How to Fill Voids and Knot Holes in Wood
Occasionally, you will get a piece of gorgeous wood that has voids or knots in it. You wouldn’t want to add wood putty, because it wouldn’t retain the look of the knots. But, you want a smooth surface. The solution is to fill the wood knots and voids with epoxy. The results will be beautiful and you’ll be hard pressed to find the patch afterwards.
Materials:
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Instructions:
Begin by taping off the area around the holes, voids or knots. Press the edges of the painter’s tape down to seal it against the wood.
Remove the epoxy from the packaging. (I used Gorilla Glue Epoxy glue that sets up in 5 minutes.)
Snip or snap off the tip of the epoxy tubes.
Press the cap out of the plungers before trying to depress the plunger. Retain the cap to use if you have any leftover epoxy.
Depress the plungers and squeeze the two part epoxy into the packaging mixing tray. Stir the epoxy with the enclosed wooden stick until the glue is thoroughly mixed (should appear cloudy and all one color.)
Pour or spoon the epoxy into the voids, holes or knots. Do not let the epoxy touch your skin. Be sure to fill to the top or slightly over the top of the holes. Use disposable wipes to clean up any misplaced drips.
Allow the epoxy to harden and dry. Depending on the weather, the epoxy will likely need to dry and harden overnight.
When the epoxy has fully cured, remove the painter’s tape.
Sand the epoxy until it is smooth and level with the rest of the wood surface. Avoid the temptation to keep the sander on the epoxy too long or the glue will gum up the sandpaper. It’s better to use several passes and allow the epoxy to cool off between sanding.
Finish your wood with stain and/or topcoat of your choice. You can see my tutorial for refinishing reclaimed lumber for more details. You can read more on repairing holes in wood in “This Whole Post is on Repairing Holes.”
When you’re done it should be hard to locate the epoxy filled area! Can you spot it below?
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Will this Gorilla glue epoxy yellow after time?
This was so helpful! I used some reclaimed wood as a table top and the knots all came out while sanding. This solution would be perfect!
Hi!
I have a new pressure treated pine deck that is ready to be stained after a year. Knot holes are needing to be filled ( large and some small). The builder used nails instead of screws to put down the boards, so turning them over would be a huge problem. Can I use the Gorilla epoxy to fill them? If so, will staining after be a problem. And will the epoxy come out in the future?
Misery, if the holes go all the way through the epoxy will drip through and not fill the hole. The epoxy can’t be stained after the fact. They show up as clear. The epoxy shouldn’t come out in the future. You can also try filling the holes with a wood hardening product. Scott has a great article on exterior wood hardeners here: https://thecraftsmanblog.com/the-wood-filler-epoxy-test-year-3/
we have mesquite mantel that already has tung oil applied. we’ve now decided to fill the knot holes with epoxy so what do we need to do to prep before pouring the epoxy?
Besides cleaning any dust, you probably don’t need to do any prep work but you might want to contact the epoxy manufacturer to double check.
I have a 8 foot long x 6 inch thick x 10 inch fir beam that has already been mounted on my fireplace. There is a section on the beam that has a knot that has dropped some wood out. I don’t want to lose anymore out of the knot. Will epoxy work if I wait a bit longer to place in the hole, so it doesn’t run out? So nervous…I don’t want to ruin it…I will be staining after wards. The area is on the face of the mantle..so worried it will run out….what to do?!?!
Yes, the epoxy will run out as it is liquid and fill always self level. You’ll have to either remove the mantle to lay it flat while adding the epoxy or use a different filler that isn’t liquid.
Would you suggest doing 2 pours with a deep knot?
You can, but you could do one pour, just need to allow more time for it to cure.
Thanks! I think I will do one and be patient.
Hello, I love your post and I’m wondering if this will work for my purpose. I have a reclaimed bridge timber I pulled out of the water. Since this is going to be a table, I really want to fill in the holes somehow. But more importantly, there is a rotten area that I don’t want to dig out. I’m wondering if the Apoxsee will hold that together so that I can stain and put clearcoat over the top of it? What do you think?
You need to dig out any rotting wood to get to solid wood. Otherwise, the epoxy won’t have anything solid to grip to.
Actually it’s hard to describe, but this is a long haul and there is solid wood around the perimeter and the center is rotten. I really don’t want the whole any deeper. So I was wondering since it does have good wood around it, would that work?
I’m sorry I can’t tell you without seeing and feeling it.
Hi, filled in knot holes on cedar top for end tables. I sanded off and used a polycritic clear gloss but the knots are still super shiny and looks awkward any suggestions.
Here’s a little tip to get a better color match. Sand the wood first, then take the sawdust from your sander and mix it with the epoxy.
Any ideas on how to fill in the areas between each of the boards on a custom table I built. I want to use a self leveling clear coat on the top but some of the boards have space between each other that would leak through. Thanks
I’d tape the underside of those cracks so they will get filled in with the clear coat but won’t continue to drip through.
I’d tape the underside of those gaps and let the self leveling clear coat fill in the cracks and cure.
Hi Brittany, what about the tanins that may “bleed” into my new stain? I would like to use something other than a shellac – possibly sealer, epoxy? etc. which would prevent this but still allow the stain to be beautiful. Any suggestions? Thank you so much!
Donna, I would think the epoxy would seal the knots so you wouldn’t have that issue, but I’d check with the manufacturer of the epoxy first to be sure.
Brittany, Your tip is exactly what I was looking for. I am making a bench for one of my grandkids with his name engraved in the top. But the boards have knots in them and I was searching for a way to handle the knots. Your tip to just fill the knots holes with Gorilla Glue Epoxy is a simple and easy solution. Thank you very much.
So happy to hear this Mike! Hope your grandkids enjoy the bench.
Can you add a color to the epoxy?
I have a solid oak worktop in my kitchen. Over a period of time, a leaking tap (mounted in worktop) has caused damage to the wood. So when I scraped it and sanded it back, there is now a hollow around the tap hold. Can I fill it in with epoxy and before I replace the leaking tap. I dont really want to have to change the whole worktop.
Cathy, I would try to dig out as much of the rotten area as you can first. Then you could use epoxy, if you think it would look okay (like a knot there.) Or you can use Bondo to repair is like I show in this post: https://prettyhandygirl.com/how-to-fix-small-areas-wood-rot/
Also, you might want to remove the faucet first and use tape to make a boundary for the epoxy. Otherwise, it might take hold on the faucet and make it difficult to remove.
Hi
My table i have just purchased has had pine inserts put in where the knots have happened and it looks a bit of a miss match. Im looking to digging out out these pine inserts and using epoxy to refill them. The table how ever has already been clear stained and wax. When i sand down the epoxy would i have to re stain and wax the whole of the table again or could i just stain that one area?