do you have to seal wood filler?

Wood filler is a much-needed staple in most woodworkers’ toolboxes. It’s an easy, fast fix for small cracks, dents, and holes. But what about large gaps? Do you need to seal the wood filler after applying it?

Do I need to seal wood filler?

Sealer is a necessary step for wood filler because it protects the material from moisture and will help to keep it from taking on any kind of permanent color that would be difficult to remove later.

If you don’t seal your wood filler, the product may absorb some of the stain on top of it. Then when you paint over that area, you’ll have a lighter patch in an otherwise consistent shade of color.

More importantly though, if there are gaps between your wood filler and its surrounding surface (so called “bleed-through”), they’ll show through easier without a protective layer over them.

How do you protect wood filler?

  • You can protect your wood filler with a stain. This is an easy, affordable way to keep your patch from showing through the finished project. Many stains are water-based and do not require any mixing; simply follow the instructions on the label for application. If you choose to use traditional oil-based stains (such as those used on kitchen cabinets), they will be more effective at covering up existing patches but may require more maintenance after applying them.
  • You can also opt for a varnish or paint finish over your patch instead of staining it. Once again, this depends on how much time and money you want to spend protecting your patch from wear and tear once it’s installed in your project—varnishes tend to last longer than paints but are harder to apply evenly across uneven surfaces like plywood due to their thick consistency; however, both types of finishes will provide some protection from wear while also allowing color variations found throughout natural wood species such as hickory or oak trees!
  • Sealers offer another option if you’re looking for something less permanent than stain or varnish that won’t interfere with future renovations around your home—they’re similar

Is wood filler waterproof?

Wood filler is not waterproof. It needs to be sealed, which can be done with paint or varnish, polyurethane, epoxy or shellac.

Does wood filler harden like wood?

The short answer is no, wood filler does not harden like wood.

Wood filler is a polymer which means it’s made from plastic (or more specifically, petroleum). The main difference between polymers and real wood is that the particles in polymers are much larger than those found in natural materials.

These larger particles mean that the polymer will never shrink or swell like real wood does when exposed to changes in moisture content. And without this variance, there’s no grain structure!

What happens if you use wood filler without a hardener?

If you use wood filler without a hardener, it will not harden like wood. It will remain soft and sticky, which makes it easy to sand but also much more likely to stain the surface of your project.

Wood filler is most commonly used to cover small scratches in furniture or plastic models.

It’s not waterproof and won’t last long outdoors unless you seal it with an exterior finish after using a hardener to make sure it’s hardened completely before placing outside again.

How long does wood filler take to harden?

It depends on the type of wood filler you’re using. Some products can be sanded in a few hours, while others take days to fully cure.

Some types of wood filler can be painted after 24 hours and others need to cure longer—it will depend on what the manufacturer recommends for your specific product.

It’s always a good idea to read through the instructions before starting any project!

Why does my wood filler keep cracking?

One of the most common reasons for wood filler to crack is moisture. The wood in your walls may have become swollen from excessive humidity, causing the wallboard to expand and then contract as it dries out.

This can cause the filler to crack along its edges or in a grid pattern that resembles a honeycomb formation.

If your wood filler is not dry enough, it will shrink when installed, leaving some spaces between the boards that need filling in order for them to be flat and level with one another.

This can leave gaps between nails or screws that hold things together on either side of where you applied your wood filler (like paneling).

If this happens often enough with certain parts of an object like cabinets or furniture frames, it will eventually cause these joints’ structural integrity to fail entirely–and therefore make those parts unusable!

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

So, what’s the difference? In general, putty is softer and easier to work with than filler. Putty is designed to fill small holes and cracks in wood—for example, if you have some damage on your baseboards or around the edges of a cabinet.

Filler comes in larger containers and is used to fill larger areas like holes from a nail popping through the wood or large scratches on furniture surfaces.


In short, yes you do have to seal wood filler. Wood filler is not a miracle worker that can be left exposed to dirt and moisture without causing damage.

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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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