5 Best Ways to Fill Large Gaps/Holes in Wood

By MWB-Team •  Updated: 06/06/23 • 

Large holes and gaps in wood affect the overall aesthetics and integrity of the wood’s surface. Whether the holes or gaps are caused by excessive stress, mechanical damage, knots, natural defects, or rotting wood, they can be fixed. In this article, we look at the five best ways you can effectively fill large gaps and holes in wood.

1. DIY Wood Glue and Sawdust

This is an easy and DIY-friendly method of fixing both large and smaller holes in wood. Making your own wood filler is very easy, and you’ll use readily available products – wood glue and sawdust. This method works by mixing sawdust and wood glue to a thick consistency to produce a paste that can be used to fill holes, cracks, and gaps in the wood.

Wood Glue and Saw Dust

Wood Glue and Saw Dust

Once properly mixed, apply the sawdust and wood glue paste to the hole or gaps and leave it dry. Once dry, sand it down to leave a smooth and seamless surface. For better results, use sawdust from the wood you’re filling. You can also stain the sawdust before applying it to the hole if you’re repairing a finished piece of wood project.

Although this is a fast and easier method of filling defects in the wood, the wood glue and sawdust can shrink once it dries. The type of wood glue you use might also be harder to stain and stick out once you stain your wood project.

2. Use a Wood Filler

Apart from using a sawdust and wood glue mixture, you can try a wood filler. Wood fillers come premixed and usually contain a sauce and a binder, which can be wood glue, varnish, or lacquer. Most wood fillers come ready to use and can be applied to holes, gaps, and other wood defects.

Minwax Stainable Wood Filler

Minwax Stainable Wood Filler

Wood fillers can be classified into two main categories – water-based and oil-based. Water-based wood fillers have sawdust suspended in a water-soluble binder. These have less odor and dry up quickly, which makes them great for indoor use. However, like sawdust and wood glue mix, water-based wood fillers can also shrink to a certain degree.

Oil-based wood fillers have sawdust suspended in oil, petroleum, and other solvents. They are more durable and waterproof than water-based wood fillers, making them great for outdoor use. They are also stronger and are typically used to fill larger gaps in the wood.

If you’re looking for a wood filler that will take up stain better, check it this post we did a while ago on the best stainable wood fillers.

3. Epoxy & Epoxy Filler

Epoxy has grown in the woodworking world from river tables and other aesthetic designs achieved with wood. It is great for filling up larger holes and gaps with colorful dyes and pigments for cool and beautiful effects. Epoxy works well because it adheres to wood like glue and forms a hard surface that can be nailed or drilled.

Epoxy also comes as a wood filler and is more durable than other types of wood filler and also dries into a harder finish. Also called 2*-part epoxy fillers, this wood filler can fill larger holes and gaps or be used to form a missing chunk of the wood.

Epoxy wood fillers come in a paste consistency, just like wood fillers. However, with epoxy fillers, you also get a separate hardener mixed just before applying the filler. When combined, the mixture of epoxy filler and hardener produces heat, so be careful when handling. Once mixed, you have to use the mixture fast as the hardener starts to work immediately.

4. Apply Wood Putty

Wood putty is a malleable mixture of solid materials like sawdust, wood flour, or calcium carbonate and a binder such as glue, finish, or gypsum (plaster of Paris). Unlike wood fillers, wood putties are used to repair a wood surface that has already been stained or finished. Because of its composition, wood putty remains malleable after being used.

DAP Latex Plastic Wood Filler
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This is a water-based wood putty that is formulated with natural wood. It is available in different color finishes to match your wood finish better. It's easy to apply and can be sanded to make a smooth finish.

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Wood putty should not be used on bare wood because it contains chemicals that could stain it. It is best used to fill holes and gaps in wood projects that have already been finished. Before applying a wood putty, you can mix it with the stain to better customize it to your finished wood project.

Because it does not completely harden, wood putty can also be used outdoors and withstand temperature and humidity. Check out our guide on wood putty vs wood fillers for a comparison between these two.

5. Dowels and Wood Glue

This is a great way of fixing bigger holes and gaps in the wood. Dowels are great for covering larger cylindrical holes left behind from drilling or knots. To fill a cylindrical hole in the wood, you have to cut a dowel that will fit perfectly into the hole you’re looking to repair.

Filling a Hole With a 
Dowel

Filling a Hole With a Dowel

Once you’ve cut the dowel to the right size, apply glue to the filled hole and insert the dowel. Once the glue dries up, cut the dowel to flush with the wood and sand it for a seamless and smooth finish.

MWB-Team

Hello there! This is the Make Wood Better Team. Here, we share informative how-tos and guides focused on making wood better. Whether it's finishing wood, maintenance, or restoration, there's something on this website for you to learn and improve your skills.