do you need to sand wood filler?

Sanding wood filler is one of the most common questions I get from people. It’s not a complicated question, but it does have a few layers.

First, let’s talk about what sanding wood filler is and why you would want to do it. Then we’ll talk about when you can skip this step and go straight to finishing your project with paint or stain instead of sanding between coats of either product.

Do you have to sand wood filler before painting?

If you don’t want to sand it, you don’t have to. If you do want a smoother finish after applying the wood filler, then follow these steps:

  • Use a fine grit sandpaper (like 220 or 320) and sand in the direction of the grain until all rough spots are gone.
  • Wipe away any dust with a damp cloth before painting or staining your project

How do I get a smooth finish with wood filler?

Once you’ve filled the holes and dents, it’s time to smooth out your wood filler. The best way to do this is with a putty knife or other long, flat tool that will allow you to reach into all of the crevices that need smoothing.

To begin smoothing, scrape a thin layer of wood filler onto your surface and then use the smooth side of a putty knife to push it into place.

You should be able to see where any rough spots are beneath your surface; if they’re not apparent yet, don’t worry—they will become so once we start sanding!

Once you’ve covered everything with wood filler and leveled it out as best you can with an even coat, grab some sandpaper (180 grit) and start sanding until everything looks smooth!

If there are some areas where things aren’t quite level but look like they might be salvageable by only removing material from one side rather than both sides as well (this happens sometimes), go ahead!

When in doubt though: always err on the side of caution when working with power tools like circular saws or table saws because mistakes tend not to sit well with homeowners who have paid good money for their homes’ construction materials.”

Should you sand before filling holes?

If you want a smooth, even finish, then it is necessary to sand the surface before filling holes. If you’re looking for a natural look and feel that mimics the grain of the wood, however, filling first might be preferable.

You also may want to sand after filling if:

  • You want to cover large holes with filler. For example, if you have a hole in your wall where one nail went through it while hanging something up on the wall and there’s now an empty space where two pieces of drywall meet (see Figure 1), then this would require some pretty heavy-duty patching material applied over top of the old drywall and steel reinforcement behind it so as not to weaken its structural integrity too much;
  • You’re trying to make your patch look like it was made from solid wood because then all around edges would be visible rather than just inside edge being covered by another piece of wood (see Figure 2).

Does wood filler harden like wood?

No, it doesn’t. Instead, it has the consistency of plastic and is designed to be sanded down once dried.

If you don’t sand it, your project will have a lumpy finish; however, if you do leave it too long before removing the excess filler and then trying to sand it down with an orbital sander or hand sander, there’s a good chance that the filler will crack under pressure from these tools.

Why is wood filler showing through paint?

Wood filler is meant to be a gap filler, and it’s not thick enough to cover the wood. If you use too much wood filler on your project and then paint over it, the paint will peel off in places or look uneven.

The reason for this is that when you sand down your project after applying several coats of paint, there is nowhere for excess moisture from sanding to go except through the finish coat(s) of paint.

If there isn’t enough space between each layer of finish coat (and there won’t be if the wood filler is too thick), then you will end up with watermarks on top of your finished project due to peeling layers or chipping due to wear.

What’s the difference between wood filler and wood putty?

Wood filler is a more permanent solution to filling holes and cracks, while wood putty is generally used for smaller holes and cracks.

Wood putty is much thinner than wood filler, so it’s easier to work with if you’re trying to patch up a small area.

It can be smoothed over the surface of your project or applied in layers for larger patches. The downside of this method is that it doesn’t create as smooth an appearance as filling large areas with wood filler.

Wood fillers are thicker than wood putties and are meant for filling larger gaps in furniture or cabinets—essentially anywhere you’d use spackling paste (more on that later). You can also mix different shades of stain together for custom color matching!

How thick can wood filler be applied?

One of the most common questions we get from customers is “How thick can wood filler be applied?” The answer to this question depends on your project and on what type of wood filler you are using.

Because there are so many different types of wood fillers, it’s hard to say how much each one will absorb at a given thickness. Most manufacturers will give you specific instructions for applying their products.

However, there is one general rule that applies to all fillers: if the filler is too thick it won’t dry properly and may crack or crumble while drying.

The minimum recommended thickness is usually around 1/8 inch (3 mm). If you try to apply more than that without letting it sit overnight first then chances are great that some areas won’t dry properly causing them to crack later on when exposed to humidity or moisture which isn’t good for any part of your furniture!

Can you brush on wood filler?

Yes, you can brush on wood filler. However, keep in mind that brushing it on will make the surface smoother and more even than when trowel-applied. This also means that it will be harder to sand later on and clean up.

Brush-on filler is easier to control because you can use a paintbrush or roller instead of a trowel or spreader tool that requires more finesse.

It’s also faster because the material flows into small gaps better than other methods (though not as well as using an electric sander).


Wood filler can be used to fill small holes in wood and other materials. It is important that you do not use this product on any surfaces that will be exposed to moisture or water, as the filler will absorb water and expand, causing more problems than it solves.

For example, if your bathtub has a crack in it or your bathroom sink has a leaky faucet, do not use wood filler!

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Martin Flood

Martin Flood has been working in the construction industry for over 20 years as a general contractor with expertise in remodeling projects that are large or small. He has furthered his career by specializing in epoxy resin flooring, providing excellent service to both commercial and residential clients. Martin’s experience enables him to offer professional advice on how to choose the right type of project based on your needs and budget.

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