A few months ago, I woke up one morning, poured my coffee, and was incredibly disappointed to see that my cutting board exploded! OK so maybe it wasn’t all that violent but it was cupped like crazy and had a very large split. Upon further inspection, I noticed a bit of trapped water in the center of the underside of the board. Now the thing to remember about end grain cutting boards is that even after finishing, they will still soak up moisture like a sponge. So standing water is your cutting board’s Kryptonite!
So how does the split actually occur? Well let’s think about what happened. The water soaked into the center of the board and as a result, the center “squares” swelled and expanded. Because the moisture was in the center only, the wood in the outer perimeter did not expand. So something had to give. The resulting crack is really nothing more than pressure relief. Think of it like surrounding a piece of solid wood in a frame. Eventually, the joints in the outer frame will open up if the board in the middle expands.
The first step in repairing this disaster simply involves waiting. After a few weeks, the board flattened out and the crack closed up almost completely. But the gap was still big enough that I wanted to use a gap-filling glue, so epoxy did the trick. Now I know what you are thinking. Is epoxy food-safe? While I have heard that food grade FDA-approved epoxies do exist, I have never seen them. And I can definitely say that the West System Epoxy I use is not FDA-approved. So why would I use this on my cutting board? Generally speaking, its the same logic I subscribe to when discussing the safety of film finishes. That is, once cured, the product is inert. In other words, its not chemically reactive and its not actively leaching chemicals under normal room temperature conditions. Furthermore, the crack represents such a small area that actual food contact would be absolutely minimal. Now while I am not prepared to tell you epoxy is completely food-safe, I will say that I consider cured epoxy safe enough to use on a small crack on MY cutting board. Ultimately, the final decision is yours.
Want to make an end-grain cutting board like this? Check this out!