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!

What Happened?

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 Epoxy Fix:

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!

This week’s project, or more accurately projects, come from four young skilled craftsmen: (from left to right) Jordon, Joe, Sheldon, and Stephen. The picture was submitted by their shop teacher, Jarred. Now I get quite a few emails from shop teachers who use our videos in their classes, and each and every story warms my heart. But this is the first time someone actually sent a picture. I thought it was so cool and that these guys did such a great job, that I would post it as our Project of the Week. I know I may have presented the end grain cutting board as a “great beginners project”, but those of you who have made one will agree with me that it is by no means easy. It’s a testament to Jarred’s teaching ability and the personal skill of each one of the guys that their boards look as good as they do!

Here’s what Jarred had to say:

I teach a shop class in rural Wisconsin, and took the initiative to introduce the boys to The Wood Whisperer (someone younger and cooler than me). I walked them through the cutting board project, but showing them your videos. Every time I fired up the laptop they would in unison say, “Let’s get ready to make a cutting board!” Anyway, here’s a picture of a few of them and their cutting boards: combinations of walnut, maple, and purpleheart. The boys had fun with the project and gave the cutting boards as gifts for Mother’s Day.

Ok so I am generalizing here for fun, but you get the picture. I have noticed as well that many of the people posing these questions may be doing so because of my advice from Episode 7- A Cut Above. To sum up, I said that my favorite finish for end grain butcher blocks is salad bowl finish (aka varnish). But remember my caveat. I said we are NOT trying to build a film. And that’s exactly what the folks in the forums are trying to say. If you build a film, the film will then be cut by a knife. The cut will allow moisture to seep under the finish and become a wonderful home for all kinds of bacteria. I can’t disagree there. But with my method, you never actually build an appreciable film.

I recommend diluting the finish sufficiently so that it immediately gets absorbed into the wood’s wide open pores. Think of it like a vertical bunch of straws that you are filling up with finish. Within a minute or two, you will notice that finish is actually seeping out of the bottom of the board. This is exactly what we want. At this point, I usually set board on its side and allow it to dry overnight. I do this 3-4 times with a light sanding in between each session. By the final coat, you should start noticing that the finish doesn’t really absorb any more. You are now starting to develop a film. One last wipe with a clean cloth and call it DONE.

So how does a board like this fare in the kitchen? There are two main concerns here: safety and maintenance. A butcher block treated this way will resist water all day long. In fact, on my boards, water tends to evaporate faster than it absorbs. Mineral oil boards will actually take on moisture much more readily. Adding wax to your mineral oil can certainly help in this area if thats the route you want to go. Now the fact that it is so water resistant is a major plus in terms of sanitation. Remember that the bacteria like the moisture. So the less moisture in the board, the better.

So how about knife marks? Well like with any board, knife marks will happen. If they don’t, you must not be using your board properly. So what happens to my boards? They get knicked up. They get dulled a little more in the middle where the most action occurs. But after about 18 straight months of usage, my cutting board looks pretty darn good. Check out the pics below. Now if there were a thick film on that board and that film were to crack, the moisture would certainly seep in and create problems. In fact after 18 months of that type of abuse you would probably expect the finish to start flaking off or exhibit more physical damage than what you see. But when a knife produces a deep cut on my board, it just cuts into varnish-filled pores. There is nothing to flake off.

Now let’s talk about maintenance. I haven’t done anything to that board other than a light soap and water scrub after each use, and an occasional white vinegar rub down. And I suspect that in another month or so, I will take the board back in the shop, give the top a nice thorough sanding, reapply a light coat or two of diluted varnish (monitoring how much it takes up), and the board will look brand new. What kind of maintenance does a mineral oil board require? Monthly, and possibly more frequently if used heavily. Maybe I’m just lazy but one of those maintenance schedules sounds a whole lot more fun than the other.

I am by no means trying to discourage people from using mineral oil. After all, its the classic cutting board finish. Use whatever floats your boat. Personally, I have had great success with my method and will continue to use it. The feedback from other folks who have tried it has been great as well. I think its safer, easier, and looks better. Of course my results are not backed by scientific tests. If I still worked in a lab I might be able to test it properly. But I can’t, so all I can do is speculate and bring a little common sense to the table. Finishing is, and probably always will be, one of the most over-complicated and misunderstood areas of woodworking. I only wish there were more scientific resources out there so that issues like this can be resolved effectively without speculation. Until then, do your research and never count on my advice or anyone else’s as cold hard fact. Gather as much information as possible from your trusted resources and then add the final ingredient: YOUR experience, opinions, and common sense.

Viva La Varnished Board!