Wood Filler Vs Wood Putty – The Difference

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We had just installed our luxury vinyl plank flooring and I had borrowed my brother’s finish nailer to install shoe molding. Now I just needed to fill those nail holes. 

Should I use wood filler or wood putty? Growing up, my dad used the terms interchangeably. There are some companies that still use both wood putty and wood filler interchangeably. Both are used to fill holes.

However, knowing the difference empowers you to spend less time standing confused in the aisle at Lowes and more time working on your project. 

I’ll give you a quick hint: It turns out that wood putty is good for tiny holes and wood filler is best for large holes.  Also, you stain wood filler, but you color match wood putty.

Ultimately, if you are going to paint the wood, your choice won’t matter too much. For staining, I would choose a stainable wood filler. 

 Best Practice: Over-apply the filler or wood putty and then sand down after it is dry. Beware of shrinkage! 

Here is how to get the right one to solve the cosmetic problems in your wood.

See Related: Dry Wood Fast Without A Kiln

Main Differences Between Wood Putty Vs. Wood Filler

Wood filler and wood putty are different. The wood filler also contains small particles of sawdust or wood fibers while wood putty is generally just a polyurethane binder that fills smalls holes but does not harden. 

With wood filler, you can fill larger gaps, and then sand it down for a smooth finish. It is handy for restoring overly damaged wood. Some clever Tik-Tok accounts have started a hilarious channel showing them “fixing things with Ramen”. These videos are a testament to the hardness of wood filler. 

Wood putty doesn’t harden to make it flexible for future wood movement. This makes it much cleaner to work with when filling small nail holes. It also makes it easier to clean up if dropped on the floor. 

Exterior wood fillers can also be used outside. They contain UV-protective elements to help them survive sunlight and harsh external conditions.

Wood Filler Types

Wood filler is a good choice for restoration when you have major imperfections in the wood. Most wood fillers are both sandable and stainable.

In the old days, you’d just use sawdust and glue to fill gaps in the wood. The process was messy, and PVA glue is hard as a rock and difficult to sand (If you need a custom wood filler solution, this method still works). 

Minwax probably does the most to create a distinction between the two types of products. Their wood filler is stainable and rated for exterior use. It goes in well, and I find it to be a pleasure to use. It also seems to hold up well in my house where we have a lot of kids running around. 

DAP calls their wood filler “plastic wood”. That is a good descriptor. Once cured, it can be sanded and painted or stained, much like real wood (it will likely have a different color than the surrounding wood if stained, so color matching takes some patience).

However, for wood that is rotten, and that you need to patch to get it through a few more years, you might look at the old glue and sawdust method or JB Weld’s quick wood. Bondo also makes extremely durable products for extreme wood damage. 

These more durable wood fillers are a 2-part system that requires mixing with a hardener and they don’t go on as smoothly. However, they generally hold up well. 

Wood fillers will not stop a crack from spreading unless you use an epoxy-based filler. Epoxy-based fillers can help slow cracking. 

Here are the 2 different types of wood filler. 

Polyurethane Wood Filler?

Ya’ll can tear me apart in the comment section, but I can’t say that I’ve seen a wood filler that I would classify as “polyurethane-based”. 

There are some threads with folks trying to mix sawdust and poly, but I’d recommend sticking to the PVA glue and sawdust method described above. 

Other folks have asked about applying polyurethane over wood putty. You are supposed to apply wood putty after the stain or poly has been applied. Reversing that can cause more discoloration of the putty.

Water Based vs. Solvent Wood Fillers

Either can be used, however, there are a couple of differences: 

Water-based are going to use cellulose, gypsum, or wood fibers and they have the advantage of a lower odor and lower volatile organic compound (VOC) emissions. They dry in 15 minutes and clean up with soap and water. 

Solvent-based fillers contain vinyl or epoxy and are much more durable for exterior use and large, deep holes. They require more time to dry and you will need a solvent such as acetone for cleanup. 

Wood Filler Use:

You have thick or thin consistencies. When trying to repair a large hole on a rotten porch column, you will want a thick filler. Conversely, smoothing a large number of holes can easily be done with a thin pancake-batter consistency filler.

In a pinch, you can thin some of the thicker wood fillers, but you’ll get the best results out of matching the right filler to the job.  

Overall, it is more versatile for filling holes. Wood fillers work great for fixing cracks in unfinished wood prior to staining. It can also be used on raw wood. Wood filler hardens to create a more durable bond.

Porous Surfaces

Grain wood fillers create a mirror-flat finish. Shellac, Lacquer, and Varnish with silica mixed in are generally used to finish wooden furniture as a grain filler. It easily applies with a putty knife.

Aquacoat is leading the way in this industry, with a wide variety of options based on the type of work you are doing. 

Generally, you will use one or two coats of a grain filler — just enough to hold up to sanding — and then will stain and seal over that. 

Big Holes

Have you seen the amazing resin table art that folks are doing? Two-part Epoxy is your best choice to fill large holes. Epoxy will seal the hole and stop further spread.

Dig our rotten wood and smooth the hole well with sandpaper before applying.  

When Not To Use

Wood fillers can be used in any condition. Exterior conditions may cause the filler to not hold up for as many years due to wood’s natural tendency to shrink and expand with the weather.

Wood Putty Types

I find wood putty very pleasant to work with. 

It feels like soft clay and is easily stuffed into small holes. 

It is most commonly used on finished wood projects and you purchase the putty color to approximate the finished color. 

Apply the putty after the finish has been applied. 

The thing about wood putty is that it is best for smaller holes. It’s generally not going to hold up as well if you use to fill in large areas of missing wood.  It is great for trim work or on hardwood floors.

Minwax wood putty is my personal favorite. 

FAQs About Wood Filler vs Wood Putty

What type of wood filler is best for large holes or gaps?

For large holes and gaps, I recommend using an epoxy-based wood filler that can help tie the wood together and slow the spread of damage. 

We did a home remodel 15 years ago where we put in defective wood flooring. We filled the knotholes and gaps with a stainable 2-part epoxy and stained it with a basic lacquer. It has held up well through multiple renters. 

Will wood glue work as a substitute for wood filler?

Yes. One of the oldest methods is to fill the crack with glue and then mix an ample amount of sawdust from your project into it, providing a perfect match.

How long will wood filler last?

Generally, I’ve noticed exterior wood filler jobs lasting about 5 years. 

Interior jobs seem to last forever. 

Is wood putty as strong as wood?

No, it is not as strong. Wood putty is only as strong as the chemical binder. Just become some wood putties can create a hard, tight, fill, the finished product is not stronger than an undamaged, un-filled piece of wood. 

What is the difference between wood filler and spackle?

The difference is that wood fillers contain real sawdust, while wood putty tends to be made from chemical compounds.

When choosing one based on use-type, you generally will use wood putty for small holes. For small holes you can — at least temporarily — get away with using drywall spackle. It will give you a smooth finish and holds up well. 

The problem I’ve had is that it becomes crumbly over time.  We did this in a highly trafficked hallway and had to redo the job with wood putty. 

Be aware that spackle does not take stain. 

Is car body filler the same as wood filler

Auto body filler is not the same, but you can certainly use it as a wood filler. This tends to work best in a climate-controlled interior where the wood is not constantly expanding and contracting. 

When used on the exterior wood, these auto body fillers will pull away from the wood and prematurely fail.

Can I use wood putty to fill wood?

You can certainly use putty to fill wood. Putty often comes in a color match that lets you get a close match to the finished wood. However, for deep gouges and dents, I find wood filler to provide a better finish for sanding and painting. 

What Type of Exterior Wood Filler for a Railing Is Paintable?

When repairing a weather-damaged porch, you need to choose the most durable, 2-part epoxy wood filler. 

This will likely take 1-2 days to dry. 

Dig out the rot, sand down the wood, and get to the good wood underneath. And then you can fill the damaged area. After letting it cure, it can be sanded and painted and will hold up to constant handling. 

 

Zachary Drumm

Hey! My name is Zachary Drumm! This site allows me to test new tools, piddle around in the garage, and share the insights I get from flipping cars and houses. When it comes to tools, home improvement, and being a “shade tree mechanic,” you’ve come to the right spot. If I’m not in the garage creating content, you’ll find me outside, running, canoeing, and traveling. My goal is to empower more people to be self-sufficient.

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