Wood filler and spackle are two popular materials used to fill small gaps and holes on a variety of surfaces.
But what are the differences between wood filler vs spackle? And when should you use each one?
In this post, I’ll uncover everything you nee to know about wood filler and spackle. Let’s dig in!
In general, wood filler is used on wood surfaces while spackle is used on drywall. Wood filler and spackle both dry in under two hours, but wood filler shrinks as it dries while spackle doesn’t. Spackle is easy to paint but it can’t be stained as easily, whereas wood filler can be painted and stained. Both are generally easy to sand, but spackle is more versatile, as it can be used with more materials.
Differences Between Wood Filler and Spackle
When it comes to drying time, spackle and wood filler are about the same. That is, it takes wood filler and spackle about one to two hours to dry.
But with either substance, it’s best to wait at least 24 hours before sanding, staining, or painting. After all, you don’t want to start sanding wood filler or spackle too early, as this will clog your sandpaper, cause a mess, and make it so you need to fill cracks and holes again.
The time it takes wood filler and spackle to dry is influenced by a variety of factors, such as temperature, humidity, method of application, and the material being used.
You can expedite the drying process with either substance by using a hairdryer, heat gun, or direct sunlight.
Wood filler often shrinks, whereas spackle doesn’t.
The main reason why wood filler shrinks is because it gets absorbed into the wood’s pores. So if you’re filling small cracks with wood filler, it’s OK to get some filler on the surrounding wood, as chances are it’ll shrink before drying, leaving no trace of excess filler.
Spackle’s shrink-resistant nature comes from it being lightweight.
But because spackle is shrink-resistant, you need to be precise when applying it. This is especially true if you’re using spackle that includes epoxy resins, as excess spackle of this kind is hard to remove and can prevent you from achieving a flat surface.
In truth, some spackles’ present a bit of a challenge when it comes to sanding, but most of them are easy to sand. The same can be said for wood filler, as typically wood filler is easy to sand, with the exceptions being more natural versions.
If you’re dealing with a tougher wood filler, just use an orbital sander instead of sanding by hand.
But it’s best to refrain from using this tool when sanding spackle, as it’ll be too powerful and probably prevent you from achieving a smooth surface.
When applying wood filler, keep sanding in mind. That is, use as little as possible so you don’t need to do a ton of sanding later on.
You can be more liberal when applying spackle, as this is easy to remove later (with wax filler sticks) before sanding.
Painting & Finishing
Often, when woodworkers consider wood filler vs spackle, painting and staining come to mind immediately.
Spackle is paintable but not stainable. Wood filler can be painted and stained, but there are some limitations.
Sometimes, stain has a hard time setting in wood filler, and paint doesn’t always adhere well to wood filler.
Plus, if you’re using water-based wood filler, there’s a chance the stain will discolor the filler and cause it to sick out like a sore thumb.
Spackle is easy to paint, and paint adheres to it well because of its makeup.
The reason why spackle can’t be stained is because it doesn’t have pores to absorb stain.
What is Wood Filler?
Most wood fillers combine fine wood dust with some kind of hardening resin, like varnish, lacquer, latex, linseed oil, or epoxy. Other wood fillers include gypsum, attapulgite (a fibrous clay mineral), or limestone, in place of wood dust, along with a solvent or water-based hardening resin.
Wood filler takes 30 minutes to an hour to dry, and once it’s hardened it can be sanded smooth. Most would fillers can be stained at this point too, though some wood fillers don’t stain as well as others.
Specifically, wood fillers that are made with wood fibers are easier to stain than the mineral-based wood fillers, in large part because fibers-based wood fillers are more porous.
Types of Wood Filler
Latex Wood Filler
Latex wood fillers come in a range of colors, and usually they’re applied to wood that’s been treated.
Applying latex wood filler and sanding it are both easy, but it isn’t the strongest wood filler.
You can fill holes that are a half-inch or smaller, but anything larger should be filled with a stronger wood filler.
Epoxy Wood Fillers
Epoxy wood filler is much stronger, but it’s harder to sand. It can be applied to both natural and treated wood, and it’s mainly used for durability.
Epoxy wood filler isn’t the most attractive filler, but its appearance can be improved, or at least masked, with either stain or paint.
DAP’s Plastic Wood
Another popular wood filler is DAP’s Plastic Wood.
With this wood filler, you don’t have to guess when it’s dry, because it’s pink when first applied but slowly turns the color of wood as it dries.
You can apply this kind of wood filler with a putty knife, and it’s so easy to spread that it can even be used on vertical surfaces.
Along with being easy to sand, it’s also stainable, paintable, shrink-resistant, and a lot stronger than most other wood fillers.
Water-Based Wood Fillers
Wood fillers are often broken down into two categories: water-based and oil-based.
The main ingredient in water-based wood filler is usually wood dust or gypsum, and water—as the name implies—is the solvent used.
Water-based wood fillers are thinner, quick-drying, and easier to apply, but they’re not as strong.
Because they’re not as durable, it’s best to use them only on interior wood surfaces.
This kind of wood filler is great at filling small holes and cracks, and since it doesn’t have a high amount of volatile organic compounds (VOC) it’s a more eco-friendly option.
Oil-Based Wood Fillers
Oil-based wood fillers are thicker and more durable, but they’re less eco-friendly due to their high concentration of VOCs.
Epoxy and vinyl wood fillers are two popular oil-based options, and they’re mainly used outside because they can withstand the elements.
But if you have to fill a lot of small holes, it’s best to go with water-based over oil-based wood filler, as using a lot of the latter substance leads to a mess more than anything else.
When to Use Wood Filler
Wood filler is usually applied with a putty knife, and it’s mainly used to fill holes, small cracks, gouges, and minor defects in floors, windows, doors, tabletops, and other wood surfaces.
Filling Nail Holes
If your wooden surface is rife with nail holes or screw holes, wood filler can be used to cover up the holes. It’s easy to fill small holes with wood filler, and you don’t have to worry too much about over filling holes, as wood filler shrinks as it dries. You can find the best wood filler for screw holes for more info!
Filling Gouges, Cracks & Other Imperfections
Nail holes aren’t the only things that can make a wood surface look unsightly. Perhaps your wood has been dinged, dented, and gouged too. Well, in all these cases you can apply wood filler to get a smoother, more visually appealing surface.
Wood filler can be used to fill gaps too, particularly those around joints. In this case, the wood filler reinforces the joint and ensures a smoother overall surface.
Filling Large Gaps
Sometimes you might have larger cracks or gaps in your wood that you need filled. There are many wood fillers for large holes that can perfectly hide these gaps.
Wood Filler vs Wood Putty
The terms “wood filler” and “wood putty” are often used interchangeably, but these are different substances.
Both substances can be used to repair holes in wood, but they’re mainly different in how they work. Wood filler hardens after it’s been absorbed by wood pores, whereas wood putty hardens above the wood’s surface.
But wood putty is easier to mold, so filling cracks with it is a breeze. And because it doesn’t harden completely, like various wood fillers, it can withstand fluctuating temperatures and humidity.
You can check out my full wood putty vs wood filler comparison for more info!
What is Spackle?
Spackle is comprised of gypsum and binder, and there are several different kinds of spackle, each one being good for a specific purpose.
Spackle is often compared to drywall mud, and its consistency resembles toothpaste.
Like wood filler, spackle is used to fill nail holes, small cracks, and minor defects, but whereas wood filler is used with wood and wood-based materials, spackle is mainly used with plaster.
That said, there are times when plaster can be used to make a wood surface smoother, but more on that later.
Types of Spackle
Lightweight spackle is made with sodium silicate and an adhesive, and it’s used to repair holes, cracks, and other small defects. It’s often used as a quick but temporary fix, and it’s hard to sand smooth.
Standard spackle, otherwise known as all-purpose spackle, is made of gypsum. It resembles drywall mud in numerous respects, and it’s used to fill deeper holes, gouges, and cracks in drywall.
Acrylic spackle is both flexible and durable, and usually it’s applied to plaster, brick, drywall, stone, and wood. Because of its many attractive properties, this is a preferred spackle for outdoor use.
Vinyl -based spackle is great for filling cracks and holes in plaster and drywall that are no more than 3/4 of an inch deep. But because you need to apply multiple layers, the application process is longer.
Still, this spackle is easy to sand smooth and durable, so like acrylic spackle, it can be used outdoors.
Just like there’s epoxy wood filler, there’s epoxy spackle. An oil-based spackle, it can be used to repair holes, cracks, gouges, and other imperfections in plaster and drywall. It too can be used outside because of its strength.
When to Use Spackle
Patching Drywall & Plaster
Spackle is mainly used to fix drywall and plaster before painting.
Specifically, it can be put in nail holes, dents, gouges, cracks, and joints to make a smoother overall surface before painting.
Fixing Door Frames & Window Treatments
Spackle can also be applied to door frames and window treatments to patch them up. But before you use spackle in this way, you need to check the spackle you’re using to see if it can be applied like this.
Need some help applying spackle? Check out the video below!
Spackle vs Joint Compound
Joint compound is another common product to patch drywall, but there are a few differences to keep in mind.
Spackle is harder to spread than joint compound, but where it lacks in spreadability it makes up for in durability.
Once dry, spackle is crack- and shrink-resistant, and it can also withstand fluctuations in both temperature and humidity.
But its strength and durability come at a cost, and generally speaking spackle is more expensive than drywall compound.
It’s best to use spackle on small projects. Repairing holes with spackle on large projects can get expensive fast.
For reference, a small tub of spackle should last you several months or a year, provided you don’t have to use it often.
Wood Filler or Spackle for Trim?
The answer to this question depends on what the trim is made of. If it’s wood trim, it’s best to use wood filler or wood putty. Plaster trim, on the other hand, should be fixed with spackle.
You have a better chance of achieving a smooth finish if you use wood filler or wood putty with wood and wood-based materials, mainly because these fillers, like the woods they’re used on, contain cellulose.
In the same sense, it’s easy for spackle to form smooth, flat surfaces with plaster and drywall because the components used to make it are also in these materials.
Spackle or Wood Filler for MDF?
In the case of medium-density fiberboard (MDF), you should use wood filler instead of spackle to address blemishes in the surface.
MDF is usually rife with holes, cracks, and other minor imperfections, so it’s best to use an inexpensive water-based wood filler when you have to repair it.
Medium-density fiberboard isn’t the strongest material, so there’s no point in filling holes with a strong, oil-based wood filler.
You wouldn’t use spackle with MDF because this is a wood-based material. Of course, you could use spackle to plug a small crack or nail hole in MDF, but the final seal would look unsightly and most likely be unreliable.
Can you use Spackle as Wood Filler?
Although it’s technically possible to use spackle as wood filler, you shouldn’t do this unless you have no access to traditional wood fillers or wood putty.
Spackle works best with drywall, plaster, stone, and similar materials.
That said, in some ways spackle resembles gypsum-based wood filler, so you could get away with using this in a situation where this kind of wood filler would work.
But if your goal is to achieve a smooth, uniform wood finish, it’s best to go with wood filler over spackle.
So which is superior when it comes to wood filler vs spackle? Well, the answer is pretty simple: wood filler is great for repairing natural wood and wood-based materials while spackle is great for repairing drywall, plaster, stone, and similar materials.
These substances aren’t all that different, but whereas spackle can be used with wood surfaces in a desperate situation, it’s nearly impossible to think of a reason that justifies applying wood filler to drywall or plaster.