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Oct 19, 2009 04:12 PM

how to fix a warped cutting board?

I have an end-grain Boos cutting board which warped, making it concave, with the corners curved slightly upwards. Was wondering if anyone knew of any tricks to fix it and make it straight again? Was hoping there was a way by applying water or oil to either the edges or center to help it along, but don't know how. Any suggestions?

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  1. Steam is used to shape wood - maybe you could set up a vaporizer and the board (on a rack so all surfaces are exposed) inside a sealed plastic bag. Then, when the moisture has thoroughly permeated the wood, take out the board and wrap it in a towel, place it concave side down, then weigh it down with as much as you can: bricks, cinder blocks, books, etc., and leave it for at least several days, maybe a week. And be sure not to let it get very wet in the future, since that most likely caused the warping.

    2 Replies
    1. re: greygarious

      That might work for a long-grain block, but if you try it with an end-grain block made of many glued pieces you will probably crack it beyond repair. Take it to a cabinet maker or a carpenter who has a planer big enough to handle the board and have it planed true and sanded.

      I'm curious. How did you manage to warp a good quality end-grain board? Those things are 2-3 inches thick!

      1. re: Zeldog

        Thickness has nothing to do with whether wood will warp. Unbalanced absorption of water will warp any board.

    2. Boos is overrated if you ask me. Anyway, many one piece cutting board warp when only used on one side repeatedly. Basically, water and mositure continue to enter the wood board on one surface, so that surface expands faster than the other side and thus the board warps. In this case, you can always weights it down if the warping is very minor. If the warping is bad, then start to use the other side or water the other side slow and it will warp back somewhat but it won't be perfectly flat. At this point, put something very heavy and flat to force the board flat and let the whole thing dries.

      In your case, I am guessing you bought the end grain cutting board pieced by numerous wood block. In this case, the warpping may occur the way I described, but that tends to warp the opposite direction you mention. Does your board has feets? Is it possible that water gathered on the underside?

      If you can attach a photo of your board, it may help. Thanks.

      1. Your board warped because: 1. The board was allowed to sit in a small bit of water which made the wood fibers expand; 2. There was a small amount of moisture that was allowed to sit on the top cutting surface; 3. When you oiled it you didn't oil all the surfaces evenly.

        What to do: You can try to stand the board up on its end for several days to allow the moisture levels to even out on the larger surfaces. You can apply a small amount of moisture to the convex side to make it even out. Or you can do nothing and simply learn to live with it.

        If you take it to a commercial cabinet shop, they will most likely not let you run it through a planer because an end grain board will destroy expensive planer knives and the applies oils and fats from meats will clog and ruin a wide sanding belt. If you have a friend who has a planer, try them but be prepared to pay for some blades and still do a lot of sanding. If you have a friend with a wide drum sander try them. But you will have to replace the sanding belts often because they will clog. Using heavy weights will not work. This may force the board back to some form of flat but it will return to the warped position soon after.

        My advice? Try the easiest first, standing on an end or side, and then go from there. Good Luck.

        1 Reply
        1. re: BoardSMITH

          No, the convex side is the side that got wet.

        2. I did the below with a wet towel vs. grass, on top of the refigerator whcih gives off ambiant heat. It worked perfectly:

          To unwarp a board, work in summer. The traditional cure is exposure to wet grass and hot sun. Water a grassy area thoroughly, and set the board curved side up on the wet grass. As the dry side of the board absorbs moisture from the grass, the moist side -- the convex side -- is dried out by the sun, and the board unwarps. Unless the warp is caused by stress in the wood, the board should straighten out within a day.

          When the board has straightened out, clamp it between two straight boards so that it will dry evenly. From there, oil often with neutral, food-safe oils.

          4 Replies
            1. re: sr44

              if the board is warped... it typically curved concave.. because one side got more moisture than the other.

              1. re: davidf44

                Yes, but do you put the concave side up or the convex one?

                1. re: sr44

                  I agree, bunch of mumbo jumbo. Concave side down toward moisture, convex side up.

          1. All the suggestions given will work to some degree. Unfortunately for me I had the same problem and I have never been able to fix my board completely. Oiling one side, leaving it in the sun, wrapping it in plastic, etc etc, have all helped my Boos worktop slightly, but as soon as I stop saturating one side in oil it bends back again. I paid $500 for a hundred pound piece of crap (which came to me already bent) that has been in my kitchen for five years and still bounces up and down when I use it on top of a flat stainless steel table. I will never buy a Boos product again for as long as I live.


            4 Replies
            1. re: la2tokyo

              All cutting boards warp to some degree and rarely remain perfectly flat. if it's portable most professionals place the board on a towel when cutting so there's no movement.

              If yopu have a 100lb $500 Boos cutting table it probably is a great cutting table... they're not meant to be sitting on them. :-)

              You eman like this one?

              1. re: davidf44

                You can read the details in my thread. The board was almost 1/2" warped when I received it. It is not a table like the one in your picture, but rather a reversible bakers table top. If I wanted to stabilize it with a towel I would have to use two bath towels and that still wouldn't fix the problem of it not being flat. I originally purchased it it to roll out dough, and the middle of the board still has a 1/4" concave dish on one side, so when I roll dough out with a rolling pin (which is dead straight) the dough is 1/4" thicker in the middle than it is on the edges (or 1/4" thinner if I flip the board over). Anyone that thinks that just because it is a $500 Boos product that it's a "great cutting table" can message me and buy it for half price. As for my opinion, I believe 20 years of professional cooking experience which includes working in a 3-star Michelin setting should qualify me to judge a product I use every day as defective. I've used wooden cutting boards my entire life and I've only had one that warped. I would have never complained about it if it was flat when I received it, but for them to ship it to me and expect me to spend months trying to get a 5/16" twist out of it is ridiculous. If the OP's board was flat when he received it, most likely he can fix it, but I have personal experience with a Boos product that had a large amount of twist and stress built into it, which cannot not be corrected by anything except a huge surface planer.

              2. re: la2tokyo

                If you make a flattening jig using a router, you can fix it perfectly.The thickness will decrease some.

                1. re: la2tokyo

                  I have the same problem with my expensive Boos Board. I leave mine out on my cabinet top all the time, as it is handy. Some how moisture must have gotten under it. I placed a (dry Terry) towel on the cabinet, then the Boos board over the towel. I have always been careful. I use the Boos oil. I clean with Lemon and salt. Still I am so disappointed. I have had cheap boards that did better then this.