This week’s question comes from Tony, he’s experiencing a rather common phenomenon with his cutting board. Let’s see what he has to say:
I recently made one of your cutting boards as described in Episode 7 – A Cut Above. No problems with the manufacturing or finishing process. I gave this as a present to somebody and about a week later they returned it to me. The board had bowed & buckled in the center, about 5/16″ (big central high spot on one side, and depression on the other. The board was made from Jatoba and Beech, using a water proof PVA glue. OK I thought, maybe the dissimilarity in the woods was too great (beech SG64 & Jatoba about SG80), so I have just made another board this time using Beech and Walnut and using a polyurethane glue. Whilst belt sanding I noticed that this board is also starting to buckle the same way the first board did (1/8″). It is now being clamped and flattened again. I was wondering if you had ever come across this type of problem before? All the timber is kiln dried and between 6-8% , the only common factor between the two boards is the use of Beech, but I have been using this batch of lumber for other projects without any problems.
And here was my reply:
Hey Tony. It should ease your mind to know that this happens all the time. There are many reasons for it. Moisture, jointing inaccuracy, and of course, the X factor just to name a few. In many cases, these boards cup for no logical reason. The good thing is they can be straightened out to some degree. If you have a cup, you can overclamp it slightly the other way to straighten it out. Also keep in mind these boards will move a lot over the coarse of time depending on their usage and the way they are cleaned and dried (be sure the user is drying the board on its side). In fact, last week my board had a 1/8″ cup to it after cutting a hot piece of meat. I just checked it today and its nearly flat again. Now with any luck, when your board develops a cup, it will face down (looks like a frown). This way the board remains nice and stable on the counter top. If it goes the other way it will spin. So you may want to put the boards in the reverse clamp for a week or so. Don’t be afraid to spray the board down with a little water before you throw it into the clamps. That will help to “reset the memory” of the board. Then hope for the best. As long as the board is sitting with the cup down, 1/8″ is really nothing to worry about. Wood generally does not want to stay perfectly flat all the time. And from what I understand, most pro chefs put their boards on towels to stop them from moving around. So it’s pretty much the nature of the beast. If your recipient wants something perfectly flat, I recommend plastic. :) Good luck!