how to keep wood filler from cracking?

We’ve all had that moment when we need to fill a crack in wood and the wood filler starts to crack instead. It’s frustrating, but there are steps you can take to prevent it or fix it if it happens.

Here’s everything you need to know about keeping your wood filler from cracking:

Why is my wood filler cracking?

Wood filler is a material that’s used to fill cracks and holes in wood. It’s made from sawdust, glue, and wax; the combination of these materials creates a paste that can be applied to the surface of the wood.

The filler dries out as it ages and shrinks back into itself, leaving behind a small amount of space between itself and the surrounding wood.

When you sand away this extra space—or if it shrinks too much due to temperature changes—the wood will crack again where the filler was originally placed.

How do you fix cracked wood filler?

  • Use a putty knife to remove the cracked filler.
  • Clean the area with a damp rag and let it dry completely before applying new filler.
  • Mix fresh wood filler with water and apply it over the crack.
  • Let it dry for at least 24 hours, then sand down any areas that are too rough or have excess material on them (to prevent further cracking).

How do you preserve wood filler?

You can preserve wood filler by sealing it. This will prevent cracking and allow you to use the filler for a longer period of time.

The best sealer for wood fillers is polyurethane or varnish, but you can also use paint or stain. In order to seal it properly, however, you must sand your wood filler first. Sanding removes any rough edges that would make the sealers difficult to apply evenly on your project’s surface.

Can you seal wood filler?

You can seal wood filler to prevent it from cracking and help it adhere to the wood.

  • You can use a stain or paint over the wood filler to seal it, if you’re working on an exposed surface.
  • A spray-on sealant will protect both sides of the nail holes and prevent moisture from getting in them, making them less likely to crack in the future.
  • After applying a coat of stain or paint and letting it dry for about two hours, apply another coat before adding more filler.
  • If you have access only to paints that are not water-based (for example oil-based paints), then you should use one coat of primer first before applying another coat of finish as described above

Do you need wood hardener with wood filler?

The answer is yes, you can use wood hardener with wood filler. Wood hardener is a special type of glue that helps to make your wood filler stronger and prevent cracking.

This makes it easier to sand and finish your project. It’s most often sold in a separate container from the filler itself, but there are some brands that sell them together in one package (like this one).

If you’re having trouble finding it at your local hardware store or craft store, try looking online!

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

What’s the difference between wood putty and wood filler? Put simply, they are different types of materials that do the same job.

While both of these products are used to fill in holes and dents in wooden surfaces, they differ slightly in their consistency and application.

Wood putty is a soft material that comes in two varieties: oil-based and water-based. Oil-based putties can be sanded before drying, so they are often used to fill small holes and dents on furniture before painting or staining your piece.

Water-based putties dry more quickly than oil-based ones do but cannot be sanded afterward — if you need to get rid of excess filler after it has dried (as opposed to just leveling out your surface), you’ll have no choice but to scratch or scrape away at it with a razor blade until all traces of filler have been removed from sight (and smell!).

Will linseed oil stop wood from cracking?

You may have read that linseed oil can be used as a drying agent to stop wood from cracking. This is not true.

Linseed oil does not prevent wood from cracking; it prevents the wood from drying out, which in turn helps prevent cracking.

Because of this, some people use it as the sole drying agent when filling gaps in their wooden furniture or other projects.

While they’re right that linseed oil helps prevent cracks, many other drying agents are better at stopping cracks than linseed oil alone—and these other compounds will work even better if you combine them with the correct ratio of linseed oil for optimal results.

How long should wood filler dry before sanding?

You can speed up the drying process by using a blow dryer on low heat. This will help the wood filler to set faster, but not too fast, so it doesn’t crack while still soft.

The time it takes for wood filler to fully dry depends on the type of wood filler you’re using and how many coats you applied.

Some fillers take only 24 hours or so before they’re completely cured, whereas others take several days—or even weeks—to fully harden.


In summary, wood filler is a great product to use in your home and on your projects. However, it can be hard to know exactly how long you need to let the wood filler dry before applying another layer of paint or finish.

The good news is that there are many ways for preventing cracking when using this product. By following all of these steps carefully, it should be easy for you to get professional results every time!

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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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