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

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.

Products Used [Affiliate Links]:

West System Epoxy Resin (Gallon):
West System Epoxy Slow Hardener (Quart):
Metering Pumps:
High Density Filler:
Transtint Medium Brown:
Transtint Bright Red:

  • John Leonick
    Posted at 13:19h, 21 May Reply

    Do you have to completely clean out the knot before filling it?

    • Matt Cremona
      Posted at 04:42h, 25 May Reply

      No, the epoxy is thin enough to penetrate and encapsulate any dirt or debris.

  • Albert
    Posted at 13:19h, 30 July Reply

    Matt are you Maltese??

  • Albert
    Posted at 05:28h, 31 July Reply

    I am from St Julian’s Malta

  • Greg Wallwey
    Posted at 04:06h, 27 February Reply

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

    • Matt Cremona
      Posted at 05:33h, 28 February Reply

      It should if you can get the rotted area fully saturated

  • Ronald R. Hoppe
    Posted at 23:05h, 13 September Reply

    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

    • Matt Cremona
      Posted at 18:01h, 18 September Reply

      You can go pretty far with it and fill all the defects to end up with structurally sound material. I look at it as more of an aesthetic decision.

  • Brian Moran
    Posted at 12:26h, 22 October Reply

    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.?

    • Matt Cremona
      Posted at 17:24h, 23 October Reply

      The epoxy will hold but you might have a bit of spring back. I’d try the holding it flat thing and just resurface after the epoxy sets if necessary.

  • Brian Moran
    Posted at 17:46h, 23 October Reply

    Awesome. Thanks Matt.

  • Christopher Trucksess
    Posted at 20:58h, 15 November Reply

    What trans tint color do you use for black walnut?

    Posted at 21:09h, 12 February Reply

    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

    • Matt Cremona
      Posted at 17:27h, 13 February Reply

      It’s much easier to fill first and accept some epoxy waste but if you are concerned about it, cut everything to final size and then do your filling.

  • rick verwilst
    Posted at 20:59h, 02 March Reply

    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?

    • Matt Cremona
      Posted at 22:19h, 03 March Reply

      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.

  • Bill Harris
    Posted at 14:42h, 31 May Reply

    can a cured epoxy void on an edge be routered and cut on table saw?

  • Wendy Lakey
    Posted at 05:33h, 23 August Reply

    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?

    • Matt Cremona
      Posted at 17:48h, 26 August Reply

      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.

  • R
    Posted at 16:56h, 23 December Reply

    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?

    • Matt Cremona
      Posted at 21:21h, 24 December Reply

      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!

  • Bill Neef
    Posted at 20:45h, 04 February Reply

    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?

    • Matt Cremona
      Posted at 23:21h, 09 February Reply

      Waterlox shouldn’t have an issue adhering to the epoxy.

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