A well-built cutting board can be one of a cook’s best friends. But even a solidly constructed board is not indestructible. Splits are usually caused by moisture issues that lead to warping or curvature of the surface of the cutting board. Warping can be the result of a board that dries out completely, or one that has been allowed to remain wet for too long. Although many splits require you to replace the board entirely, sometimes you can repair the damage.
Sand the entire surface of the board with sandpaper to remove any finish application. Use a 36-grit paper to remove the glossy finish followed by a second pass with 60-grit paper to smooth out the wood surface.
Remove any warped areas in the wood by placing the cutting board on a flat surface to note any rises and falls. Place a wet cloth on any portion of the board that rises above a level plane. Turn a steam iron on to its maximum setting, and place onto the bump of the board. Apply pressure to the rise in the wood, pushing it downward in an effort to remove the warped area.
Drill 1-inch-deep holes into the sides of the board where it has split every 2 inches, extending along the length of the split. Drill the holes in both boards so that when placed together at the split the holes in the corresponding boards match evenly. Holes should be about one-quarter the size of the board’s thickness.
Cut wooden dowels large enough to fit snugly into the drilled holes into 2-inch-long pieces—enough to fill the number of holes in the side of the cutting board.
Place glue along one-half of each dowel, and press it into one of the split halves of the cutting board, firmly seating the dowel into place.
Glue the other halves of the dowels, along with the half of the board edge containing the installed dowels. Slip the other board half onto the dowels, until the two split halves meet snugly. Tap the board halves with a rubber headed mallet, if necessary, for a tight fit.
Clamp the board edges together until the glue dries for the length of time prescribed by the manufacturer.
Sand the boards smooth, removing any excess glue along the seam between the board halves. Use three passes with the sandpaper, this time with a 60-grit, followed by an 80-grit, and ending with a 100-grit paper. Each pass should leave you with a successively smoother surface on the wood.
Apply a layer of mineral oil to the surface of the board with a sponge to prevent drying, which will help avoid further splits.