why does wood filler crack?

If you’ve ever tried to fix a hole or crack in wood with wood filler, you probably know that it doesn’t always work. But why does wood filler crack?

And what can be done about it? Thankfully, there’s an easy solution to this common problem. In this post, we’ll explore why wood filler sometimes fails and how to fix it when it does fail. We’ll also look at some alternatives that don’t involve using any adhesive at all!

Does wood filler crack over time?

Wood filler is a great choice to fill holes in wood. However, you may notice that cracks develop in the wood filler over time. This can be frustrating and a hassle to repair, but it’s easy if you know how to do it.

There are two main reasons why wood filler cracks:

  • The first reason is that the wood might have been too dry when you applied it. If it dries out before you get a chance to insert screws or nails into the area and hold them down with clamps, then any movement will cause movement around where your screw or nail was inserted into your repaired area. This movement causes stress on those areas of your repair which can cause cracks in your repaired section over time from this stress point being exposed constantly during normal use around that area of your project (i.e., walking across an unfinished floor).
  • Another reason why some people experience cracking with their repairs is that they used too much material in one application step without letting each application layer cure properly before proceeding to another step such as adding more layers or sanding down previous layers’ edges so they don’t show up later when painting over them again later down line after repairing has been completed successfully using proper products like those found within our store here at [this website].

How do you fix cracked wood filler?

  • Check your wood filler. If it’s not compatible with the type of wood you are repairing, or if it’s expired, this can cause cracks as the filler shrinks and expands at different temperatures. If your wood filler is more than two years old, buy fresh material so that this doesn’t happen again.
  • Use a filler that is compatible with the paint or stain you will use on your project after fixing all of those pesky cracks in your woodwork! Truthfully, using different types of fillers for each stage of a project isn’t necessary; just make sure that everything matches when all said and done!

Which is better wood putty or wood filler?

  • Wood putty is a fine powder that you can apply with an artist’s brush.
  • Wood filler is a paste that you can spread on with your fingers, or use a putty knife to spread onto the wood surface.
  • You can sand wood putty, but not wood filler. Use 120-grit sandpaper for this step if you need to remove all of the excess filler before applying another coat of paint or stain over it.
  • Wood fillers are available in different colors, so choose one that matches your existing finish as closely as possible (black will match almost anything).

How long does wood filler take to harden?

Wood filler dries in 24 hours, but the drying time will depend on the thickness of your application. The thicker your application, the longer it will take for the wood filler to dry; as a rule of thumb, thin wood fillers take about 24 hours to dry while thick ones can take anywhere from one week to two weeks.

If you’re using a thin application, you can expect it to thoroughly cure within just a few hours or overnight.

Is wood filler as strong as wood glue?

Wood filler is not as strong as wood glue. When you fill a small crack or hole, the wood filler will hold up just fine.

However, if you have a large crack, the wood filler might not be able to hold the piece together on its own.

In this case, it’s better to use a type of glue that’s stronger than wood filler and can fill larger gaps in your project. While these glues are stronger than the standard household variety, they will still only be able to fill large gaps when used in conjunction with other pieces of wood that need mending as well—they won’t act as standalone supports for an entire project like you might hope they would!

How thick can wood filler be applied?

When it comes to how thick you apply wood filler, there is no set rule. You can use as much or as little of the product as you like.

However, remember that the thicker your layer of wood filler is, the longer it will take to dry and cure. If you want to get your project done more quickly, apply thinner layers of wood filler (no more than 1/8” thick) instead of one big layer that’s an inch thick!

How do you use wood filler for large gaps?

If you’ve got a large gap between two pieces of wood, you’ll want to use a putty knife to apply the wood filler. First, apply the wood filler and then smooth it out with a wet finger. Let dry for 24 hours before sanding it smooth.

How do you fill holes in wood without wood filler?

To fill holes in wood without using wood filler, consider one of the following methods:

  • Use a wood patch. If your hole is relatively small (1/2 inch or less), you can use a piece of hardwood and some glue to patch it up. Cut the piece slightly larger than the size of your hole and clamp it in place while the glue dries. For bigger repairs, consider using two pieces of material in an L shape so that they fit over each other when pressed together.
  • Use a wood plug. This type of filler is best suited for larger holes or gaps; simply drill out a hole large enough for a plug to fit inside it, then hammer in this “plug.” The same approach applies if you want to match existing wood grain patterns when filling gaps or large holes—just select plugs with grains that match those already on your furniture or other items (this will make them less noticeable).


Hopefully, this article has answered your questions about wood filler. If not, feel free to leave a comment and let us know what else you’d like to know about this useful product.

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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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