How to Fill Cracks in Wood (4 Creative & Easy Ways)

Your project’s appeal could be severely diminished by a wood crack, or worse yet, you could be told to throw the wood or the whole thing away.

Fortunately, there are several methods you may employ to fill a wood crack without discarding the wood. I will thus go over how to fill cracks in wood in this article.

Before sealing any cracks in wood, it is essential to determine the size of the crack. To fill small cracks, use wood putty, wood filler, or homemade wood filler. Epoxy is effective in filling larger cracks. Another important factor is how the wood is finished. I shall go into deeper detail in this manual.

So if you find a crack in wood or in one of your projects, thanks to this in-depth article, you’ll discover the key ways to solve each wood splitting challenge. Thanks to the useful tips you will be able to make the right choice for your workpiece, how to best prepare yourself before filling cracked wood, and how to fill the wood crack for a perfect and long-lasting result.

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How to avoid cracks in wood

A project can be utterly ruined by flaws. Although it decreases value, it can also shorten the project’s lifespan.

This article teaches you how to fill cracks in wood once they appear in a completed job. However, you can also stop the wood from cracking so that you won’t need to fill it in the future.

I produced an article chock-full of helpful advice to avoid how the wood would fracture. You should read this post to learn how to prevent your projects from cracking.

What to look for before you start filling cracks in wood

Before you start pushing any wood filler into a wood crack, it is good to think about the best way of working and which wood filler is most suitable. Only in this way will you obtain the best result that will last a long time. There are several ways to repair split wood. The method you choose will depend on the type of wood cracks and the type of finish on the wood you want to repair.

Determine the type of cracks

Small wood splits can be secured with wood glue, clamping the gap and allowing the wood to dry overnight. If the cracks are really small, you can use a syringe to inject the wood glue into the crack to have the best results. I made a #shorts video on my YouTube channel with this tip, which you can watch below.

For wider crevices, you will need the help of wood fillers, which I will discuss further in this article.

For really large and deep cracks that run through the thickness of the wood, it is wise to use shims or plugs to repair the wood crack. It is best to take a piece of wood of the same type of wood and make a shim or plug that fits as well as possible in the crack you want to repair. Then you can fix the crack by adding this piece of wood together with wood glue. Another way is the use of Epoxy.

Take the final finish into account

Examine the wood’s surface and finish carefully. If your wood is waxed or polished with oil, you cannot use any wood filler. Therefore, it will be necessary to match the type of wood filler to the wood’s final layer.

To better inform you about this, I wrote the article, What Wood Filler Is The Best To Use? 3 Types Clearly Explained! If you want to know more about how to finish the wood, my article 4 Types Of Wood Finishes. What To Use When And How? A Clear Guide is recommended reading.

How Do You Prepare Cracked Wood For Filling?

Before we go over to how to fill cracks in wood surfaces, special prep work is required. Afterwards, paint may be required. Due to meticulous preparation, the finished wood will appear smooth, orderly, and durable. To assist you in preparing your cracked wood for painting, refer to the following guidelines.

Step 1: Prepare your work area

Make sure your workspace is appropriate for employing the goods you need to patch wood cracks before you begin. To prevent spilling used products, wrap the items close to your desk with plastic.

To prevent breathing in fumes when working indoors, ensure sure the space is properly aired. To prevent splashing materials on yourself, you should also wear gloves and appropriate work attire.

Step 2: Inspect the entire wooden surface.

Always examine for any difficult-to-see damage on the entire treated wood surface. Smaller wood cracks or holes could be hard to spot at this point, but they might become apparent while applying the final coat. You have to start afresh in order to patch these cracks.

Step 3: Repair The Damages On the Wood

Fill up any openings or cracks with one of the filling techniques you can learn more about in this post. Consider the ultimate finish of the item as you search for the best filling technique that will work with the wood you wish to restore.

Use a scrub brush or metal scraper to remove the old paint from painted surfaces before restoring them. You can use a sander or a hand sander to remove the stain off larger projects. Use only appropriate sandpaper. I previously created the post A Clear Sandpaper Grit Chart & Guide | All Info In One Place to help you choose the best sandpaper for your project. This page has a ton of information, so make sure to read it.

In addition, you can use chemical paint strippers to remove old paint; however, be sure to read the manufacturer’s instructions for proper use if you choose to use chemicals.

Step 4: Sand the surface after the wood filler has dried

Remember that the wood filler you used must have properly cured before you can move on to this stage. Therefore, always refer to the usage instructions provided by the manufacturer.

Use an electric sander or hand sandpaper for sanding. Start with coarse sandpaper, then move on to sandpaper with a finer grit as the surface gets smoother.

Sanding is a step that you should never skip. Sanding makes the wood surface rougher, allowing paint and primer to cling to it flawlessly. Additionally, it evens out the wood, particularly after applying wood putty or putty, providing a smooth surface for painting.

When sanding, always follow the same direction as the grain of the wood and remember to wipe off all sand dust, and dirt, as paint cannot adhere to dirty surfaces.

Step 5: Finishing

Now it’s time to finish the wood and make it match the rest of the project. Finishes come in various forms, such as oils, stains, paints, and so on. I previously wrote several articles about wood finishers, which you can find in this list.

Once you have completed all the steps above, your wood surface is ready.

How to fill cracks in wood

With all the knowledge you’ve gathered from the beginning of this article, you can move on to learn how to fill cracks in wood. Below I discuss 4 different ways and to make it a little easier for you, I’ll write down each way for which it is best suited.

Filling Cracks With Wood Putty

This is best suited for small cracks up to 3 mm (1/8 inches) in wood that has already been stained.
I recommend using the wood putty below.

Step 1: Choose a filler that complements the color of your wood

Choose a wood putty color that complements the wood you are treating from the many shades available.

Buy various colored fillers and mix them to make various colors until you discover one that blends well if you can’t find the exact hue of your wood.

Step 2: Fill the crack with filler.

Spread your filler over the wood crack using a putty knife. To ensure that the crack is entirely filled, keep applying the product until the crack overfills and the material protrudes from the crack.

Prior to the excess material drying up, flatten it out with a putty knife or your fingertips. In order to avoid leaving dirt on your surface, only use a clean rug to smooth out the filler.

Step 3: Let the filler dry.

The product you select will determine how long your filler needs to cure properly, so check the manufacturer’s label for the suggested dry time. To be safe, let the treated wood dry for at least eight hours or overnight to make sure the filler has completely dried.

Step 4 is to sand the extra filler down.

At this point, some filler will still be visible even after being smoothed away with a putty knife. The cracked area can be repaired with a plane or fine-grit sandpaper. The filler should be worn down until it is as flat against the wood as possible, using sandpaper with a grit between 220 and 320.

Filling Cracks With Wood Filler

Wood filler is best used if you have cracks up to 10 mm (3/8 inches) that are in bare wood and will be covered with paint. I recommend using the wood filler below.

Step 1: Sand the area where the putty will be applied.

Sanding the surface allows you to remove any debris and roughens it up so that the wood filler will stick nicely. To complete this process, you can use sandpaper that is coarser. Here, 120 grit sandpaper is what I advise using. Here, manual sanding is preferred.

Step 2: Remove all debris and dust.

To get rid of all dust and filth, use compressed air or a dry cloth. The correct bonding of the wood filler may be hampered by any lingering dust or grime.

Step 3: Use a putty knife to apply the putty.

In order for the filler to protrude, press it firmly and apply a bit too much of it.
There is a possibility that the filler will be set if it dries out. It is wise to fill larger cracks in layers rather than all at once. This will hasten the drying process and lessen the likelihood of sunburn later.

Step 4: Wait 20 minutes or so for the filler to dry.

Take a close look at the packaging’s description of what the manufacturer suggests here and pay close attention to it.

Step 5: Sand off extra filler to create a level, smooth surface.
For this, use finer sandpaper, such as 220 grit.

Step 6: Apply a finish, like for example stain or paint.

Filling Cracks With Wood glue and sawdust

I have to admit that while this is probably the simplest and least expensive approach to fix wood cracks, experience has shown me that it isn’t always the greatest option. But with DIY wood fillers like this one, issues can occur. You can learn more about them in my post, 5 Common DIY Wood Filler Problems When Using It (The Truth).

This technique makes it simple to patch cracks up to 10 mm (3/8″) in diameter.
To cover the crack after using this DIY filler, a finishing coat like as paint must be used.

Step 1: Provide sawdust that matches the type and color of your wood.

Since you’ll be using sawdust to coat the white wood glue, it should roughly resemble the wood you’re treating. To get a precise mix, sand or cut the wood you are using to remove some sawdust. The collection bag for the sander contains the best material. The approach works well with this fine sanding dust.

Step 2: Squeeze the wood glue into the crack.

Take the wood glue bottle, place the nozzle against the crack, and squeeze until the glue fills the entire opening. To guarantee the adhesive goes inside small cracks, think about using a syringe.

Step 3: Sawdust over the adhesive.

Put a lot of sawdust on top of the glue and cover it fully. Make sure the adhesive is holding the sawdust in place by running your fingertips down the crack. In this manner, the sawdust completely conceals the glue’s white color and harmonizes with the rest of your wood.

To ensure that the glue dries well and the crack is difficult to see, it is advisable to let it sit overnight. Reapply the wood glue and sawdust mixture if necessary, or try a different putty, if the gap is still noticeable the following day.

Step 4: Sand the glue away.

Use fine sandpaper to gradually sand the treated area until the filler is flat and undetectable.

Filling Cracks With Epoxy

The last in the list of methods on how to fill cracks in wood is epoxy. Epoxy is a 2 component resin-based filler. By mixing the resin and the hardener, you obtain a hard mass. Learn how to do this properly in my guide How to Mix Epoxy Glue Properly: A Clear Step-by-Step Guide to Success

Above that, you can add color pigments to give the resin any color you wish.
All wood cracks larger than 10 mm (3/8”) can be filled with epoxy.

Epoxy seems like a more difficult method to use for filling cracks, but trust me, all in all, this technique is quite easy once you’ve done it. However, keep in mind that there is a difference between epoxy as a filler and epoxy glue. Use each of them for the right purposes.

Step 1: Safety first.

Before applying epoxy to your wood, put on a respirator to safeguard your health because the fumes can be dangerous. When working away from your dogs and other family members, think about doing it outside or in an area with sufficient ventilation.

Step 2: Tape over the tear with masking tape.

If the damage to your wood is too extensive for it to pass through, tape the back using masking tape. The tape will keep the filler in place for long enough for it to set in the crack.
If you are curious to know what types of tape you need for woodworking, you should check out this article.

Step 3: Mix the epoxy components.

Two ingredients make up epoxy: resin and hardener. Calculate how much you will need to fill the wood crack, and then add it to a bowl in equal quantities without mixing it, as the epoxy will begin to cure as soon as the two ingredients are joined.

Step 4: Add color to the epoxy.

The color of the epoxy won’t match the color of your wood, so look for a wood-colored dye or powder pigment that goes with your project and add a drop or two to color the epoxy. When the mixture turns into a paint-like consistency after a brief period of stirring to thoroughly combine all ingredients, your epoxy is ready for use.

Step 5: Insert the mixture into the crack.

Using the stirring spoon, pour the filler into the crack. Because most of the liquid will flow to the bottom, if you don’t have enough resin to fill the crack, make some more until you do.
In epoxy, air bubbles can frequently become caught. You may easily bring this to the surface by heating the epoxy.

Step 6: Let it dry.

Due to epoxy’s rapid drying, your wood will be ready in two to four hours. To be safe, wait until it has totally dried the following day before sanding.

Step 7: Level the filler.

Remove any surplus filler with a putty knife before using fine-grit sandpaper to level the surface.

How to fill cracks in wood – conclusion

If you want to start filling cracks in wood, you need to take into account the size of the crack and the type of finish of your project. Then you can choose whether you work with wood putty, wood filler, a DIY wood filler, or epoxy. Thanks to the tips in this article, you now know perfectly which method to use on how to fill cracks in wood for the best results.