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As you’re finishing up your DIY project and you’re filling all those nail holes, you might begin to wonder…what’s the difference between wood filler and wood putty?
In this article, we will answer that and a few more FAQs you might have about both wood filler and wood putty. We will discuss:
- The differences between wood filler and wood putty
- What is wood filler?
- When to use wood filler
- What’s the best wood filler?
- How to use wood filler
- Can you make your own wood filler?
- What is wood putty?
- When to use wood putty
- How to use wood putty
The Differences Between Wood Filler Vs. Wood Putty
The biggest difference between wood filler and wood putty is its intended use. Wood filler hardens and can therefore be sanded. Wood putty on the other hand does not harden and cannot be sanded.
Wood filler is applied before staining, painting, or sealing a project. Wood putty is applied after your project has been stained and sealed.
In fact, you should not apply wood putty to raw wood. It is made with plastic chemicals that can react to raw wood and damage it.
The majority of wood fillers can be stained, but it’s always a good idea to check the packaging of your specific wood filler. Once you confirm that it can be stained, test out the stain on a hidden area to see how it looks. If fixing a smaller gap or hole, it should blend in pretty well, but if you are filling a much larger area, the wood filler might stick out even once stained.
Wood putty on the other hand is not designed to be stained. Instead, it is color-matched to different stains. You can also combine multiple wood putties to create a custom color that better matches your surface.
Though wood putty does not harden, it still cures over time. The overall curing time for wood putty is generally 72 hours or more whereas the dry time for most wood fillers is an hour or less.
Indoor vs. Outdoor Usage
Wood putty is generally better for outdoor projects than wood filler. Since wood putty doesn’t harden, it stays more malleable over time. Because it’s more malleable, it is better able to adjust with temperature changes that cause wood to expand and contract throughout the seasons.
If you would prefer to use a wood filler, I’d recommend Bondo Wood Filler. Though it’s not my favorite to use overall because of the strong smell and because you have to mix it yourself, it is a fantastic product for outdoor projects and will resist cracking.
What is Wood Filler?
Wood fillers are a great way to fill nail holes, deep scratches, and other imperfections.
The distinct characteristic of wood filler is that it hardens as it dries, making it sandable. Many wood fillers are also stainable and paintable.
Wood filler comes in two main varieties: solvent-based and water-based.
Water-Based Wood Filler
Water-based wood filler is the most common type of wood filler on the market today and is what I recommend for the vast majority of projects. They tend to be a lot less smelly than solvent-based wood fillers and can be easily cleaned up with soap and water. They also tend to dry in about 15 minutes, meaning you aren’t waiting too long to continue on with your project.
Solvent-Based Wood Fillers
Solvent-based wood fillers have a strong smell and generally take longer to dry than water-based wood fillers. Since they are generally made from vinyl or epoxy, you will likely need acetone (or something stronger than soap and water) to clean it up.
Solvent-based wood fillers are generally more expensive as well. The main pro of solvent-based wood fillers is that they are much better suited for outdoor projects. They are more resistant to temperature changes, humidity, and water.
What is Wood Filler Used For?
Wood filler can be used to fill a variety of different holes or gaps in your projects. Things like:
- Nail holes
- Seams/gaps between two boards that are flush with one another
- Filling gaps in mitered or beveled joints
- Deep scratches
- Knots in the wood
- Countersunk screws
- Gaps around wood plugs
- Reshaping corners or edges of boards that have been damaged
Though you can use wood filler to cover up a variety of different things, you don’t want to try to make it fix large holes or imperfections. If you’re painting your project you can get away with a little more, but if staining, a large area of wood filler will likely be pretty noticeable.
Yes, wood filler stains, but it’s not perfect. Check out this comparison of 7 different wood fillers and how well they stained on different-sized holes.
What is the Best Wood Filler?
The overall best wood filler is Minwax Stainable Wood Filler. They have a whole lot of different types, but I’d recommend their “Stainable Wood Filler” that comes in yellow packaging.
If you are looking for the best wood filler for an exterior project, I’d recommend Bondo Wood Filler. It is smellier and you have to mix it up yourself, but it is very resistant to cracking due to temperature and humidity changes.
We actually did a big wood filler experiment recently that tested out 7 popular wood fillers and how well they stained. I’d recommend reading that to see which wood filler might be best for you.
How to Use Wood Filler
STEP 1: PREP THE SURFACE
Remove any peeling paint and sand off any splintered wood pieces. Make sure the surface of the wood is clean and dry.
STEP 2: APPLY THE WOOD FILLER
Press the wood filler down into the hole or area that you are trying to fill. Apply more wood filler than needed to account for some shrinking when the wood filler dries. Yes, even when they say non-shrinking, you still want to overfill your holes.
If you have a lot of excess wood filler on your piece, you can scrape off some of the excess. You want the hole or area to be overfilled, but it doesn’t need to fan out across the entire workpiece or be super thick.
Check the packaging of your particular wood filler for guidelines, but for most wood fillers, if your hole is more than ⅛-¼” deep, you’ll need to apply multiple coats. Don’t try to fill really large and deep holes all in one coat. If you do, it’ll take a long time for the wood filler to dry (hours → days) and you’ll likely wind up needing a second coat anyway after sanding.
STEP 3: WAIT FOR IT TO DRY
The amount of time your wood filler needs to dry will depend on the type of wood filler you’re using, how large, and how deep of a hole or imperfection you’re trying to fill. Check the packaging on your wood filler for guidance.
Generally, we wait about 30 minutes before moving onto the next step.
STEP 4: SAND OFF THE EXCESS
Double-check that your wood filler is dry (it can be as simple as touching it). Then sand off all the excess. I generally use 120 or 180 grit sandpaper for this step.
When I say all the excess, I really mean all the excess. Some wood fillers will leave a brown or yellow hue around where you applied the wood filler. Sand the surrounding wood until it’s back to the original wood color.
Yes, wood filler is stainable, but it’s not magical. If the wood surrounding the wood filler is a different color than the rest, the stain won’t magically cover it up. So keep sanding!
Note: some wood fillers might react with the wood differently and leave a hue that does not seem to come off after even several minutes of sanding. We ran into this issue with the Minwax Color-Changing Wood Filler when used on oak and the Dap Plastic Wood on oak. Because of these tests, we’ve decided to not use either of these products on oak moving forward.
OPTIONAL STEP 5: APPLY MORE WOOD FILLER
If you had a large area to fill or you sand your piece down and realize you need some more wood filler, add another layer and let dry. Sand off the excess. Repeat as many times as needed.
STEP 6: PAINT OR STAIN
Once your surface is nice and smooth, you can paint or stain your surface like normal.
Can You Make Your Own Wood Filler?
Yes! You can definitely make your own wood filler instead of buying one from the store. In fact, we tested out not one, not two, but three DIY wood filler “recipes” and compared them side-by-side. Read more about DIY wood filler.
What is Wood Putty?
Similar to wood filler, wood putty can be used to fill holes and imperfections in wood. Wood putty does not harden over time, meaning it cannot be sanded after applying it.
Wood putty is to be applied after a project has already been stained and sealed.
It comes in two main varieties: jars and color sticks.
What is Wood Putty Used For?
Wood putty can be used on finished projects that are in need of a small repair. Examples of this might be:
- Nail holes
- Mitered corners that have begun separating
- Small cracks or scratches in the surface of the wood
How to Use Wood Putty
STEP 1: PICK THE RIGHT COLOR AND TEST IT OUT
Whether you’re a fan of sticks or jars, wood putty comes in a variety of color-matched colors. When picking out your wood putty, look at the packaging to see which colors that particular wood putty is designed for. Generally, it will list between 2-6 colors.
If you don’t see a color that you think will work, you can actually mix multiple colors together to create your own custom color.
Once you have your color picked out or your custom color mixed, test it on an inconspicuous place to make sure it’s a good match.
STEP 2: PREP THE SURFACE
Make sure the surface is clean and dry. Wipe it down before applying your wood putty to remove any dust that might be on the surface.
STEP 3: PUSH PUTTY INTO THE AREA YOU’RE TRYING TO FIX
I generally use my finger to press the putty into the hole or scratch, but you could also use a putty knife.
If you are using one of the putty sticks, “color” over the area while applying some pressure.
STEP 4: WIPE OFF EXCESS
Using either a scraper, a credit card, or a clean cloth, wipe off any excess wood putty that is not directly filling your hole or scratch.
There you have it! Now you know the key differences between wood filler and wood putty, when to use each one, and how to actually apply them for the best results.