Wood Putty vs. Wood Filler – Differences, When to Use Each

By MWB-Team •  Updated: 06/04/23 • 

In the woodworking world, wood putty and filler serve the same purpose. After all, both are used for filling and repairing holes and damage to wood. However, these two are different in their composition, down to their differences in usage. This article will explore their differences and when to use each.

What is Wood Putty?

This malleable material is made from a mixture of plastic- and oil-based solvents. It is also called ‘plastic wood,’ one of the most popular wood repair compounds to fill holes and fix defects. Because of its composition, wood putty does not harden, shrink, or crack. It is also soft and very pliable, making it easy to apply.

However, wood putty is not recommended to be used on raw wood. This is because of its chemical composition, which can damage raw wood rather than repair it. Instead, if you’re using wood putty, make sure the wood is stained, sealed, or painted to create a barrier against chemical action.

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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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Another reason to apply wood putty on finished wood is that wood putty does not take a stain well. If applied to raw wood, it might look different once it dries. Wood putty comes in different colors, which you can mix to get a perfect match to your finish.

When To Use Wood Putty

What is Wood Filler?

Wood filler is usually a mixture of sawdust and a binder which hardens as it dries. The binder can be wood glue, lacquer, or varnish.

Once it is properly mixed, a wood filler can be used to fill imperfections in both finished and unfinished wood. However, wood filler is usually recommended for unfinished wood so it can be sanded once it dries before finishing.

Wood Filler Drying Before Sanding

Wood Filler Drying Before Sanding

There are two types of wood fillers available – water-based and petroleum-based. Water-based wood fillers use sawdust and a water-soluble binder. These have less odor and dry up quickly, which makes them great for indoor use. Petroleum-based wood fillers use petroleum-based binders, which makes them durable and waterproof, ideal for outdoor use.

When To Use Wood Filler

Wood Putty vs. Wood Filler Differences

Sanding

Wood filler can be sanded, which is why it is applied and sanded down later on to get a smooth finish. However, wood putty cannot be sanded and is usually smoothened out using a putty knife.

Usage – Finished vs. Unfinished

Wood putty is good for use in finished wood products. This is because of its chemical composition, which can affect raw wood. It is also easier to match the color of wood putty to your wood once it is finished. Wood filler is good for unfinished wood because it bonds well and can be stained or finished to match the wood. Check out the best stainable wood fillers you can use for a flawless wood finish.

Outdoor Application

For outdoor use, wood putty is better because of its elasticity. Wood putty does not harden and can change in response to changes in temperature or humidity. Wood filler will crack when subjected to changes in temperature and humidity. Although petroleum-based wood filler can be used outdoors, wood filler is usually recommended for indoor use.

Ease of Use

Wood putty is easier to use for both amateurs and DIYers. It is easy to apply and available in many colors, making it easier to match different finishes. For minor scratches, wood putty can be applied perfectly without much preparation. On the other hand, wood filler might need to be shaped, sanded, or refinished, which might be harder for beginners looking for a quick fix.

Drying Time

If you want to repair your wood quickly, wood fillers dry up faster than wood putty. Most wood fillers can be sanded in about twenty minutes and finished/refinished in about an hour. However, the drying time will vary based on the brand of filler you use. All the same, if you’re looking for a quick repair, wood filler is a faster option to use.

Durability

Wood putty is your best option if you’re looking for a durable option. This is because it remains flexible and responds better to changes in the wood because of temperature and humidity.

In terms of storage, wood putty can last over ten years when properly stored. This can be handy in repairing wood products even years after initial use. On the other hand, a wood filler can last for about three years when properly stored. However, it also hardens as the resin binder evaporates.

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.