Wood Putty vs. Wood Filler: What’s the Difference?

When repairing furniture and other wooden items or building them from scratch, there are many instances where you will need to fill holes. These holes can be a result of defects or inconsistencies in the wood or where the nails go in.

And when it comes to filling holes in a workpiece, wood filer and wood putty are always the best and in most cases the only solutions.

Wood putty and wood filler are often used interchangeably by woodworkers to mean the same thing. While they serve an almost similar purpose they are still different products and suitable for different wood filling projects.

Knowing the difference between a wood filler and putty is vital for every woodworker as it makes it easy to pick the right product for a project.

Wood Putty

Wood putty is also what many seasoned woodworkers and experts like to refer to as “plastic wood”. And it is one of the most common wood filling compounds in many workshops.

Wood putty is the type of filler that you apply after staining or varnishing your workpiece, and this is because most types will contain chemicals and other ingredients that can damage the raw wood.

Although the ingredients of wood putty can vary from one manufacturer to the other, all are oil-based compounds. And the primary ingredients in most as are boiled linseed oil, some calcium carbonate and a universal colorant.

It will resemble a plastic resin and will feel like soft clay when you add some water. The stiff dough texture of wood putty means that you need a putty knife to apply it.

Once dry wood putty will harden but this takes a long time or at least longer than wood filler. Some types will harden on their own while others will require you to mix in a hardening chemical to stiffen the putty.

The long drying time if the greatest shortcoming of the wood putty as it means that lighter colors can accumulate dust and darken once the patty is dry. And this can affect the appearance of the workpiece.

You can get wood putty in a variety of colors and hence making it a versatile filling agent. The many color options make it easy to find something that matches your wood stain.

Wood putty is the best filling agent for use on outdoor furniture as it not only resists shrinkage but is also less prone to the effects of the natural elements like sun and rain.

It is also more cost-effective than wood filler because it lasts longer. Even when the putty dries in the container you only need to use a little acetone to restore it.

Lastly, wood putty also has some adhesive properties and this makes it a great masking glue but it works best with oil-based finishes.

Pros

  • More cost-effective. A small container of wood putty will last for a long time which makes it a more cost-effective filling agent. Even when it dries in the bottle, a few drops of acetone is all you need to refresh it
  • Adhesive properties. Wood putty has adhesive properties and so you will not always need to use a seal. However, this will only work on the oil-based finishes.
  • Best for outdoor furniture. Unlike wood filler, putty resists shrinkage and it is more resistant to the effect of the sun and rain which makes it the best choice for your outdoor furniture.

Cons

  • Longer drying time. Most kinds of wood putty will take more time to dry than wood fillers. And the biggest disadvantage about this is that a light colored wood putty can accumulate dust and darken.

Time of application is one of the main differences between wood putty and filler. Unlike wood putty, you should apply wood filler before doing any staining or finishing on the workpiece.

The wood filler or wood grain filler is a putty-like compound made from a combination of materials such as epoxy, lacquer, clay, and polyurethane.

Although most wood fillers will come in a neutral color it is possible to add tints or dye so that it can match the colors and grain of the wood. Also, you can mix it with sawdust for a more natural look.

Wood filler is often the better option when you want to fill large holes and cracks on the workpiece. And it comes in various types which are formulated for different uses.

The latex filler is one of the common types and it is water-based for easy cleanup. Latex fillers also mix well with dyes and they will be a great choice for sealing large cracks and holes in unfinished wood.

Other types such as the epoxy and polyurethane fillers are also quite handy to have in the workshop. But you should only use epoxy fillers on an unfinished wood as they require a lot of sanding which can ruin the finish.

It is also important to note that wood filler is not expandable as it will break when the wood expands or contracts. Hence, it will not be very suitable for use on outdoor projects. Also, exposure to direct sunlight will make it shrink by drying it out.

Since wood filler lacks adhesive properties, it will be necessary to apply some seal on top of it. But, it is more versatile than wood putty and you can use it on various finishes.

Wood filler dries faster that wood putty and most types will start drying in as little as 10 minutes after application. And it will be dry completely in about 24 hours which makes it a great choice when working on a short deadline.

Pros

  • Relatively fast drying. Wood filler will stats drying about ten minutes after applications and in most instances, it should take a maximum of 24 hours only to dry completely.
  • Available in various types. There are more types of wood fillers than wood putty. From the stainable wood filler to the latex, epoxy and polyurethane types you can be confident of finding a type that suits your particular needs.
  • More versatile. Availability of wood filler in various types makes it more versatile than wood putty. And there are countless things that you can use it for when making indoor furniture. Most woodworkers tend to use putty more often than they use fillers as it is more suitable for a variety of finishes.

Cons

  • No adhesive properties. Unlike wood putty, fillers do not have adhesive properties and this means that still need to use seal on top of your filler when finishing the workpiece.
  • Not expandable. Wood fillers will not expand and they will instead break when the wood expands and contracts. Hence, it will not be ideal for use for outdoor furniture or products that will be exposed to the elements.

Bottom Line

If you are a professional woodworker or one of those hobbyists and DIYers that tackle a lot of different projects, it is a great idea to have both wood putty and wood filler in the workshop. You cannot always be sure what you will need for a particular project.

However, wood putty is slow drying and seems to work best with oil-based finishes only. Also, it has limited uses. And so, wood filler is a better choice for those that are looking for something versatile that will be useful for various projects.

Also, the relatively faster drying time gives wood filler advantage over wood putty because no one wants to waste an entire day just waiting for a filling agent to dry.

About the author

Ashley is an enthusastic woodworker and knows what materials and tools and materials are right for your job. Find out more at Woodworkingtoolkit.com

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