Can I polyurethane over wood filler?

Wood filler is often used to patch up small holes or cracks in wood, but what happens when you have to repaint your furniture and want a smooth finish?

Can you use polyurethane over wood filler? The answer is yes. And no. Here’s how:

Can you put polyurethane on wood filler?

There are some people who think that polyurethane can be used as a filler or sealer. But this is false. Polyurethane is a finish, which means that it goes on top of the wood after all other finish coats are applied.

It does not fill gaps or holes in the wood grain like a filler would do; it’s too runny for that!

Polyurethane is also not clear like you’d expect from an acrylic paint or stain (although they’re all made up of similar ingredients).

While you can get polyurethanes in different colors and sheens like flat, satin, and gloss finishes–they won’t be transparent enough to actually replace these types of paints if your goal is just to cover up imperfections in your project’s surface.

How do you cover fillers in wood?

Wood fillers are used to fill in holes, cracks, and other defects in wood. They can be created from different materials depending on the desired result.

For example, you can use a filler that matches the color of your wood or one that is darker than your wood so it will blend in with its surroundings better.

Wood fillers are available in both liquid and powder forms, with each having its own advantages and disadvantages.

Liquid fillers have less shrinkage than powders but take longer to dry; powders dry faster but have more shrinkage when drying.

In addition, some liquid-based fillers include an adhesion promoter that improves the bonding between a layer of polyurethane coating (PU) and the surface below it by making them “bond together” better than they would otherwise do so by themselves alone.

Can you seal wood filler?

If you want to seal wood filler, make sure that the filler you choose is compatible with the finish you are using. Some fillers may not be suitable for certain finishes, such as a lacquer or oil-based varnishes.

If in doubt, ask a store associate or read the product label on your can of wood filler for more information about compatibility.

Can you put varnish on wood filler?

Yes, you can use varnish on wood filler. Of course, if you want to do it, you can. The filler will be visible and may not be as smooth as it would be if you used polyurethane.

But if that doesn’t bother you and the result is what you want then go right ahead!

It will work fine for a few hours but when left for more than a couple of days the varnish will begin to crackle and peel away from the surface of the wood.

Will polyurethane fill in scratches?

Polyurethane isn’t a filler. It’s a type of sealant, and it won’t fill in scratches.

However, you can use polyurethane to seal over scratches if you want to. If you’ve got a new piece of furniture that has some noticeable scratches in it, and they’re not too deep, this will work well for filling them up with the clear coat on top of the wood filler that was used before staining/sealing it with polyurethane (which is what we recommend). The result should look just as good as an all-polyurethane finish.

Should you use wood filler before or after staining?

There are a few factors you should consider before deciding whether to apply your wood filler before or after staining.

The first is the type of wood filler you use. If it’s water-based, it’s best to apply the filler before applying a stain or paint.

This will help prevent issues with the stain not adhering properly to the wood and will give you an even application on both sides of the surface.

If you’re using a solvent-based wood filler, however, it’s best to wait until after staining to add more layers because this type of product contains chemicals that can affect how well your finish holds onto the surface (and may also cause discoloration).

How do you make wood filler not noticeable?

If you’re trying to make wood filler less noticeable, the best thing to do is use a filler that’s the same color as your wood. Another option is using one that’s slightly darker or lighter than your wood—this will help it blend in even more.

If you don’t want your finished project to have any grain at all, then fillers are probably not for you. The filling

also takes some trial and error because different woods require different types of fillers depending on their density and how porous they are (some woods absorb more than others).

In short: if there’s just a small gap between two boards, try filling it with glue first before adding any type of filler so that everything sticks together better!

How do you make wood filler look natural?

To make wood filler blend in with your wood, be sure to use one that matches your wood. If you’re covering up a large area of damage, it may be best to purchase an extremely dark-colored filler that’s a shade or two darker than the wood.

Darker fillers can help hide small imperfections in your woodwork and make it look more natural. When applying the filler, use a brush rather than spreading it on with your hands; this will ensure even application and reduce lumps on the surface when dry.

Let the filler dry completely before sanding and finishing off with polyurethane if necessary (see below).


The bottom line is that you can always use a little bit of wood filler to cover up cracks and other imperfections in your wood, but if the filler is too noticeable or stands out too much, then it’s not worth using.

If you want to cover up something completely, just use a little bit of paint on top of it first (make sure not to put too much though).

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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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