Last Updated on May 12, 2023 by Ernest Godia
Wood isn’t perfect. Wood surfaces often have dents, cracks, nail holes, scratches, and other imperfections. These undesirable features on the wood don’t make it less valuable, as you can fix them and make good use of the wood.
Wood putty and wood filler are solutions you can use to fix these surface imperfections and improve the wood’s aesthetics. But how long does wood putty take to dry? And does wood putty harden to resemble natural wood?
This article looks at wood putty and wood filler, their drying behavior, and when to use each product for the best results.
Does Wood Putty Harden?
No, wood putty dries but does not harden. Even in its dry state, the product remains flexible to contract and expand with the wood as humidity and temperature change. Due to its flexibility and non-hardening quality, wood putty is ideal for fixing minor issues on outdoor wood surfaces exposed to extreme weather changes.
However, adding a suitable hardener to wood putty can induce wood putty hardening and make it dry faster and hard. Wood putty with a hardener is more solid and less flexible than standard wood putty when dry.
How long does it take for wood putty to dry?
Wood putty takes approximately 2-8 hours to dry. However, you can accelerate the drying time by applying a hardener or subjecting it to optimal drying conditions.
The drying time depends on the following factors:
- The size of the hole filled by the putty
- The amount of wood putty used
- The type of wood putty
- Temperature
- Humidity
The wood putty in large diameter holes will take longer to dry than in smaller cavities. In addition, you might have to add a second layer to areas with more significant imperfections for maximum coverage, which may take longer to dry.
Temperature and humidity influence the drying time of wood putty. The less wood putty used, the less time it will take to dry, and vice versa. Water-based wood putty takes 30 minutes to dry, while petroleum-based putty takes 24 hours.
What is Wood Putty?
Wood putty or plastic wood is a paste of petroleum-based and plastic-based solvents used to fill and mend imperfections on finished wood. You apply wood putty on nail holes, nicks, or gouges on the wood surface. Wood putty doesn’t shrink, harden or crack.
Since wood putty is used only on stained or finished wood, it is available in various tones to match the color of the finished wood you are working on. The downside to wood putty is you can’t sand, paint, or stain over it.
However, you can apply a suitable topcoat like polyurethane over wood putty to match the sheen of the surrounding wood surface.
Common Types of Wood Putty
Wood putty can be water (acrylic) based or oil-based. Since wood putty is used on finished wood, it is best to use water-based wood putty on wood with a water-based finish and oil-based putty on wood with an oil- or solvent-based finish.
Water-based wood putty drying time
Water-based wood putty takes approximately 24 hours to completely dry. Apply the water-based wood putty with a putty knife and wipe off the excess before letting it dry.
The product is available in several colors, and if none blends with your wood surface, custom tint the putty to the desired color.
Since it is water-based, this putty cleans up quickly and is suitable for indoor wood.
Petroleum-based wood putty drying time
PA petroleum-based wood putty has a drying time of about 48 hours, about twice that of water-based putty. It is an excellent option if you intend to have an oil-based topcoat because water and oil don’t mix.
Petroleum based-wood putty can work on outdoor wood surfaces as it tolerates the elements better than water-based putty. Also, it shrinks less as it dries, thus a good choice when filling larger gaps.
Advantages of Wood Putty’s Non-hardening Quality
Let’s look into the benefits of wood putty’s non-hardening nature:
- Wood putty expands and contracts with environmental changes, including temperature and humidity. This allows it to remain intact and not break away from the wood as the latter expands and contracts.
- Due to its flexibility, wood putty changes shape as the wood does. This response prevents it from damaging the wood as a rigid substance would.
- Wood putty’s non-hardening quality also prevents it from cracking and forming unsightly marks on the wood surface.
What is Wood Filler?
Wood filler is a paste made of solid wood byproducts such as sawdust suspended in binders like glue, varnish, or lacquer and can infuse and adhere to wood fibers. Wood filler dries rock solid and is ideal for indoor use.
Wood fillers can be water-based or solvent-based.
Water-based wood filler
The water-based wood filler comprises wood fibers mixed in wood glue and other additives. It is the most common wood filler type and cleans up easily with water and soap because it is water-based.
Water-based filler is not ideal for outdoor projects because water exposure can rehydrate and turn it back to paste form.
Water-based wood fillers also shrink while drying. So always overfill the holes to avoid ending up with a divot after the water evaporates and the filler dries.
Consider using this product on indoor projects that you intend to paint, as the paint coat protects it, making it waterproof.
Solvent-based wood filler
Solvent-based wood fillers contain wood fibers or sawdust mixed in solvent-based compounds and binders, making them highly durable and robust when dry. These wood fillers are advertised to be stronger than actual wood and are ideal for large gaps.
Thanks to solvent-based wood filler’s incredible strength, you can place anchors and nails within it when dry. The durability also makes the product suitable for exterior wood projects.
It’s best to use wood fillers when:
- Fixing gouges, cracks, or dents on unfinished wood surfaces.
- Molding or shaping the edges of tabletops, cabinets, or countertops.
- Filling gaps on flooring boards.
How long does it take for wood filler to dry?
Wood filler dries and hardens in about 30 minutes to one hour. However, the specific drying time usually depends on the type of wood filler used. Applying the product in optimal conditions can ensure it dries and hardens enough to be sanded in 30 minutes.
Some wood fillers dry pretty hard, making them challenging to sand. When using such wood fillers, consider sanding them with power sanders like an oscillating sander with a medium and then fine 180-220-grit sandpaper.
Differences Between Wood Putty and Wood Filler
While wood putty and wood filler have similar uses, they are different products suitable for different projects. Here is a detailed comparison of wood putty and wood filler.
1. Wood putty never hardens, while wood filler hardens within minutes
Wood filler combines wood fibers suspended in a hardening resin solution, making it pliable while wet but rock-hard when dry.
Wood filler hardens pretty fast after application, and as it dries, the filler can crack and shrink. Moisture and heat predispose the wood filler to expand and contract, so it’s best for indoor use unless explicitly formulated for exterior projects.
The chemical composition of wood putty doesn’t allow it to harden. It eventually dries and cures but remains flexible.
2. Wood putty is used on finished wood surfaces, while the wood filler is best on unfinished surfaces.
Wood putty is made of plastic and oil-based compounds like calcium carbonate, boiled linseed oil, and universal colorants. The chemical composition of wood putty damages the wood fibers when exposed to unfinished wood.
If you have to apply wood putty on raw wood, it is best that you lay a coat of stain to act as a protective barrier between the putty and the wood. To avoid all that, use wood filler on raw wood and wood putty on finished wood.
3. Wood filler is sandable and paintable, while the wood putty is available in wood tones
Wood filler dries relatively fast, and you can gently sand it to smooth the surface. The solid wood fibers or sawdust in wood fillers give them a texture that allows for sanding and refinishing.
You can paint or apply wood stain over wood filler. Most brands of wood filler accept paint, but before staining, test it first on some scrap wood to confirm it works.
Some wood fillers are blotch-prone and will form patches of color when stained over, so it is best to paint rather than stain over such fillers.
Wood putty is tricky to sand over or stain as it does not harden when dry. But you can apply a suitable finish, such as polyurethane, over a fully cured wood putty. Wood putty comes in various colors to match the piece you are working on.
4. Wood putty is suitable for outdoor use, and wood filler is best used indoors.
Most wood putty brands are weatherproof and great for outdoor projects. The product’s flexibility means it changes with changes in temperature and humidity, letting it remain unaffected by weather changes.
On the other hand, wood filler dries hard, making it crack when exposed to fluctuating temperatures and humidity.
Wood filler is a better choice for indoor surfaces. However, some brands make wood fillers for outdoor use. Always read the label for the specific use instructions.
5. Wood filler dries relatively faster than wood putty
Wood filler is dry to the touch within 30 minutes and completely dry in an hour or two. Wood putty takes about 2-8 hours to dry. In addition, wood putty cures very slowly.
How To Apply Wood Putty?
Here is how to fill wood surfaces with wood putty:
What you’ll need
- Putty knife
- Wood putty
- Sandpaper
- Wood stain
- Tack cloth
- Primer
- Mineral spirits or acetone for petroleum-based filler
STEP 1: Select the right color and test it
Buy wood putty that dries in a similar color to the wood surface. The idea is to ensure the wood putty used matches the wood color that you use it on. Test the putty on scrap wood before applying it to your project.
STEP 2: Prepare the wood surface
Ensure the wood surface is clean and the gaps, cracks, and nail holes are dirt free. Applying wood putty over particles or dust permanently seals them on the wood.
STEP 3: Apply the putty into the intended area
Wood putty comes in ready-to-use cans. Open and scoop a workable amount with a putty knife. Place it in the intended gaps or over the blemished wood surface and even it out with the putty knife.
You can also fill any nail holes or cracks on the wood surface with your fingers before using the putty knife to even out the putty.
STEP 4: Scrape off the excess
Scrape off the excess putty and ensure the wood surface is visually perfect and feels smooth. Let the wood putty dry and cure.
How to Shorten the Drying Time of Wood Putty
If you are pressed for time, you may find the long drying time of wood putty a bummer. However, you can speed up the process with the methods below. Here is how to make wood putty dry faster:
Method 1: Apply in warm weather or environment
Humidity and temperatures have an impact on the drying time of wood putty. So ensure you work in warm weather with low humidity to accelerate the drying process.
If you are working on your project during the cold season, apply the wood putty and turn up your home’s heater to raise the ambient temperatures around your workstation.
Method 2: Warm the filler
Subject the wood putty to high temperature to accelerate the drying process. The best way to do this is to expose the filled wood surface to direct sunlight to dry quicker.
While at it, do not use a heating gun, as the scorching heat may soften the putty instead. This outcome may be counterproductive.
Method 3: Apply thin and even layers
Wood putty comes in paste form, and if you scoop it up and apply a thick layer, it may take forever to dry.
Apply two to three layers till the cracks and scratches are fully covered. Give each layer enough time to dry. Go for thin layers as they dry faster, and reapply if the wood surface requires more coverage after drying.
Method 4: Adequately sand the area
Smooth out the furrows in the gaps before applying the wood putty. Uneven surfaces take up more putty and require longer drying time. However, smooth, even surfaces shorten the drying time by reducing the gaps that take up the wood putty.
Method 5: Use a fan
Turn on the fan in your workspace to reduce humidity and increase air circulation, reducing the duration wood putty takes to dry.
Method 6: Use hardeners
Hardeners are a lifesaver as they enable the putty to dry faster. There are several brands and types of hardeners in the market, but epoxy resin hardeners are highly recommended.
Follow the proper procedure when mixing wood putty with a hardener, and use the correct proportions. Adding too much hardener may ruin the wood putty.
Method 7: Keep the area dry and clean
Keep the areas free from impurities and moisture, as they can slow wood putty drying. Use a damp, lint-free rag to clean the spots and let them dry before applying the wood putty.
Wood putty applied to wet and dirty gaps can take days to dry.
What Are The Uses Of Non-hardening Wood Putty?
Non-hardening wood putty helps in covering the visible imperfections on the wood surface. Wood putty fills the finished wood’s cracks, gouges, nail holes, and scratches.
Wood putty’s flexible nature makes it ideal for outdoor use as it is resistant to moisture and heat. Also, the putty fits in the imperfection and prevents further wood cracking.
In its non-hardening state, wood putty is easy to manipulate with your fingers, or use a putty knife to fix the visible blemishes on your wood surface.
When To Use Wood Putty?
Some of the instances when to use wood putty include the following:
- To repair cracks in the wood or between two wood boards, wood putty acts like glue and prevents further cracking.
- To fill dents, small holes, and nail holes on a wood surface that requires no staining.
- To fix any minor imperfections on finished wood surfaces.
- To mend imperfections on outdoor wood surfaces and furniture pieces.
Does Wood Putty Harden: FAQs
Here are straightforward answers to some of the frequently asked questions about wood putty and wood filler.
Can you make your own wood putty and wood filler?
You can make your wood filler but not wood putty. To DIY your wood filler, first make fine sawdust from the wood you intend to fill. Then, ensure the sawdust is free of impurities. Finally, mix the dust with a wood binder like wood glue, and voila! Your wood filler is ready for use.
Watch the video below on how to make your own wood filler at home.
Can you apply paint or a sealant over the wood putty?
It’s possible to apply a sealant over wood putty but not paint. The best way to go about it is to wait till the wood putty is completely dry before applying the sealant. Painting won’t work on wood putty as the product cannot be sanded to make the paint adhere to it.
How big of a gap can wood putty fill?
Wood putty can cover gaps as wide as 3/8th and larger holes require further repair. Petroleum-based wood putty can fix bigger holes than water-based wood putty.
Does non-hardening wood putty dry?
Yes, wood putty dries in approximately 2-8 hours even though it does not harden. Please reshape it before it dries, as it will be impossible to work on.
Does Wood Putty Harden: Bottom Line
Wood putty’s non-hardening characteristic is remarkable as it makes it malleable and responsive to weather changes. Wood putty is resistant to the elements, moisture, and heat, making it suitable for outdoor use.
With your busy schedule, the long drying time of wood putty may be a drawback, but this article explains different ways to speed up the process.
In the comment section below, we would love to hear about your experience working with wood putty.
Happy woodworking!
