is transparent, lacquer comes in different colors and degrees of opacity. Even so, it leaves a hard glossy finish as varnish does. 

The unique thing about lacquer is that it’s tough enough to withstand acid base corrosion.

The Main Differences Between Varnish and Lacquer

  • Sheen level

Lacquer provides a range of sheen levels from high gloss to ultra matte. On the other hand, varnishes have a semi gloss or satin sheen finish.

  • Durability

Both of these products are durable. However, lacquer is highly resistant to corrosive solvents than varnish.

  • Method of application

When applying these products, you’ll mostly use a similar application method. For varnish, you’ll have to brush at a relatively slower speed. On the other hand, lacquer is easy to spray hence the fastest to dry.

You’ll have to be more precise when applying varnishes, but this will result in high quality wood shine.

  • Flammability

Do you know why you’ll mostly apply lacquer far away from home? The reason is that it’s flammable than varnish.

You can apply lacquer onsite, but you must be ready for some little mess.

Can I Use Lacquer over Varnish?

I don’t recommend doing this. Instead, apply shellac between the two.

Can I Stain Epoxy?

Yes, you can stain epoxy. However, some factors determine how the bond will be. In some cases, the epoxy will take quite long to dry than in others. The stain type also determines the bonding time of the two products.

Does Stain Ruin Epoxy?

You’ll have to use water or alcohol based stains for the best results. If you go for oil based stains, the epoxy will not bond and seal properly to the surface. 

Should I Stain Before or After Epoxy?

It’s right to apply the epoxy before staining the surface. However, since you’ll have to sand the dried epoxy, it’s good not to start with staining as you might accidentally sand through some of the stains.

What Is the Difference Between Varnish and Polyurethane?

You can use either of these products as finishes, but this doesn’t mean that they are similar. Let’s look at some of their differences.

As seen before, varnish has a higher amount of solids to give the wood a tinted color after application. On the other hand, polyurethane can quickly harden since it has a liquid plastic formulation.

Polyurethane can be either water or oil based. DIYers prefer using the water based one since it’s easy to apply. The oil based polyurethane offers more protection to the wood but comes with some disadvantages such as long drying time and toxicity.

  • Uses

You’ll mostly use polyurethane for bookcases, picture frames, hardwoods, desks, and wood flooring. In contrast, the varnish is ideal for softwoods, boats, outdoor decks, and deck chairs.

  • Durability

Even though polyurethane is very durable, it can suffer some cracking and UV damage. Varnishes are less durable, but they offer better protection against UV damage. They are also more flexible.

  • Toxicity

The water based polyurethane is less toxic than oil based. But, in contrast, the varnish is less toxic than both water and oil based polyurethane.

What Is the Difference Between Epoxy and Polyurethane?

Let’s start by looking at what epoxy is and why you need it for your wooden structures.

Epoxy mainly consists of a resin and a curing agent. When the two formulations combine under chemical reactions, they form a hard rigid substance (the process releases heat).

Uses of Epoxy In Woodworking

  • Repair agent- You can use this product to repair rotting or damaged wood. The best part is that the final product will be of no match difference in strength as the original wood.
  • Coating or sealant- Another everyday use of epoxy is a coating or sealant for creating floorings and countertops. This item is more efficient, especially in areas where hard wearing isn’t a major concern.
  • Adhesive- The unique thing about this product is how it can adhere to almost all surfaces. Therefore, you can use it as an adhesive for many woodworking jobs.
  • Paint- Even though you can use this product as paint, it’s only ideal for metals, not wood.

Uses of Polyurethane In Woodworking

Polyurethane has a formulation of two significant compounds, including resin and a hardener. What’s best about this product is how you can determine the ratio of the compound to the hardener. 

Here are Some of Its Primary Uses.

  • Adhesive- Unlike epoxy that can bond with almost all materials, polyurethane bonds with fiber, wood, leather, among others. The bond is always strong and has a clear appearance.
  • Abrasion resistant coating- One of the main benefits of this product is how it can absorb impacts and ward off scratches.
  • Filler- You won’t use polyurethane to strengthen woods as for epoxy. Instead, you can use it to fill cavities and other spaces on wood.
  • Varnish style coating- Apart from the above uses, you can use this product to create coatings for other materials. The reason is that it forms a clear finish, thus highlighting the wood’s natural beauty. 

Other Differences

  • Durability

Epoxy has a more robust and durable bond than polyurethane. The product can also withstand extreme levels of compression strength. Therefore, you can use epoxy on surfaces you are most likely to put heavy weight objects.

  • Chemical resistance

For this case, epoxy is again better than polyurethane in chemical resistance. But, polyurethane can resist solvents and alkalis.

  • Resistance to humidity and moisture

Here, you’ll realize that epoxy is more resistant to humidity and moisture. In contrast, polyurethane can resist high temperatures thanks to its flexible coating that prevents it from breaking or being brittle in extreme temperatures.

  • Resistance to scratching

Between the two products, polyurethane finish is more resistant to scratches than epoxy. 

Can You Put Epoxy over Epoxy?

Yes, you can put epoxy over epoxy but ensure you follow the correct steps for the best results. You can add the second coat after the first one gets tacky (roughly between 4 to 6 hours). 

What if you delay and the first coat cures? Here, you’ll have to sand the surface before applying the next coat.

Can You Sand Epoxy?

As explained above, you can sand epoxy, especially when you want to add a second layer. Light sanding the surface can also give it a less glossy appearance.

I suggest using 320 grit sandpaper to lightly sand before applying the second coat after your surface has thoroughly dried.

Suppose the surface is still tacky after 12hours. It’s a clear indication that you didn’t have the correct ratio of the hardener and the resin. The other reason is that you might not have thoroughly mixed the compounds.

You’ll want to wipe off the tacky areas, then sand down the areas and reapply the epoxy in such cases. If you don’t do this, you’ll be risking an uncured surface for the other layers.

Final Thoughts

If you have reached this point of the article, you have seen how epoxy and resin play an essential part in woodworking. What’s best about epoxy is how you can use it on most wood surfaces. For varnishes, they have excellent waterproofing properties. Therefore, when used on the wood, you rest assured of durability and strength. But…

Can You Put Epoxy Resin Over Varnish?

Yes, you can put epoxy resin over varnish. However, it’s not recommended to use oil based varnishes if you intend on adding an epoxy layer on top.

Thank you for reading this article. If you still have more questions or observations on the related topic, kindly reach out in the comment section below.

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Tyron Otieno

Tyron is an avid woodworker and writer. He founded this website to help other woodworkers, whether hobbyists or professionals by sharing his knowledge and experiencie after a decade of woodworking.