Whether you have a large wood project, a nice wooden table, or a big wooden patio deck, sooner or later, damage and degradation can happen. If you have anything made of wood that has large holes in it, instead of just throwing it away, you can fill those holes, and in fact, there are several ways to do so.
With that, let’s talk about the eight best ways to fill large holes in wood.
Method #1: Sawdust and Wood Glue
One of the best and easiest methods for filling large holes in wood is by using a combination of wood glue and sawdust. This is a great method to use for even the largest of holes, and it works for holes that both pass all the way through wood and for those that do not.
All it involves is applying a thick layer of wood glue to the hole, filling it with sawdust, and then sealing it with a thick layer of wood glue overtop.
If you are really worried about the hole opening back up, you could even mix sawdust with a large quantity of wood glue to make your own home-made wood filler paste. If you are using this method, make sure to mix equal parts wood glue with sawdust. We recommend using the latter method over the former.
Just make sure that the color of the sawdust and the wood glue match the color of the original piece of wood. What is also convenient about this method is that sawdust and wood glue can both be sanded and painted once dry.
Pros:
- Can be used for all sizes of holes
- Dries relatively fast
- Easy to sand and paint
- You can use sawdust from the same variety of wood to color match
Cons:
- Can go wrong if you don’t mix the glue and sawdust using proper proportions
- Staining wood glue is not easy
- May shrink as it dries
How to Do It (Homemade Glue/Sawdust Filler)
- If the hole passes all the way through the wood, tape off the bottom with a thin piece of wood or cardboard.
- Mix equal parts wood glue and the sawdust of your choosing. Mix it thoroughly.
- Fill the hole with your mixture, let it dry, then sand and paint it.
Method #2: Wood Filler
Wood filler, a product that features medium viscosity, is a great way to go for medium size holes. Wood filler is usually made of epoxy, polyurethane, or clay, and sometimes contains wood fibers.
Keep in mind that wood filler doesn’t stand up too well to harsh conditions, so it’s only ideal for indoor use. It’s also not overly adhesive, so you may have to seal it off with extra adhesive when finished.
That said, wood filler is ideal for filling holes that do not pass all the way through wood, as it is a bit runny and not overly thick (although it can be used for full holes), it dries relatively quickly, and it can be sanded, painted, and varnished. Wood filler also tends to be easy to clean.
Pros:
- Can be sanded and painted
- Dries quickly
- Fast and easy to use
- Ideal for medium-large holes that don’t pass all the way through
- Many types available
Cons:
- Not ideal for outdoor use
- Requires a lot of sanding
- May require a layer of adhesive for a good seal
- Not ideal for extremely large holes
How to Do It
- If the hole passes all the way through the wood, seal off the backside with some spare wood or some good tape.
- Clean the area and give it a once-over with some rough sandpaper.
- Fill in the hole with the wood filler, let it dry, and then sand and paint as needed.
Method #3: Dowels and Wood Glue
One very unique way to fill large holes in wood is by using wooden dowels and wood glue. This method is best used for large and cylindrical holes, such as if you made way too big of a hole with a power drill or a drill press. Dowels are best used to fill relatively deep and narrow holes that are circular in shape. This is because all you have to do for this method is to cut a dowel down to the appropriate size, give it a few score lines to allow the wood glue to adhere, cover the dowel in glue, and shove it into the hole.
This method is only ideal for long and cylindrical holes, but it can be used on slightly wider holes as well. You would just have to tie or glue several dowels together to increase the overall circumference.
Pros:
- Fast and easy
- Wood glue dries fast
- You can sand and paint it once dry
- Ideal for long and cylindrical holes
- Cost-effective
Cons:
- Wood glue can shrink as it dries
- Wood glue is not easy to stain
- Not ideal for holes that are not long and circular
How to Do It
- If the hole passes all the way through, seal the backside off with tape.
- Cut a wood dowel down to the right size (same length as the hole).
- Score the dowel along its length a few times to allow the glue to adhere, and then cover it in glue.
- Pop the dowel into the hole, rotate it a few times to spread the glue, and then if need be, fill in any remaining gaps with wood glue.
- Let it dry, then sand and paint it.
Method #4: Toothpicks and Wood Glue
This method is very similar to the one discussed above, but because toothpicks are much shorter, this method is best used for holes that are only a couple of inches deep, although if the hole is very wide, you can glue several toothpicks together to increase their diameter.
This method can be used for both indoor and outdoor applications, the glue is easy to sand and paint, it dries fast, and it’s cost-effective too. That said, it’s really not ideal for very deep holes, or holes that are not circular.
Pros:
- Affordable
- Wood glue dries fast
- Can be sanded and painted
- Ideal for shallow and wide holes
- Can use multiple toothpicks to increase the diameter to suit wide holes
- For indoor and outdoor use
Cons:
- Not ideal for deep holes
- Wood glue is hard to stain
- Not ideal if the hole passes all the way through
- Can be messy
How to Do It
- If need be, tape off the other end of the hole, if it passes all the way through the wood, although this method is not recommended if the hole passes through to the other side.
- For small holes, a single toothpick might due, but realistically, you will have to bunch several together to fill wide holes.
- If you need to bunch toothpicks together, you will need to slather all of them in glue.
- Put some wood glue in the hole, get your glue covered toothpicks, and put them in the hole.
- Fill in any gaps with more wood glue.
- Let the glue dry, sand it, and then paint it.
Method #5: Epoxy
Using epoxy to fill medium holes is another option at your disposal. The benefit of using epoxy is that it creates a very tight bond, a strong seal, it’s super weather and temperature resistant, and very permanent too. Two-part epoxy is very strong, and it’s not hard to use either.
That said, this stuff is pretty thick, so it’s best used for wide and shallow holes rather than deep and narrow holes, as it is very thick and won’t really run-down narrow spaces.
Moreover, due to the nature of epoxy, it is also not suited for holes that pass all the way through wood. Quality two-part epoxy also is not cheap, so if you need a lot of it, you will end up spending a good deal of money. Finally, sanding and painting epoxy is also not really possible.
Pros:
- Ideal for wide and shallow holes
- Ideal for indoor and outdoor use
- Weather-resistant
- Very tight bond
- Usually dries fast
- Relatively easy
Cons:
- Not ideal for deep and narrow holes
- Fairly expensive
- Not easy to sand and paint
How to Do It
- Mix the two-part epoxy according to the directions.
- Apply it to the hole as quickly as possible and smooth it out before it dries.
- Let it dry. You can attempt to sand it, although it won’t work well.
- If the hole is both deep and wide, you can fill it with sawdust before applying a thin layer of epoxy over it, which will help cut down on your cost.
Method #6: Putty – Bondo (or Similar Products)
Wood putty is similar to wood filler but much thicker. This is why using wood putty is ideal for wide holes that don’t require the filler to run down into cracks. It is ideal for holes that pass all the way through wood, as long as they are not too narrow.
Wood putty is also ideal for both indoor and outdoor use, as it forms a very tight bond that is also weatherproof. It also has the ability to resist shrinking, plus it can expand along with wood as it expands.
However, wood putty does take a very long time to dry, and it may also change colors as it dries, depending on the weather and light conditions. Moreover, wood putty may actually damage raw wood, so it should only be applied on top of a sealant.
In case you are wondering, you might also want to read about how long Bondo takes to dry.
Pros:
- Ideal for wide holes
- Can be used if the hole passes through the wood
- Very tight bond
- Weatherproof – ideal for outdoor use
- Does not need to be sealed once dry
- Resistant to shrinking
- It expands as wood expands
Cons:
- Thick and hard to apply
- Not ideal for narrow holes
- Long drying time
- Can damage raw wood
How to Do It
- If the wood is raw, apply a sealant first.
- Mix your putty very well so it has an even and smooth consistency.
- Use a trowel or spackle applicator to fill the hole.
- Let it dry.
Method #7: Spackle
Spackle is mostly used to repair defects or holes in drywall and concrete, but can also be used to fill holes in wood. Keep in mind that spackle is thick, so it is best used for shallow and wide holes.
Spackle is great because it comes in many colors, dries very hard, works for large holes, sands well, and it can be painted. The downside is that it’s not weather-resistant, stain is not easily applied, it may shrink, and you may need to apply several coats of it. However, it is quite cost-effective.
Pros:
- Good for shallow and wide holes
- Dries solid
- Good for larger holes
- Can be sanded
- Can be painted
- Easy to apply
- Cost effective
Cons:
- Stain does not hold well
- Not overly resistant to damage
- May shrink
- May require a couple of applications
How to Do It
- Prepare the area with light sanding and wipe with a clean cloth.
- Apply enough spackle to fill the hole and completely cover the area.
- Push the spackle into the hole with the putty knife and scrape off excess.
- Let it dry completely, then sand as needed and clean off with a damp cloth.
Method #8: Acrylic Caulking
The final method you can use to fill holes is by using some simple acrylic caulking and a caulking gun.
Caulking is a good way to go for simple repairs where you don’t need to sand or stain anything after, more or less for filling holes and gaps. It’s good for outdoor use due to its resistance to moisture, plus a caulking gun is very easy to use too. That said, caulking is not cheap and it’s also not ideal for very large holes.
Pros:
- Good for exterior use (read my tips for exterior caulking)
- Moisture resistant
- Easy to apply
- Comes in different colors
- Ideal for repairs
Cons:
- Cannot really be sanded or painted
- Not ideal for narrow holes
- Not overly cost effective
How to Do It
- Clean the area.
- Apply the caulking.
- Let it dry.
Summary
As you can see, there are many good ways to fill large holes in wood. Which method you choose depends mostly on your needs and the size and shape of the hole in question.
To avoid having to deal with this issue in the future, you might also want to see my article about how to stop a crack in wood from spreading.