Wood Putty vs. Wood Filler: Which to Choose?

Wood Putty vs. Wood Filler: Which to Choose?

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Wood putty and wood filler can help fix our woodworking mistakes. They are both very similar, however, there are some key differences. When you understand the strengths and weaknesses of putty and filler, you’ll know precisely the right time to use them.

Keep reading this article to improve your woodworking knowledge and learn all about the two materials.

Wood Putty and Filler: The Basics

Before we get into the details, let’s explain exactly what wood putty and filler are. It’s quite common for shops to not properly define if a product is one or the other.

This is why it’s important for you to know, so you can make a decision yourself.

What Is Wood Putty?

Wood Putty Wood putty is a newer product than filler and is usually made from a combination of oil-based solvents and plastic. Even when dry, putty remains flexible and malleable. You can’t sand wood putty because it doesn’t harden, if you tried, the sandpaper would clog up quickly.

Wood putty is designed to fix damage to wood that is already finished, like scratches, dents, and nail holes. Wood putty comes in a huge variety of shades, so it can be matched to the finished tone of the wood you are repairing.

For instance, if fixing a scratch on cherry wood, you could get a putty that has a more red pigment to it. Similarly, if you are repairing a piece of ash or white maple, you would use a lighter-toned putty, with a bit of white pigment.

What Is Wood Filler?

Wood Filler Wood filler has been around for centuries in different forms and recipes. In its simplest form, wood filler is a combination of a binder and sawdust. This type of wood filler can be made very easily and quickly when needed, just mix sawdust with glue in a container.

Wood filler is designed to harden, and this means it can be sanded. A filler is usually applied before a finishing coat is put on. The filler is then sanded back, and the remaining jobs can be completed. Most fillers will take a stain as well, so they can be hidden effectively.

Wood fillers can be either water-based or oil-based. Some fillers that share the same base can be mixed to adjust their color to match the tone of the wood better.

Similarities of Wood Putty and Wood Filler

Wood filler and putty share multiple similarities, in this section, we’ll discuss what they have in common.

1. Application Method

Most fillers and putties are applied with a filling knife or a scraper. The filling knife creates a smooth layer just above the face.

2. Materials They Are Used On

Both filler and putty are designed to be used with various kinds of wood. Depending on the product, some are suitable for exterior use and some for interior.

3. Objective

When you use wood filler and putty, the objective is the same: you want to repair damaged wood, regardless of whether that damage was caused by you or is natural like a knot hole.

4. Shelf Life

If correctly looked after, wood putty and filler can last for years. The key to storing them correctly is keeping air away from the product. Air will start drying the products out. Once they have dried, most filler and putty is unusable. Some water-based products can be reactivated by mixing them with water though.

Differences Between Wood Putty and Wood Filler

In this section, we’ll outline the critical differences between wood putt and wood filler.

1. Time It’s Used in the Build Process

Wood filler is used to repair wood before sanding and finishing. Without sanding and finishing the filler, it would be extremely obvious and not pleasing to the eye. Putty, on the other hand, is applied as a final step, after sanding and finishing it completed.

2. Structural Properties

Neither wood filler nor putty are safe for structural usage. However, a filler is capable of holding a larger shape if, for example, an edge or corner needs repairing. Putty can’t retain its shape as well as filler and should be used carefully in larger quantities.

3. Hardening

A filler dries until it is completely hard. Comparatively, a putty never completely dries out and never hardens fully. Because of this, putty remains malleable.

4. Staining

A wood putty does not take a stain or finish, whereas a wood filler does. If you need to stain, the best wood fillers for this have a higher proportion of wood particles in them.

5. Timber Movement

Timber will move and distort based on environmental conditions. Humidity and temperature fluctuations will cause the wood to move, expand, twist, bow, and distort.

A wood filler doesn’t move once it’s hardened. Because filler doesn’t move, it won’t change with the wood through varying temperatures and humidity. As a result, cracks can appear over time. Putty remains malleable and can adjust to timber movement, making it less likely to crack.

6. Materials They Are Made From

The base ingredients of filler and putty and fundamentally different. Putty is composed of plastic and chemicals, whereas filler will have sawdust or wood fibers within it.

Wood Putty vs. Wood Filler: Which One Should You Use?

Deciding if you need wood putty or wood filler comes down to understanding a few critical criteria.

If the damage occurs at the very end of a build, after the wood has a finish applied, you should use wood putty. If the damage occurs prior to sanding and applying the finish, you have a choice to use filler at that moment or wait until the end of the build to use putty. If a large area needs repairing, consider using wood filler and applying it in stages. A putty would not work in this circumstance because it doesn’t harden completely.

The final finish of your project will also impact the decision between wood filler and putty. Large areas of filler don’t look good. If you are leaving the grain of the wood visible, you should consider doing a repair with putty and matching the tone and grain. However, if you paint the wood, the filler can be completely covered up and won’t be visible at all.

Wood filler is a better choice if there is a shaped edge because it holds its shape. On the other hand, putty would not hold the shape well and would distort with time.

For exterior use, you want to use a strong 2-part filler. This hardens much stronger than putty and can stand up to the stresses of being outside. Putty is generally not suitable for exterior use as it would quickly fall away.

Can You Use Wood Putty Instead of Wood Filler and Vice Versa?

In some circumstances, you can interchangeably use wood putty instead of wood filler. For example, minor dents, gaps, cracks, and scratches can all be repaired with either product.

However, in a lot of circumstances, they can’t be switched out for one another. This is because putty doesn’t take a finish like a filler does, meaning that it can’t be used before sanding and finishing. Similarly, you shouldn’t use a filler once the product has been finished because it needs another layer of finish applied over the top of it, this would create a patch on the surface.


On the surface, to people new to woodworking, wood filler, and wood putty might look like the same product. This isn’t helped by the lack of information some manufacturers give on the packaging. However, there are key differences that it’s important to know about. With this information, you can repair your woodworking project with the most suitable product.

The biggest difference between the two products comes from putty being plastic and chemical based, whereas filler contains wood particles. Filler dries hard and putty retains malleability. Alongside this, a filler can be stained and finished, whereas putty cannot.

Deciding on the right product really depends on the project you’re working on and at what stage you’re at with it. If you’re right at the very end and just need a quick touch-up, then use a putty. However, if you are just at the start of the work, then filling the damage is a better choice, particularly if the project will be painted or the damaged area is not visible.

On a separate note, you might also want to learn about the differences between wood glue and wood filler.