Filling Voids, Cracks, and Defects in Wood with Epoxy – Ask Matt #19

I like to incorporate some goofy pieces of wood into my work.  Many of them have structural issues or voids that need to be addressed before they can be used in a project.  Epoxy works great for filling and stabilizing  knots, cracks, voids, and other defects in wood.

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West System Epoxy Resin (Gallon):
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Cabinetry and open seating

Welcome back to our home renovation and remodel.  Today, I am hoping to have the island cabinetry built out, as well as getting the leg

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Welcome back to the shop! I’m continuing on with the white oak island build. Last time I made the end panels for the cabinetry unit,

37 Responses

  1. Matt, will this stop rot? I have a piece that was rotting inside. Was thinking of filling it to stop the rot.

  2. I recently received some “FREE” rough cut walnut and cherry, 6-8″ wide by 8′ boards. They have a lot of checks/cracks, some go almost all the way thru their length. How far can l go using epoxy to fill/repair these problems, or I’m I better off ripping, jointing, and glue them together again

  3. Matt, I have a 60″ long live edge walnut slab. It’s a 7/4 thick piece and there is an 18″ long crack, 5/32″ wide starting at one cut end. The 2 adjacent surfaces are about 3/32″ out of plane at the cut edge across the crack, but otherwise the slab is very flat. I’m thinking of temporarily clamping a straight edge across to remove the slight twist and then filling the crack with epoxy. Do you the epoxy will resist the twist and hold? Or do I just fill as is and re-surface.?

  4. Hi Matt! Timy Mac, The Maker Apprentice hereI Never used epoxy so I need some guidance. I’m using 100+ year old oak barn wood for two end table tops. They have a few voids, pest damage, ect., but nothing that goes all the way through the stock. Should I rough cut to finished size and then epoxy the voids or go ahead and fill the voids and then rough cut. I’m having to decide where to cut the boards out of the stock so I don’t have to use so much epoxy. Make sense?
    Thank you,
    Timy Mac

  5. hi Matt!

    question: have you ever filled a crack with epoxy after you have installed a butterfly? if so, did you like the look, or did it detract from the logic of even having a butterfly?

    1. If I’m going to do that, I’ll fill with epoxy first and then install the butterfly. This keeps the epoxy from ghosting into the grain of the butterfly which keeps it looking crisp. The overall look depends on the application but I like having the cracks filled and stabilized with epoxy and adding butterflies just for show.

  6. Hi, I recently got a large piece of wood that I am going to use as a vanity top. I am wondering if you have ever used glass beads or objects in large voids before the epoxy as a decorative look and does anything different need to be done?

    1. I haven’t as it’s not a look that I particularly like but nothing needs to be done differently. The only thing to concern yourself with is keeping the objects submerged if they would have a tendency to float.

  7. Matt, great post. I tried this and it worked very well. I’m a total amateur too. One question: sanding dulled the epoxy quite a bit. Will my top coat (varathane take care of that or something else needed to make it shine a bit more?

    1. The top coat will bring back a lot of the sheen but if you’re using a clear fill that you want to not look cloudy, you’d need to polish the epoxy to a minimum of 1000 grit. Thanks!

  8. Planning a cherry wood project and will be using your methods to fill checks and cracks in the lumber. My plan was to finish the project with Waterlox original finish. How do you think this will work over the epoxy repairs?

  9. Hi Matt, love your videos! I am building a media center from hickory and want to use some “character” boards for door panels, one of which has a knot that is just perfect in size and placement, however, it has a void that is rather large. My question is: do I fill with west system expoxy before I run through thicknes planer of after? Thanks in advance, and looking forward to your future posts!

    1. Whenever possible, I fill before dimensioning. The epoxy will support the fibers as they are being planed so you wont get any tear or chip out and the epoxy will be all cleaned up once surfaced. thanks!

  10. I need some advice Matt.
    I built a coffee table out of some old fir beams that I milled down in the spring. The moisture content was good so I glued it and pocket screwed all the seams together. Sanded down to 180 and did a few layers of epoxy to fill the cracks. After being inside for a month it’s developing small cracks throughout the piece. What should I do?

  11. Hey Matt,
    Nice name by the way haha. I’m having my first experience with using Epoxy resin. I’m using west system 105 resin with 206 hardener with a jet black dye. I’m using it to fill in a few red gum slabs for some tables. I need some help. How bad is it if the resin I’ve poured in is overfilled? I’ve filled my cracks and defects but some I have overfilled by a little bit. Is this a problem? Can it scraped off after it’s cured and sanded. Just looking for some advice and tips to help me out. If you could be any help it would be awesome.

  12. Hey Matt!

    First time using epoxy to fill voids. I filled all of my voids in the White Oak boards I am using for a table top. The next day, a few of the voids soaked in more epoxy while drying and are now below the surface of the wood.

    Is it okay to add more epoxy to the already cured epoxy?


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