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

Published September 9, 2023

If you’re not a seasoned woodworker, wood putty and wood filler may seem similar. And we wouldn’t fault you for that.

In the world of woodworking, both are used to fill holes and repair damages. But while many use them interchangeably, they are actually different. Distinguishing one from the other will help you avoid the pitfalls of countless others before you.

So, what is the difference between wood putty and wood filler?

There are many. But, one significant difference between wood putty and wood filler is its composition. The former is made of plastic chemicals and oil-based compounds. While the latter consists of wood particles and fibers mixed with a binding agent. This is why wood filler hardens while wood putty doesn’t.

Wood filler is applied to repair the wood from the inside. Because it hardens, it helps the wood maintain its integrity. While wood putty is usually used only after the finishings are done since it contains chemicals that may damage the wood.

Most manufacturers also produce wood putty in various colors matching wood stains. So, it usually just blends in with the wood. The same cannot be said for wood filters, which usually come in a single color.

When to Use Wood Putty

Because it doesn’t harden, it contracts and expands with the wood. This makes it ideal for outdoor wood projects.

We all know that changes in temperature and humidity can make wood expand and contract. Since they are exposed to all kinds of weather, outdoor wood structures are much more prone to such. If you use wood filler, it will break when the wood expands or contracts. Wood putty, however, will remain in place even if the wood gets twisted.

Most woodworkers also use wood putty for minor repairs and to cover minor imperfections. This includes nail holes, small blemishes, and minor joint mismatches.

When to Use Wood Filler

A wood filler will cover significant damage on an indoor wooden structure.

Since indoor structures are protected from the elements, they don’t expand or contract dramatically. Plus, the wood filler dries faster than wood putty. It also contains primarily organic materials, so applying them in large quantities won’t cause harm to your wood.

Unlike wood putty, though, you might have a hard time matching it with a particular wood stain. So, it’s better to take a small portion of the filler first and apply some wood stain until it matches your wood’s color. Use that filler-stain proportion to determine how much wood stain you should put on it.

Pros and Cons of Wood Putty

Pros

1. Sandable

Wood putty can be easily sanded, allowing for a smooth and seamless finish.

2. Paint or stainable

Wood putty can be painted or stained to match the surrounding wood, making it blend in seamlessly.

3. Hardens as it cures

Once dry, wood putty hardens and becomes durable, providing a long-lasting repair.

4. Quick drying

Wood putty dries relatively quickly, reducing the wait time for completing projects.

5. Tintable

Wood putty can be tinted before use. This allows the customization and achieving the desired color.

Cons

1. Less suitable for unfinished wood

Wood putty is better suited for finished surfaces, as it may not adhere as effectively to unfinished wood.

2. Limited flexibility

Once hardened, wood putty is not flexible. This may impact its suitability for specific applications.

3. Not ideal for exterior use

While wood putty can be used to repair damaged interior walls, it is generally not recommended for exterior repairs. This is due to its lack of weather resistance.

Pros and Cons of Wood Filler

Pros

1. Versatile

Wood filler can be used on various types of wood, including hardwoods and softwoods. This makes it suitable for different woodworking projects.

2. Easy to use

The wood filler typically comes in a paste-like form that is easy to apply and manipulate. It allows for the precise filling of voids.

3. Seamless finish

Once dry, wood filler can be sanded, stained, or painted to match the surrounding wood, creating a seamless and uniform appearance.

4. Strengthens weak spots

Wood filler can reinforce weak or damaged areas, improving structural integrity.

5. Affordable

Compared to replacing or repairing damaged wood, wood filler is often cost-effective.

Cons

1. Limited flexibility

Once dried and hardened, wood filler becomes rigid and lacks flexibility. This makes it prone to cracking or separating if subjected to significant movement or stress.

2. Not suitable for load-bearing applications

While wood filler is excellent for cosmetic repairs, it is not designed to bear heavy loads. It is best used for non-structural applications.

3. Limited weather resistance

Some wood fillers may not be suitable for outdoor use due to their vulnerability to moisture, UV exposure, and temperature changes. Ensure to choose the suitable wood filler for the intended application.

4. Difficult to remove

If you need to remove wood filler, it can be challenging without damaging the wood surface, especially if it has been stained or painted over.

Wood Putty vs. Wood Filler: A Comparison

Uses

Wood filler repairs dents, gouges, and scratches in unfinished furniture. It is also used to fix holes in wood flooring and cover cracks in unfinished woodwork. It is best suited for non-structural repairs.

Wood putty is typically used for filling imperfections in finished wood surfaces. It is for surfaces where sanding and staining are required to achieve a seamless finish.

Drying Time

Wood filler can take varying amounts of time to dry, depending on the brand and formulation. Some may dry within minutes, while others may need several hours or overnight drying.

Wood putty generally dries faster than wood filler. It can be ready for sanding and finishing within a shorter timeframe.

Price

The price of wood filler and wood putty can vary based on the product’s brand, quantity, and quality. Generally, wood putty tends to be more expensive than wood filler.

Sandability

Both wood filler and wood putty can be sanded once dried. But, wood filler is often easier to sand due to its composition. It typically includes wood fibers or sawdust. Wood putty, a more pliable mixture of chemicals and colorants, may be slightly more challenging to sand.