Filling Large Voids in Wood with Epoxy 2022 – Guide

Are you struggling with the correct way to Filling Large Voids in Wood with Epoxy? Do you want to know the proper way to prepare your large voids for later filling with epoxy? Please read the article below to give you a detailed step by step (with no step skipped) process on how to fill large voids or cracks in wood with epoxy.

On occasion, as a woodworking enthusiast, you are bound to land on wood pieces that have large voids, cracks, or holes in them. Although the large voids are not easy to work with, especially when you want the smoothest of surfaces, it is aesthetically pleasing to view these ‘defects.’
Therefore, instead of using substances like wood putty that would not maintain the look of the large voids, cracks, or holes, it is more beneficial to use epoxy resin to fill cracks in wood or, generally, the use of epoxy for wood repair. Epoxy results are beautiful and intriguing, increasing the engagement of surface users with the newly epoxy surfaces.
Read the following steps to ensure you end up with aesthetically pleasing epoxy surfaces that leave you or other surface users excitingly engaged and hard-pressed to touch the crack, hole, or void.


The very first step in filling wood cracks with resin is to clean all of the inclusions on the inside of the large voids in the wood.
Then, remove all the loose debris you could be having to reduce the degree of potential bubbling that could negatively affect the final results’ aesthetics. Some of the debris will be punky wood that rots or already pilling bark.
If the bark is peeled, it is beneficial to use a wire brush along the grain to improve the aesthetics of the woodworking surface. However, if you want to eliminate as much debris, then it is advisable to use the wire brush against the grain.
Although going against the grain reveals interesting textures and colors, it is important to push a brush or two along the grain to maintain the natural look and feel of the large void that you want to fill with epoxy resin.
Always remember that the reason you are using epoxy in the first place is to reveal some detail beneath your surface, and as such, you ought to make the details as interesting as possible.
Next, you should source a finer brush to the likes of a toothbrush that is meant to get rid of any small debris that could be hanging on a face in the large void.
A chisel should be used if you want to eliminate a particular wood piece of craft and art. Note that the cleaning and brushing exercise should be done on the top and bottom side to ensure no debris floats on the epoxy, reducing overall craftsmanship.


To start, flip the voided wood piece over to access its bottom side. Find any of the knot holes, cracks, or voids that show to this bottom side and tape them off.
Taping these voids on the bottom side allows the epoxy to avoid leaking that would otherwise cause sunken epoxy surfaces or mess the workshop floor surface. It is crucial to tape all of the bottom voids regardless of their size since it could be leading to a big crack on the top side.
You want your tape to be a wrestling mat tape that is quite flexible and holds on to the surface phenomenally well as to require significant pressure.
This feature is very well suited for the huge pressure on the bottom by the high amount of epoxy needed to fill large voids in the wood.
When it comes to filling large voids in wood with epoxy, it’s not a worthwhile adventure to run a series of tape wrap across the bottom of the void. This way, one ends up creating many planes of weakness through which the epoxy could leak.
Also, due to the stickiness of the adhesive, the sticky part is bound to catch dust and small debris. If the bottom becomes a dust and debris magnet as is the surface upon which the epoxy will flow, then this reduces the aesthetics of the final surface.
Therefore, it is advisable to include a larger plastic sheet than the large void and ensure the plastic is well sealed in place. By so doing, you also are able to cover a wide area meaning that epoxy does not leak from the large void into other knots, cracks, or holes, which may be outside the scope of your current project.
Now, it could be argued that one can place a large plastic sheet over the entire project surface. However, this endeavor is risky as a little spill past the large void spreads across the whole bottom of the surface, creating a big mess.
The best thickness of the plastic sheet to use when filling large voids in wood with epoxy is 6 mil (0.1524 millimeters), as this offers excellent durability.
Always wrap a fair bit away from the edges of the void to avoid any weak pressure points. Any weakness or missing to cover a hole could lead to a huge mess to your woodworking project.
Also, if you have chosen to use a low viscosity epoxy for your project, it is absolutely crucial to tape the bottom firmly. At this point, the care given to taping will define the outcome of the project.


Measure out the epoxy that you need for your project, depending on the size and number of the voids.

If your epoxy includes a hardener, keep the measurements accurate because any inaccuracy could lead to the surface curing for too long or too fast.

As a side note, some of the epoxy resins come with measuring pumps that exceedingly ease the measuring. Mix the epoxy depending on the instructions of the epoxy. Slowly start applying the epoxy resin to fill cracks in the wood.

While filling wood cracks with resin, and large ones for that matter, it is absolutely vital to work in phases. Depending on the size of your void and the strength of the tape, divide your epoxy into phases such that you apply then wait for that phase to dry before pouring an additional phase of epoxy.

Without this careful pouring of epoxy into large voids, numerous projects go to the drain due to the unstoppable epoxy leakage. Too much epoxy at once causes too much pressure on the bottom tape that hence causes leakage and is no fun. Also, working in phases keeps you in control of how much epoxy you consume, avoiding wastage in the end.

Additionally, it is important to start from one end of the void or crack while poring epoxy and let the epoxy flow across to the other side, filling the bottom of the void. Failure to follow this step frequently results in big air bubbles underneath or in the middle of the void, which is unsightly as far as epoxy craft is concerned.

For filling large voids in wood with epoxy, we recommend specific products that could be of great importance in improving the look and feel of your final surface.

One is the epoxy you use for your most part, which should be a deep pour epoxy with the crystal-clear feature that allows one not only to mix the epoxy with a pigment but also to make subsequent pour layers to expose the pigment underneath. Two, a durability-based epoxy with features such as ultra UV resistance should be the second layer to ensure a firm surface.


Sanding epoxy

Instead of poring the first layer of epoxy and following it up with its subsequent layer later, then sand all the layers all at once, it is beneficial to sand in between layers because this exercise reveals some of the air pockets that can be filled as once continues to pour the epoxy.

You don’t want to wait for the curing time between layers and still find small cracks and holes just after sanding all the layers. In using resin to fill cracks in wood, it is crucial to hold your sander flat and level. If you start digging with one side of the sander in trying to get rid of the excess epoxy faster, it is highly likely you’ll end up in inconsistencies.


After sanding, then blow all the holes and cracks to eliminate the sanding dust to avoid sand particles getting trapped in the epoxy that would significantly reduce the quality and aesthetics of the woodworking project. If available, use a vacuum blower that is far more efficient than regular blowers.

After this, then your second layer of epoxy should come right in. A trick to do here is to overfill the void just a hair high because the epoxy will sink a bit as it cures.

It is at this point that you want to employ your blow torch or heat gun or any such heat source to get the bubbles out since working with epoxy produces surface bubbles very often, and filling wood cracks with resin is a no exception activity.

Once the top layer is cured, it’s time to go back to the project with the sander to sand the epoxy layers off back down with the wood. No matter how careful you are, it is highly likely that you will end up with little holes. This phenomenon is due to the nature of crevices, some of whose faces face different directions and, as such, may contact the epoxies at different times, thus depriving the surface of some epoxy and leaving small holes.

To eliminate small holes quickly from the surface, one can use a cyanoacrylate glue such as Instant Bond Glue and Accelerator by Titebond. This technique should be repeated if desired results are not achieved, but the first time the glue enters into the surface is often enough to fill holes in wood. Do not forget to sand the glue again right off to ensure a clean surface for your woodworking surface.


Finally, it is a worthwhile activity to fill large voids in wood with epoxy. If large voids are to be cut off from wood, it is highly likely one could lose a big chunk of the wood available for then to the hobby. There are several challenges in the process, especially of preventing leakage and blowing off dust. However, large voids provide the woodworking hobbyist with an excellent chance to show extra detail due to the larger space meaning the surface with epoxy performs its actual function of making its users engaged and excited.

Below is a list of the tools used in Filling Large Voids in Wood with Epoxy

1 Wire brush

2 Wrestling mat tape

3 6 Mil polythene roll

4 Epoxy pigment

5 Deep pour epoxy

6 UV-Resistant epoxy

7 Sander

8 Vacuum blower

9 Cyanoacrylate glue

10 Blow torch

11 Epoxy applier

All the best in Filling Large Voids in Wood with Epoxy!