Wood filler is used to fill scratches, holes, and other imperfections in unfinished furniture and other projects. Although wood filler does not take stain well, woodworkers like it because it hardens as it cures and can be sanded down afterward. So why does wood filler not take stain well, and what can you do about it?
Wood filler rarely matches wood’s color or grain, so after staining, its color still differs. Its edges also collect staining, creating a darker outline. These issues are more pronounced with light stains than dark, and wood filler takes paint much better than it takes any sort of stain.
In this article, I’ll explain why wood filler does not take stain well, why filler should match your wood, and why you might use wood conditioner. I’ll talk about why sanding doesn’t help, why paint is a better solution, and explore whether wood filler is worth the trouble. Let’s get started.
Why Wood Filler Does Not Take Stain Well
Wood filler is useful. With it, you can fill holes, gouges, and other imperfections or mistakes on your furniture, making your project’s surface smooth and uniform.
However, wood filler doesn’t take stain well, which is mainly due to the reasons explained below.
It’s Not Entirely Wood
Wood filler, as you can probably guess, is not entirely wood. It’s made from a combination of epoxy or lacquer, sometimes with sawdust mixed in.
And because wood filler is a different material than your project, it’ll react to any stain you apply differently than the surrounding material.
Stained wood filler may be lighter or darker than stained wood. It might be a different hue, or it might be more or less saturated. This all results in a mismatch with the rest of your project, but it’s far from being the only element at play.
It Rarely Matches Your Wood’s Grain
Wood filler, being epoxy or lacquer, is smooth and doesn’t have grain. So, if your project’s wood has a clear or pronounced grain, any filler you apply has a chance of looking out of place because it doesn’t have the same pattern.
In addition, stain is so effective because of the tiny holes and grooves that textures wood. The stain collects in these imperfections, coloring the wood. The filler can’t emulate this, so it may react differently to the stain. And, this isn’t the only reason texture is important.
It Collects Stain, Which Highlights Imperfections
Even if you sand where you’ve applied wood filler, there will still be microscopic differences between the edges of the filler and your project. Though its margins may look seamless, you’d probably spot some imperfections if you were to inspect it under a microscope.
When you use stain, it’s possible that the filler will collect these imperfections, resulting in a darker outline around the area of application. This makes any imperfections or patch jobs on your project obvious. However, there’s still one last problem you need to look out for.
Not All Stains or Wood Fillers Are Created Equal
It’s well-known that when you use a different product, you may encounter differing results. Just as with anything else, how manufacturers make stains and wood fillers and what additives they mix in may differ between different brands.
While you may get lackluster results with one brand depending on what you’ve chosen, another may work better.
So, depending on which wood filler and stain you use, you might suffer all the above problems in a fiercer intensity than if you used another combination.
Why Should You Buy Wood Filler That Matches Your Wood?
Many wood fillers are clear, and for some projects, this works well. However, if you plan to stain your project, consider buying a tinted wood filler instead.
Tinted wood fillers have dyes mixed in and come in a variety of colors that may match your project’s wood. When you choose a color that resembles that of your project, the mismatch between your stained filler and your wood will be less pronounced.
In general, it’s a good idea to buy a wood filler that matches, and it’s even more so if you’re staining your project.
Why Should You Use Dark Stains When Using Wood Filler?
It’s common advice to use a darker stain when you’ve used wood filler on your project. Many woodworkers say that the mismatch between the filler and your project will be less pronounced. But is this true? Should you use dark stains when using wood filler?
If you’re staining a project with wood filler and want to minimize color and texture mismatches, using a dark stain is better.
Lighter stains are more translucent, and when they gather in imperfections, it creates an extreme color difference. Dark stains are less translucent, and stain deeper, unifying the colors and covering up any imperfections.
While you’ll still have a slight mismatch with a darker stain, it’ll be less extreme.
Should You Use Wood Conditioner Before Staining?
Wood conditioner is a finishing product that reduces the amount of stain that permeates wood. If you’re staining, it’s useful for many reasons.
If you can predict where color mismatches may happen, you may be able to apply wood conditioner before staining to keep the stain from accumulating too thickly.
However, this approach is hit or miss.
It’s difficult to make out tiny imperfections, and even if you apply wood conditioner, you may still have color or texture mismatches due to applying too much or too little.
Why Sanding Your Wood Filler After Staining Doesn’t Help
You may wonder if you can minimize the mismatches between your wood filler and your project by sanding it after you’ve stained. However, this is not a good idea.
Sanding to remove staining imperfections doesn’t work because it removes the staining from the wood filler, leaving only the clear or tinted epoxy or lacquer behind.
Staining works by applying color to the surface you place it on. It doesn’t permeate the material all the way through, and when you sand, you remove this surface layer, and therefore, your staining. In short, it’ll exacerbate any differences in color or texture.
If the problem is that your wood filler’s edges are bumpy or your project’s surface is uneven after applying it, it’s always better to sand before you stain your work. This is also true if you’re lacquering or painting it.
Why Paint Is a Better Solution to Staining Wood Filler
A commonly recommended solution to wood filler and staining related woes is to paint instead. But why does paint work better? And what are the potential upsides to painting instead?
Paint Coats Wood Filler Instead of Attempting To Change Its Color
Above, I said staining applies color to the surface you place it on. The biggest difference between staining and painting is that paint coats the surface of your project instead of trying to change its color.
Because paint coats instead of dyes, color mismatches between your project and your filler stop being a problem. With several coats, you’ll cover them both evenly, and if you sanded well enough to smooth down your filler’s margins, you might not even be able to make them out underneath the paint.
Paint Resists Spills and Weather Without Curing, and With Less Work
There’s a reason you must apply finishes after staining. Your project needs a clear coating to protect it from spills, weather, and other types of damage, and unfortunately, staining doesn’t do that.
These treatments may require curing for long periods of time or, sometimes, under special types of light. Setting this up and waiting for the process to complete can be tedious, especially if you’re under time constraints. However, some paint comes with these clear coats mixed in, and they require little time or special circumstances to dry.
All in all, it’s less work to paint your project instead. It’ll take less time, less effort, and require fewer supplies. And if you choose the right paint, it might not look all that different from a stained product..
Should You Use Wood Filler at All?
After reading all the above, using wood filler may sound unappealing. You have to worry about colors, textures, and the order in which you need to apply several things. Even if you do everything right, the margins of your filler still might be visible.
So, you may wonder if wood filler is necessary, or whether you should use it at all. For example, should you use wood filler on hardwood floors? [Can You Use Wood Filler on Hardwood Floors?]
Fortunately, you don’t have to use wood filler if you don’t want to. Many people prefer an au naturel look to their furniture, imperfections and all, and sometimes, lacquer or paint may cover up imperfections you thought needed it.
Using wood filler adds a lot of work to steps that come after it’s applied and comes with many extra complications. So, if you don’t have to use wood filler, it’s a safe idea to leave it out.
If you decide to use wood filler after all, it’s important to make sure that you’re actually using wood filler, not wood putty. This article by Family Handyman details why they’re labeled interchangeably in stores and how to tell the difference between them.
Wood filler doesn’t take stain well because it doesn’t share wood’s color, pattern or texture and collects stain in imperfections. Wood conditioners can lessen color mismatches, but sanding creates them.
As such, you should buy filler that matches your project, settle for darker stains, opt to paint or even refrain from using filler in the first place.