Is Wood Filler Actually Stainable: An Experiment

In one of the woodworking Facebook groups I follow, wood filler disasters are one of the most common “help!” questions I see. They really all come down to the same question, though; is wood filler actually stainable?

Most wood fillers are formulated to take stain. However, stained wood filler frequently looks significantly different than the surrounding wood, creating an undesirable appearance. This problem is more prevalent when working with lighter stains than darker stains.

To demonstrate this, I grabbed four different wood fillers to test out; three from popular brands, and one DIY version. Keep reading for the results!

Note: This blog contains affiliate links. If you click and make a purchase, I may receive compensation (at no additional cost to you.)

Is Wood Filler Stainable? Four Types Compared

I started with four types of wood filler: Minwax’s Stainable Wood Filler, DAP’s Plastic Wood, Elmer’s ProBond Wood Filler, and a DIY wood filler made from wood glue and sawdust.

Each wood filler was tested using two stains; a dark chestnut from Sherwin Williams, and “Gunstock” from Minwax.

Stainable Wood Filler Experiment: The Process

Since there were four wood fillers and two stains, I cut eight pieces of scrap wood and drilled four holes into each piece (the drill press was handy here.) The holes were somewhat random; if a wood filler was really fantastic, I wanted to be forced to search for a hole.

Then I filled wood filler into each hole, and let it dry for about three hours. My holes were pretty shallows, so I expected that would be enough time.

Here’s how each wood filler looked at this stage:

After the wood filler was dry, I sanded the blocks smooth, then applied the stain, wiping it on with an old rag.

The technique does matter – by wiping on the stain (and not painting it on and wiping it later,) I restricted the amount of stain that the wood could absorb. This helps both the wood and the wood filler absorb stain evenly.

The blocks then looked like this:

Stainable Wood Filler Experiment: The Results

The clearest takeaway from this experiment is that the darker stain is significantly better at disguising the wood filler than the lighter stain. In every single case, the wood filler is less noticeable on the board with the darker stain.

In terms of which wood filler stained the best, Minwax’s Stainable Wood Filler was the closest match to the surrounding wood. It was not flawless, however, and still stood out when used with a lighter stain.

The DIY Wood Filler and DAP Plastic Wood also performed well. The DIY Wood Filler was almost invisible on the darker wood, and there was one hole that I couldn’t find at all!

Elmer’s ProBond Wood Filler, however, stained significantly worse than the other three. It stood out on both the lighter and darker stained boards, and on the lighter board, didn’t even turn a shade that was elsewhere on the wood.

All that said, though, none of the wood fillers did a particularly good job on the lighter stain. They all stood out significantly from the surrounding wood. So what do you do when you need to use wood filler with a light stain? Read on!

Wood Filler and Light Woods/Stains

As we learned above, dark stain does a decent job of disguising wood filler. But light stain, or no stain at all, does not. The easiest way to deal with this problem is to avoid it entirely. Either don’t use wood filler, use it sparingly (small nail holes only!) or paint your piece instead of staining it.

You might be thinking “no wood filler??” But the rustic look is in, and in most cases, looks better than a piece with lots of obvious dots all over it where you filled in flaws with wood filler.

And if you absolutely must use wood filler, consider painting your piece. Wood filler looks excellent with paint, since the main problem with it is that it doesn’t match the grain of the wood. By painting over the wood filler, it won’t be noticeable at all.

Finally, if you’re really determined to use wood filler with a light stain/wood, grab some pieces before you start and test the wood filler and stain with some different application techniques on those first (see next section.)

You probably won’t be able to make the wood filler invisible, but some testing will improve your final product.

Staining Wood Filler: Tips and Tricks

• DIY Wood Filler – DIY wood filler is made by mixing some sawdust from your project with a little bit of wood glue. Emphasis on the “little bit.” Glue darkens the wood filler, so use as little as you can get away with.
  
  I typically put in a drop of wood glue at time, and mix in between drops. When the wood filler seems sticky enough to stay in the hole, I stop adding glue and pack it in as tightly as I can.
  
  As shown above, this won’t solve all your staining woes, but it will come in handy if your run out of wood filler! And it works particularly well if you’re not planning to stain your piece, since if you make the wood filler out of sawdust from your project, it will match the surrounding wood perfectly.
  
• Test the Stain and Wood Filler in Advance – You don’t know how a wood filler and stain are going to look together, and you never want to experiment on your almost-finished project. Instead, grab some scrap wood from the piece and test things out there first! If you don’t have any scrap piece, test on the bottom, back, or another location that won’t be seen.
  
• Purchase Colored Wood Filler – If you’re not planning to stain your board, you can purchase wood filler that matches the color of your wood. This might take away some of the unknown.
  
• Color the Wood Filler Before Application – One option is to stain your piece and the wood filler separately. That way, you can be confident your wood filler matches the surrounding wood before applying.
  
  Start by staining your main piece. Then simply mix a little stain into your wood filler before applying, matching it to the surrounding wood as best you can. Definitely test your stained wood filler on scrap wood or an inconspicuous portion of your project before applying it to the main piece.
  
• Use Wood Conditioner – Wood conditioner reduces stain absorption into wood. Most of the wood fillers absorb more stain than the surrounding wood (and therefore appear darker,) and wood conditioner could help with this. Once again, test this out on scrap wood first, but it’s an option that could help!
  
• Type of Stain Matters – I used typical oil-based wood stain in these tests, but it’s worth noting that there are other stains on the market that might absorb differently with wood filler. Always test your wood filler and stain combo before applying it to your project (am I starting to sound like a broken record?)

Final Thoughts

Wood filler is difficult to stain in general, so it’s always best to test out your process on some scrap wood before you start to ensure the wood filler will look exactly how you want!

There’s really no silver bullet to staining wood filler; testing different techniques is the only way to figure out what will look best on your particular project.

Finally, if you found this post helpful, go ahead and save it to Pinterest so you can find it again later!