113 – Fixing a Knot

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Ever find yourself short on material and that one board you really need has a nice open knot in it? You could always go out and buy more material, but sometimes its just easier and faster to stabilize and repair the knot. And instead of trying to hide the knot, sometimes its just better to embrace it, and make it look look resinous and natural. And that’s the goal here. I use an epoxy/dye mixture to create a stable and decorative knot.

Categories: Techniques, Whisper Minis

Comments

  1. Marty March 14, 2010

    I am getting old but I swear to God I’ve seen this before. I think it has been posted on TWW previously, not that it’s any big deal or anything.

    •  
      thewoodwhisperer March 14, 2010

      I had the same reaction Marty. I couldn’t figure out why I thought this was posted already, yet I couldn’t find a trace of it on the site. Now here’s what I’m thinking: in the Guild I discussed this topic in a live session. I believe at around the same time, I recorded the footage for this video, and just never released it to the public. But the Guild video went out as normal. So as a Guild member, I think you are having the same reaction I did.

      • brian schmitt March 23, 2010

        when you showed how to make those pencil holders you used the same process to fix a crack is that what you are thinking of.

        •  
          thewoodwhisperer March 23, 2010

          No it was the Guild think I mentioned above.

        • brian schmitt March 23, 2010

          could you show how to make a dutchman patch. i would like to see some different ways to do it.

  2. I really like the west system for this application, in fact I’ve use it quite a bit on waney edged board to build it up to look uniform and solid, like this http://i960.photobucket.com/al.....Medium.jpg
    This was a piece of burr oak with all sorts of holes.

  3. Jeff Madre March 14, 2010

    Thanks Marc, I’ve been looking for this and couldn’t find it. Even so, I was playing it back in my head as I attempted an epoxy repair last week.

    If I remember correctly, you played this video during a live guild session. I remember the questions afterward about you using the Stanley plane instead of your Lie-Nielsen.

  4. Tim G March 14, 2010

    Marc, we all appreciate the videos. To answer your question, this was in the Arts & Crafts table pt 2. Either way, thanks for keeping up the great work!

    •  
      thewoodwhisperer March 14, 2010

      I may have filled a knot in that episode, but this footage definitely wasn’t from that one. The project I was working on at that time was the steamer trunk. Jeff actually refreshed my memory on this one. I used this footage to kick of a discussion in the Guild last year. But for some reason I decided not to release it on the main site…..or I simply forgot.

  5. You made a cardinal mistake.

    You should always show your audience the end result.
    I was disappointed that you didn’t show me what the board looked like after running through your planer or drum sander… and then what it looked like after applying a finish.

  6. Chip March 14, 2010

    I remember this video, but the way I remember it, you didn’t tape the bottom of the board and some epoxy leaked out the bottom. One thing I love about your site is that you show us that everyone makes mistakes, and you show us how to fix them. That’s real important to us beginners who might get discouraged when things don’t come out as we planned.

  7. Frank Kovach March 14, 2010

    “Fixing” a knot? And here all this time I’ve been thinking that the more knots a board has the better it is! At least that’s what the guy at my lumber dealer keeps telling me! $55 a board foot for knotty pine is a good deal right? :) And just for everybody’s peace of mind, I can say absolutely, unequivocally, with 100% honesty and integrity that this video has never been posted as a podcast. Case closed.

  8. Wow, dude! Look at the size of your new shop! Sa-weet! Bet you’re loving that after the stint in the 3-car… hey, how high are those ceilings anyway? Did the house really come with that 5-car?

    Sorry, couldn’t resist the déjà-vu :)¡

    •  
      thewoodwhisperer March 15, 2010

      haha funny guy!

  9. Dan March 15, 2010

    Great deal Frank, where do you get your lumber? I, too, would liked to have seen the epoxy knot after milling. When running the board through the jointer/planer do you worry about tearout around the knot or on the knot itself?

    •  
      thewoodwhisperer March 15, 2010

      Generally, you still want to treat the area gingerly, so light passes through the planer are the key. But for the most part, the knot is now completely stabilized by the epoxy fill. That’s why its important to use a looser epoxy mixture for this, since a good amount of it will not only fill the hole, but also absorb into the surrounding wood, thereby strengthening it.

    • Frank Kovach March 15, 2010

      Actually, I use my local Wood Hobby Shop at Marine Corps Base Camp Lejuene, North Carolina. It’s actually one of the last of its kind in the military, from what I understand. I have never bought lumber anywhere but there so far, I have only been doing this woodworking thing a little over a year now. They get good deals on a good variety of rough cut lumber, and the shop is fully equipped so it’s easy to buy cheap but good quality stuff and mill it there to get it ready to use. Sometimes you have to sacrifice because you’re not getting “top quality” because of knots but overall it’s worth it because the lumber is so cheap. I could have used this info, however, a few months back because I had a piece of 8/4 walnut that had a pretty significant knot actually caused by a nail stub that was in the tree when it was harvested that we found just before the board went in the planer (thank God for that!) but I had a big chunk of unusable walnut. I was experimenting with some different types of wood glue and discovered that THAT DOESN’T WORK. Using this epoxy method probably would have enabled me to make another entire cutting board for my family for Christmas, rather than keeping it as a souvenire. I guess it wasn’t actually a knot but a place where the wood had rotted around that nail and kind of crumbled, causing a large hole in that area. I just couldn’t figure out how to fill it to make it useable, and ended up cutting that chunk out. Oh well. Live and learn.

      • Dan March 17, 2010

        Semper Fi!!! I used the MWR hobby shops many times. What a great opportunity to work on your vehicles or do woodworking on base. I was stationed there from 1989-1995, 1999 with many deployments. Is the wood shop still near the car hobby shop? Does the MWR still have signup sheets for funding at the woodshop? If so then the word needs to be spread so that the opportunity to escape the stresses of the Marine Corps is not lost and Marines have the opportunity to create items for their homes or barracks. I used the hobby shop to make plaques for my Marines when they where discharged or reassigned to other units. Made me feel better than buying the entire plaque, still had to purchase the name plates though. Thank you for your service, good luck, Semper Fi.

        Dan

        • Frank Kovach March 17, 2010

          Semper Fi back at ya! If you left the Lejeune area in 99, then you almost wouldn’t recognize it now. A lot has changed, including the way we pronounce the name. (Ask me about that another time.) The woodshop shares a building with the auto body shop, and both are adjacent to the auto hobby shop. I don’t use that quite as much now, but then again I actually live a little closer to New River so I have been using theirs more. The wood shop requires you to watch a one hour video mainly focusing on safety, then you can either pay a $45 a year membership or pay $3 a day for the use of the shop. They have a pretty nice selection of wood that pretty much stays constant, all rough cut, with the lowest prices per board foot that I’ve seen. Sometimes they get some real beauties, like about a month ago they had a 12 or so foot long piece of 8/4 mahogany that was 21 inches wide! The planer is 22 inches. You couldn’t have put that thing on the jointer though, except to do the edges. When you walk in, you sign the ledger and go to work. They have some basic supplies which you can buy, but the real attraction is just a nice, big, ventilated space with a dust control system and plenty of workbenches, assembly tables, clamping racks, and tools. Two Sawstops, a cabinet and a contractor saw. A big chop saw, two compound miter saws, another chop saw that is in a permanent dado setup with height adjustment, a router table, a shaper, a molding shaper, planer, jointer, three band saws, two drill presses, horizontal drum sander, oscillating spindle sander, horizontal belt sander and vertical belt sander, two lathes, three big downdraft sanding stations. They sell plywood too, and have a panel saw to break it down. Sounds like I’m trying to sell it to somebody. I just wish they would stay open 24/7. It’s great.

        • Dan March 18, 2010

          sounds just like I remember it. As for the ‘selling it to someone’ part I hope you did. Well, time to get another corned beef in the oven and then back to my humble garage shop to continue working on the sofa table from the honey-do list. Keep your head down…Good luck.

  10. Jason Kreger March 15, 2010

    Marc,
    Would it also be wise to hit the entire area with a little CA glue prior to filling with epoxy? This way the CA could soak in and stabilize all of the fibers around the knot too.

    •  
      thewoodwhisperer March 15, 2010

      You could, but unless you have an issue with the grain being soft, I wouldn’t worry too much about it. This less viscous epoxy does a great job of soaking into the fibers. And if I had to choose between CA and epoxy being embedded in the wood, I would choose epoxy. It feel stronger and more durable. CA is rather brittle.

  11. Trevor March 15, 2010

    Where did you get your epoxy cans with pumps?

  12. Todd March 15, 2010

    Marc,

    Can’t believe I saw you using an old Stanley block plane. Great Mini!

  13. Andrew March 15, 2010

    When you tint the epoxy, does the void end up darker than the surrounding knot?

    •  
      thewoodwhisperer March 15, 2010

      Depends on the knot and the dye. The goal is to try to match it up as much as possible. But I find that a mission brown dye usually gets close enough.

  14. JP Knapp March 15, 2010

    Why did you need to block plane it smooth before sending through the planer? Could you have just sent it through directly?

    •  
      thewoodwhisperer March 15, 2010

      Well you could, but I don’t like to. That big blob of epoxy on top of the wood can be a little rough on the blades. Plus, since the rest of the board is below the blob, its a little tricky to estimate the first pass or two in the planer. And if you catch too much of the epoxy, you could potentially pull the whole thing out. So I may be babying my planer a little but I prefer to play it safe and block plane it down first.

  15. Vic March 15, 2010

    About a month ago, Dan (Dan’s Basement Workshop in the Chatroom) was filling a void in a knot with some epoxy. I suggested he try to use an random orbital sander without the sanding disk on the board to vibrate any bubbles to the top. I think I saw that somewhere as a trick of the trade, but don’t remember for sure, might of been Woodworks. Anyway, worked like a charm. It’s the same principle used when working concrete.

  16. ediazf March 15, 2010

    Maybe a little rubber mallet hits arround the knot with the epoxy on it would help for better penetrationm especially with thicker epoxy mixtures..

    love the site, cheers from Chile!!

  17. It works!!! I recently used the trick on some oak. I also thought I had seen you do it on a previous video. I do like the idea of buying the epoxy in bulk. I haven’t noticed it being sold in the big box stores. I use the small tubes, but they are more viscous. BTW, I don’t begrudge you having a large and well equipped shop. You’re the one who had the talent and initiative to get there. My shop is small, but I don’t have to rely on it to make a living. It’s just a hobby. Keep up the good work!!!

  18. John Poulos March 16, 2010

    Marc, the mini was great! Thanks for the good info. Two questions:

    1. You mentioned that too much epoxy could be tough on the blades. In general should you use an older “utility” plane for planing down the epoxy? How tough on the blades is this stuff?

    2. How long are those cans of epoxy good for (shelf life)? At $155 for the set, they kinda put it out of reach for the hobbiest unless they last forever, lol :) Thanks for the awesome site and the entertainment!

    - John

    •  
      thewoodwhisperer March 16, 2010

      Hey John. I don’t really know how bad it is. But I use my old Stanley for that work. Part of the reason is the the epoxy seems to also build up on the bottom of the plane and is tricky to remove. So I do consider the Stanley my “utility” plane and I reserve it for these “dirty tasks”.

      As for the shelf life, I am not sure there is one. As long as the parts are kept separate, it seems it should last for quite some time. I have had my cans for about two years now. The only change is that the activator has gotten darker. But the stuff still hardens up as much as it did on day 1. So, I still think its a good investment, even for a hobbyist.

    • You don’t need the $155 kit unless you plan on doing fiberglassing; that’s something boat peeps do… and hockey players like myself that get skate cuts in their composite sticks :-(

      All you need is a quart of 105B resin ($30), 205B fast hardener ($18), the pumps are super nice for $13 and you’re set. ~$60.

      I also bought the 404 high-density filler for $14; I use the filler to fill large gaps mostly for non-furniture, but still useful. You hardly use any to build a gap-filling epoxy.

      BTW, I sharpied the plungers for the pumps to mark the 50% line. If I just need a little bit, plunge until the mark just goes into the pump.

      I have a flush plane I use to level the epoxy after a fill (within the first hour of pouring it). To remove the uncured epoxy, I put the iron in acetone for a minute then wipe it off. Granted, this flush plane is all that I use for leveling the epoxy… not my nicer planes.

      •  
        thewoodwhisperer March 16, 2010

        Good point Paul. I always link to the kit, but I didn’t realize it came with the fiberglass crap.

  19. Kfir April 10, 2010

    Hi,
    Hehe, why double posting is a problem. I’m not a woodworker, but enjoy watching the videos here at the site.
    Guys, it is not a patent to put some epoxy on wood.

    Second thing, can you post a photo of the wood after milling. I want to see how it will look like as a finished product.

    Keep up the good work, hehe, well, this is more then good!

    Thanks,
    Kfir

  20. I did a demo of this last year at the WIA show using Gorilla Epoxy and sawdust. Did it this year too at the Gorilla Booth. Video is posted on Gorilla Glue’s facebook video page as well. Nothing original for sure, but a hell of a way to fix minor imperfections, especially on the inside of a case. BTW, thanks for stopping by, Marc.

  21. William Burlingame October 12, 2010

    Andy – Thanks for the video. I’ve mixed sawdust into wood glue, but hadn’t considered it for epoxy. I have used epoxy to fill know holes, but always bought a nearly black variety. I have some rough sawn lumber that will benefit from this tip.

  22. Patrick Ferguson January 14, 2011

    Andy….I am getting ready to finnish a dresser I built of cherry wood. Every thing has been sanded to 220 grit and will be left with a clear Laqure finnish. The top has some charicter with some dark (reddish brown) knots and cracks from surface to 3/8″ deep. I whould like to fill these with an ultra clear material so they will be seen all the way thru. Bottoms are naturally sealed. What product should I use? Thanks in advance for your help.

  23. Alex Harris April 10, 2011

    Really good video Mark!

    Just an idea but by using a vrbrating sander with a very fine grit you can virbrate the surface of the wood causing the air pockets in the epoxy to rise out of the glue. I wouldn’t say it is vital but they certainly do a similar thing with concrete.

    (TeenWoodworker)

  24. Alice April 5, 2012

    Hi! I so wish I had found your site and watched this video about 2 months ago! However…..I hope I’m not too late for a couple of questions. I am working on a large project with wormy maple. I am using clear epoxy (Systems Three Clear Coat) and it is not filling the holes. My guess is that they are sealed, just not filled, and I would rather they not accumulate dust and whatever over the life of the piece….. I’m planning on using the blue tape to act as a dam around the edges of the piece and then pour the epoxy in the holes. Does the epoxy stick to the tape at all? Is that a good idea? Is there something that would be better to use? The all edges will be visible…. Now that I’ve seen this video, I realize it would have been best to fill the holes before construction, but alas!, it’s too late for that now. Also, can you scrape cured epoxy with a cabinet scraper to remove drips and runs and then hit it with a coat for final finish? Thanks so much! This is a great site, I also used your technique for free hand inlay and it turned out really well for a first attempt! If it works when it’s all said and done, maybe I’ll be brave and post a pic!

    •  

      Hi Alice. I don’t really do epoxy finishes so my knowledge of them is fairly limited. But in general, epoxy does stick to epoxy. So you should be able to fill the holes as needed. And yes, the epoxy will bind to the tape. So keep that in mind with your strategy. As for drips, you can certainly scrape them away. Once you have the area leveled, you will be left with an obvious rough spot. So it probably is a good idea to rough up the whole surface equally before re-coating. So many a nice light sanding over the entire surface with 320 grit. That will also give the surface a bit of a mechanical “tooth” for the binding of the final topcoat. From what I know of epoxy, you should be OK doing this process.

      • Alice April 6, 2012

        Thanks Marc! That’s very helpful.

      • Lisa August 26, 2012

        Hi! This is exactly what I need to do with a big ugly hole of a knot I found on my brand new deck. I don’t mind the look of the knot, just the fact that my 3-year old could stub her toe or hurt her foot running barefoot over the sharp edged hole. We haven’t cleaned/sanded/stained the deck yet as we are waiting for the pressure treated wood to dry. Could you please recommend a type of epoxy I could use that I could find at Lowes? You mixed two liquids together in your video before you added the stain…and I’m so clueless as to what those liquids are as I have never worked with epoxy.

        •  

          Hi Lisa. All epoxy comes in two parts: an activator and a resin. When mixed together in the proper ratio, a reaction causes the material to harden. So no matter what brand you get, you can expect this to be the case. But you can buy different varieties for different tasks. Some cure fast (5-minute) and others take longer. Most often, the stuff you find at Home Depot is simple 5-minute epoxy. These will work, but the problem I have with them is that they tend to be very thick. It makes it hard to pour into a knot without retaining bubbles. So this is why I like to use West Systems epoxy, although I buy very large containers and I don’t believe HD sells it. So I think your best bet is to head to HD, and look for epoxy with the longest cure time they have. Mix a little up in a small cup or dish (that you don’t care about) and then scoop it in the knot. It should self level and with any luck, you won’t have too many bubbles.

  25. Hawkeye1434 May 7, 2012

    Marc, this was an awesome video I saw it last year and packed it in my mental roladex. I started making my wife some cabinets for our new mud room, and for whatever reason she wanted them made out of Knotty Alder Wood. Once I got my stock from my lumber guys I saw it lived up to its name knotty alder they are everywhere but my wife loves the look so I found the stuff from the video and put it to use thanks for all the knowledge you have give me so far I love your site it’s one of my main references when I need to learn something new or refer to something older in the videos keep them coming we love them thanks again!

    • Mart August 13, 2012

      Would you guys use this technique for a Dark Walnut table that I am about to finish using a low luster Polymerised Tung oil ( Sutherlandwelles ) ?

      I am very unsure about how the finish will react with the epoxy….

      Cheers,

      M.

      •  

        Well the finish won’t really react at all with the epoxy. If the knots are small, then just make sure you wipe the finish off thoroughly. If you leave too much on, it will most likely stay tacky for a while. But a a little oil residue shouldn’t be a problem. I would do a sample and make sure you like the appearance of the knot after the surface is sanded and oiled.

        • Mart August 14, 2012

          Thanks for the TIP Mark.

          I will test as suggested.

          BTW this Walnut dining table is my first woodworking project.

          Another issue came up yesturday while I completed planing of my 3′x 6′ table top ( 3 individual sections ) :The planer took out small shallow chunks of Walnut in veri limited areas… This is a bummer because I wanted the table top to be as perfect as possible…

          The shop manager suggested that I use fish glue and saw dust to fix those areas…As you previously suggested for the knots I will test the “fish glue” fix on a sample with the Polimerised Tung oil.

          Do you have a better suggestion ?

          Cheers,

          M.

        •  

          That’s a tricky fix. Wood dust and glue, as well as traditional fillers, tend to look obvious over time. The wood naturally changes color but the filler patch doesn’t. So in the past, I have had some luck using CA glue alone as a filler. Since it is clear, it pretty much just exposes the wood underneath. Now how this will look with an oil finish is the question. Again, doing some tests will at least let you know what you’re in for. But definitely give CA glue a shot.

  26. Mart August 17, 2012

    Question related to the hardener… 207or 205 ??? I’m about to go to the store …

    In the vid you were using a 3 for 1 ration while mixing the epoxy.

    Mark : You were using the 207 then ?

    Thanks,

    M.

    •  

      For knots, I use 205 (fast) hardener.

      • Mart August 17, 2012

        Thanks Mark.

        Appreciated.

        Cheers,

        M.

        • Mart August 23, 2012

          Hey Mark ,

          Just to let you know I finished repairing the knots on my Walnut table using the 105/205 epoxy / Transtint Van Dyke brown and sanded to 220 and with 3 coats of Poly Tung oil man does it come out nice !

          Thanks again for all the great info.

          Cheers,

          M.

        •  

          Fantastic! Glad it worked out for you!

  27. franklin pug October 25, 2012

    Great mini! This vid was exactly the fix I needed for my project.

  28. J.T. Speelman December 21, 2012

    Great tip Marc. I use scrap pieces from a local logger and sometimes I get pieces with knot in them. I see others that use knotted wood in their project and they look great. Now I can use this tip in some of mine. Are there any epoxy products that you can recommend that are available at home centers or do you think I should just order it online? Thanks for your help.

  29. Brandon December 24, 2012

    Is it possible to mix the epoxy with some fine saw dust of the same color as your work piece, instead of using a dye? I’ve heard this concept before, but never actually put it into practice.

  30. Hi Marc,
    Any good tips to filling worm holes with the West System epoxy? I’m working a red oak table top with one good size knot and dozens of worm holes in each bookmatch.

  31. Matt April 7, 2013

    I have a coffee table made of reclaimed teak that has some butterfly keys on the underside. There is a small divot and crack over one of these from the surface side. I think there was a small void left that is caving in.

    Would injecting epoxy into the crack be a good way to stabilize this? The finish is simply hand rubbed mineral oil.

    Thanks for any tips.

  32. Clay December 5, 2013

    Hey – Thanks for your help here. It’s exactly what I was looking for… much appreciated.

  33. Hey Marc,
    I cut a slab of cedar off of a stump in a customers yard; to build a live edge stool seat. It’s 3″ thick and about 12″ diameter (more oval). Anyways, dried it in a room for 2-3 months that occasionally has a woodstove going in it. Took it out to shop, got it finished, de-barked and level at 2″ thick. It sat in shop for 2-3 weeks. I live on Pacific coast, so wet air in winter. I brought it into my house again and within 1.5 days there was a large crack in it (full thickness) starting on edge, going towards center (1/2 way to center). Is there any suggestion to fill,glue,strengthen this crack? I’m wondering if this epoxy method will work? Will it stop further cracking, or have you ever seen wood crack an epoxy joint/fill ?
    Thanks ! (love the site)
    Ace
    ** Is west system available in Canada too ?

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