Filling Knotholes with Epoxy?

Filling Knotholes with Epoxy?

I have a piece of black walnut that I intend to use as the top of a small table project. It has beautiful graining and is a single, wide board (just over 15″ wide). Unfortunately, it has two knotholes (about dime-size each) with one going through the board to the other side. Can I fill the voids with epoxy or is there a more elegant, but easy, solution? Also, can the board be sanded by a commercial drum sander once the epoxy has hardened? – David Long

Chris Marshall: If I were in the same boat, David, the first question I’d ask myself is what I want the end result to look like. If you want to make the knotholes completely disappear, that will be very difficult to do with any sort of fabricated wood plug. I’d probably rip the board at the band saw to remove strips of wood where those knotholes are, and re-glue it. That’s about the only way to make them vanish, but you’ll alter the grain pattern of that nice, wide board in the process. Next option: leave the knotholes. Yes, you can fill them with a good quality epoxy and then scrape or sand the areas smooth when it cures hard. It’s an excellent solution. Tint the liquid epoxy if you want to, with a colored dye powder. I’ve used black before, and I like the effect. It makes the knots less noticeable, and the black coloration looks entirely natural on dark wood. A third route would be to replace the knotholes with something like a contrasting butterfly inlay. Design-wise, it introduces a different shape and color that calls attention to itself, but it might be very interesting. Choices, choices! Always choices.

364QALIQUID-INLAY

Tim Inman: I think epoxy is perfect for this kind of repair! Tape off the “bottom” of the void so the epoxy will not run out. Then fill. Expect to fill more than one time. I would use a pretty fluid version of the resin, and expect that the first pour will soak in quite a bit. The second fill will probably do the trick. I mask off the surrounding area so I don’t have epoxy resin all over the place. Color the fill with your favorite source of color. One of mine is some sawdust/sanding dust from the exact board I’m filling. Collect it and mix it into the resin before you pour your fills. You can use color to accent these little knots, or to diminish them. Have fun – and practice on something else first!

Posted in: