How To Make Wood Filler With Sawdust


Filling in holes in the timber you are working with can sometimes be a frustrating undertaking, especially with trying to match the color of commercial wood fillers to the same color as your timber. The commercial wood fillers may also change color as they dry, which may make them stand out as an obvious fill on the final product. You may also run out of your favorite commercial wood filler and need an urgent alternative. Fortunately, there is a pretty simple, easy fix for this problem. You can make your own wood filler from sawdust!

To make wood filler from sawdust, you need to mix a little sawdust into a paste, using a binding agent. The resulting paste is used to fill the void in the wood and given time to dry. Once dried, it can be sanded down to a smooth finish. The binding agent can be wood glue, epoxy, CA glue, or shellac.

Commercial wood fillers work well, but it is difficult for these product manufacturers to provide exact color matches to all kinds of wood. Sometimes you will only manage to get a close match rather than an exact match, but should you be looking for an exact match and do homemade wood fillers work?

Why Would You Make Wood Filler From Sawdust?

As we have intimated already, there are a few scenarios where making your own homemade wood filler from sawdust would be appropriate and more convenient.

Color matching wood fillers that are store-bought can sometimes be a daunting task, especially if you are working on a piece you want to sell. The colors on the outside of the wood filler’s container may not match the wood, and you don’t know how they will look after they dry. 

Should you choose a darker color, a lighter color, or a color that closely matches your wood. While you may think that this is an issue with commercial wood fillers, as we will see later, it is also an aspect of concern for homemade wood fillers.

Color matching is not the only reason why one would choose to make wood filler from sawdust at home. You may have an urgent project you need to get out of, and you have run out of wood filler. As an alternative way to get the job done, it is certainly possible to make your own wood filler and complete the project on time.

There are many different recipes for making your own wood filler, and we will discuss a few examples so you can determine which option would work the best for your application.

How To Make Wood Filler From Sawdust

Various different methods are recommended by people for making wood filler from sawdust. The main difference between the various methods is the binding agent used to bind the sawdust together into a paste and then harden into a surface that can be sanded smooth.

First, we will show you the method that is used to make the sawdust wood filler. We will then discuss the binding agents you can use and how each of them performs in this role.

Some of these wood filler recipes work better than others, and we will discuss each one with its advantages and disadvantages, which will give you an idea of which method will work best for your project.

You will only need two basic components to make your homemade sawdust wood filler. Sawdust and the binding agent, but you will need some equipment to get the job done, so let’s get down to some lists.

Tools you will need to make your sawdust wood filler will be the following.

  • A mixing stick or craft stick. I like to use the wide ones because you can use them to apply the wood filler after mixing.
  • A putty knife. Use a putty knife to spread the wood filler into the wood’s deformity and fill all the cavities.
  • A piece of cardboard. Use a piece of cardboard or a scrap piece of wood as a surface on which to mix the wood filler.

Sawdust For Wood Filler

You will need to gather together a pile of sawdust to make your wood filler. To match the color of the piece you are working on, it would be best to obtain the sawdust you need from the same wood piece.

Use a scrap piece of wood from the project to make your sawdust. There are a few different methods that can be used to get the sawdust for the job at hand. If your orbital sander has a dust collection bag, you can sand the scrap piece of wood and then collect the dust from the collection bag.

Another alternative is to take some sandpaper and rub it over the wood to create the sawdust. You can place the scrap wood on a piece of cardboard or a piece of paper to catch all the sawdust.

The finer the sawdust is, the better wood filler it will make. We recommend using a piece of 220 grit sandpaper to produce the sawdust from the scrap wood. You could use a 180 grit, but don’t go below this as the sawdust will become coarser with a lower grit. The coarse sawdust will not diffuse through the binding agent effectively, and the finish on your wood filler will be coarser.

If you have coarse sawdust, you may want to sift the sawdust to extract all the smaller pieces to use in your wood filler.

Mixing Your Sawdust Wood Filler

Gather the sawdust together in a pile in the center of your cardboard or piece of scrap wood. Pour some of the binding agent onto the sawdust and mix it with the craft stick. Don’t just stir the mixture, but press down on it to mush the sawdust into the binder agent.

The consistency you are looking for is a putty-like texture, so if the mixture is still a little too dry, add some more of the binding agent until you reach the desired consistency.

With this consistency, you should spread it with the craft stick or putty knife as you would with normal commercial wood filler.

At this point, you have made homemade wood filler, and it is ready to apply to your project.

At this juncture, we will talk about the different binding agents you can use in your wood filler and what the advantages and disadvantages would be.

Using Wood Glue To Make Wood Filler

Wood glue is an item that every woodworker will have available in their shop, making it a convenient and easily accessible binding agent to make your wood filler.

Most woodworkers would be familiar with wood glue and the strength that it gives to the wood once it dries.

Wood glue works very well in this application to make wood filler with sawdust, and it is easy to apply. The wood glue goes a long way, so don’t pour too much in when you first add it to the sawdust, or the mixture may be too runny.

Because the wood glue does not have much color of its own, it is usually white or a light yellow; it takes on the sawdust color very well. The mixture will be slightly darker than the original wood, but as we will see later, this is not a bad characteristic.

Once the wood glue sawdust wood filler cures, which will take overnight, it will be very hard and sand easily and produce a slightly darker result than the original wood but close to the natural color.

Because of the cured wood glue’s hardness, this wood filler can be used as a structural component to affix joints, for example, or hold dowels in place.

Using Shellac To Make Wood Filler

Shellac is better known as a wood finish, and it is quite popular in this role, and it provides a beautiful finish for wood that not only makes the wood look good but also protects the wood.

But how does shellac fare as a binding agent for sawdust wood filler? The methodology for mixing the wood filler with shellac is the same as with any other binding agent. Add the shellac to the sawdust and mix it to a malleable paste.

Shellac will also produce a wood filler that is slightly darker than the original wood but also makes a thinner consistency wood filler.

The biggest problem with using shellac as a wood filler is that it does not cure a rigid form. It will harden somewhat but will remain soft enough to dent it by pressing it with your finger or fingernail. This filler will generally be softer than the surrounding wood.

For this reason, you would only use this type of binding agent in a decorative piece that is not going to see much wear and tear. It cannot be used as a structural filler to fill knots in the wood to prevent them from expanding or preventing cracks from spreading.

Using Epoxy To Make Wood Filler

Epoxy is a great binding agent to use in your sawdust wood filler, but you need to work a little differently with this product.

Epoxy can have a very quick drying time, so you will need to work quickly when mixing the sawdust into the epoxy. Epoxy also sets rock hard, so it is best to apply the wood filler with a disposable craft stick rather than your putty knife.

You also should be careful not to get much of this wood filler on the surrounding wood, and if you do, you should wipe it off quickly and then wipe the area with a damp cloth or even a cloth dabbed with a little acetone.

Because most epoxy mixes are clear, the color that the wood filler would take on would be closer to the color of the original piece of wood, and in this respect, the epoxy would produce similar results to that of wood glue.

Because epoxy sets up extremely hard, it is an ideal binding agent to use for your wood filler where you need it to provide bonding and structural support. Thus, it is an excellent choice to fill in knots and fill in and repair cracks in the wood.

Once the epoxy has cured, it sands down really well, and you can achieve a smooth surface over the flaw that has been filled.

Using CA Glue To Make Wood Filler

CA glue is another binding agent that works really well when making homemade sawdust wood filler. Because this is glue and it sets quite quickly, this is another case where you will have to work quite rapidly to get the wood filler into the void in the wood before the glue starts to set.

The advantage of CA glue, or superglue, is that, like epoxy, it sets very hard. As a result, the filler made with CA glue can fill cracks and knots, stop them from spreading, and fill a void in the wood.

The wood fille’s color made with CA glue will be similar to the original wood color but slightly darker. You can also get CA glues tinted in different colors, which will give you the ability to try different colors of CA glue to get the desired color for the piece you are working on.

Once the CA glue has cured, it can easily be sanded to a nice smooth finish that feels good to the touch and offers a lot of strength to the wood. Thus, this type of wood filler is also good for repairs as well as for filling voids.

Problems With Making Wood Filler From Sawdust

Even though it is possible to make a wood filler from sawdust and your favorite binding agent, you should be aware of some characteristics of this wood filler before you go ahead and use it.

Many of these characteristics pose similar problems that commercial wood fillers have, so the problems will not be new, but you need to know how it will affect your work’s final look.

Filler Shrinkage

The homemade fillers can sometimes suffer from shrinkage as the wood filler dries. To compensate for this possible shrinkage, you can apply the filler so that it is slightly above the wood’s surface.

The excess filler can then be sanded down once the filler has had an opportunity to thoroughly cure and harden.

Staining Sawdust Wood Filler

When a wood filler is used, whether homemade or commercial, it sets very hard and no longer has the surrounding wood’s absorbent qualities.

As a result, the wood filler will not absorb any stain and will not be affected by the stain. It will not be possible to adjust the color of the fill with a wood stain or dye. 

Because the filler does not accept stain, it is generally a good idea to mix your wood filler so that it is slightly darker than your original wood. If you are using light-colored wood and staining it a darker color, you should make your wood filler from a darker wood than your original piece.

This will make the filled section blend in better with the wood after the stain has been applied to the lighter wood.

Even if you are not staining the wood, you should have the wood filler slightly darker than the original wood because wood darkens as it ages. This means that if the filler is darker, it will blend in with the wood more and more as the surrounding wood darkens with age.

Finishing Over Sawdust Wood Filler

You can put your normal finish over the wood area that has been filled, but depending on the type of finish used, you will get different results.

An oil-based finish will not affect the filled area, but the filler will not absorb any of the finish. Thus, the surrounding wood will absorb the oil finish and become darker, but the filler material will not.

If you are applying a varnish or a polyurethane coating over the wood, you can put this over the wood filler. The coating will go over the wood filler and dry to the same finish as if applied to wood.

Conclusion

Making your own wood filler is a practice that many home woodworkers are trying out, sometimes because of the convenience, sometimes for the better color matching, and sometimes simply as a cost saver.

While commercial wood fillers work well, they tend to be fairly pricey, especially compared to the cost of a little wood glue and a small pile of sawdust.

As with any of these types of homemade alternatives, you will need to experiment with making your own sawdust wood filler and see how well it works for you and whether you are willing to adopt it as your go-to filler whether you want to stick with a commercial product.

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