7 Common Problems With End Grain Cutting Boards
End grain cutting boards are fantastic bits of kit for the kitchen and if made correctly will last decades, but there are a few common issues that people have when the time comes to make a board and/or put that new board into use. This article is a list of the 7 most common mistakes I know that are made when making end grain boards, and after 25 years as a woodworker and 30 years as a professional carpenter I have made a few of them myself. I am no expert on many things, but with end grain cutting boards, this is what I know.
The top seven problems with end grain boards.
- The board is to thin.
- The board has been allowed to dry out.
- When made the wood was not dry enough.
- When made the cuts were not square in the board joints.
- The grain orientation is mixed.
- The Wrong type of glue was used.
- There is no spacer under the board to allow for air flow.
Lets go into each of these items individually and see if we can work out how to approach them either when making the board or when using one over time.
What thickness should an end grain cutting board be.
There are discussions online regarding the optimum thickness for an end grain board, and to get some sort of an idea on how to address this issue, we should use some logic. In another article I have mentioned that end grain is how you chop firewood. Think about a foot long block standing on its end and the force required to split it with an axe. Now think about the block being 6” long and standing on its end waiting for the chop. The energy required to split the smaller block is far less than the longer one, and this is the issue with end grain cutting boards.
If they are made too thin there is an increasing chance that the board will split if dropped or treated roughly. If the board is made too thick the weight makes the board hard to move around the kitchen and while it will be far more stable it will not be used much because its so damn heavy.
So they are the two outcomes, either too thin and open to breakage, or too thick and far too heavy.
But is there middle ground? Yes there is and it is not a single measurement. What has to be considered in this measurement is the grain structure of the wood being used in the board and how easily it splits along the grain.
This should be known before the board is made. If the wood splits very easily this is the signal to make that board slightly thicker than average.
If the wood grain is interlocked and fights against splitting this wood can be on the thinner side of the average.
What is the average? This is for the woodworker to work out before building the board, and is derived from the wood species that are likely to be used when making the cutting boards.
The first step is to take an offcut from all woods available and cut them at 1 1/2” long along the grain so they stand up at 1 1/2” high as end grain. Take a chisel and split the wood vertically just as the firewood is split. If the wood fights then it can be safe to call this the high value for this wood.
If the wood splits easily then mark this measurement as the low end for that wood. It will take a little time to work through the woods you have available but in the end you should have a low and a high value for each wood. When it comes to putting a board together it is rare that a single species is used, so to work out the average for that board just add the highs and the lows of each species together and divide by how many units of wood there are.
This will give you the average depth for that particular board and I recommend this being the minimum thickness.
This section is all about the making of the boards so already being an owner of an end grain cutting board is just luck of the draw really and you are relying on the skills and knowledge of the maker to have done the homework.
Why is my End Grain Board cupping and how can I fix it.
The end grain cutting boards biggest weakness is the users lack of understanding of the boards needs and this therefore leads to a lack of maintenance.
End grain boards cup or warp because of moisture. To be more precise it is an uneven amount of moisture on both faces. Moisture and end grain boards are compatible only if the grain is kept loaded with a water repellant coating that penetrates into the end grain. If this water repellant is not present the water will enter the end grain and cause swelling of the wood fibers.
If this happens on just one side the board will cup. If it happens on both sides simultaneously the board may cup but it will still swell. Wood will always do this no matter the application. It happens with furniture, wood strip flooring, and the end grain cutting board.
The process of keeping moisture at bay starts at the making of the board. When all the cutting, machining, gluing and sanding is complete, the board should have a generous application of food grade oil that is runny (thin) enough to soak into the middle of the board. Food grade mineral oil is great for this.
The next step is to try and lock this oily moisture into the middle of the board and this can be done with a blend of the same oil and beeswax. This is applied and rubbed into the grain ends. Several applications can take place before the wood is full and protected. A light wipe down or buff is all that should be required to have the board ready for use in the kitchen.
For the owner of an end grain board, it is advised to find someone local who makes this blend, board makers often have tins available for sale, and get yourself a tin. How often you apply the blend is related to how often you use the board. The board conditioner (oil/wax blend) is not expensive so be generous with the regularity and the board will last for a very long time.
An indication of the board needing a treatment is when washing down the board the water doesn’t bead and run off anymore. It is important to keep this water barrier up to standard. The method of straightening a warped end grain cutting board, it is often a simple task of applying a damp cloth over the dry face for a period of time and this will depend on how moist the side that cupped actually is.
This method allows the wood to balance the moisture levels on both faces and should take out the cup. The board should then be left to dry completely for several days. Apply several coats of the oil-wax conditioner to both sides.
The wood used to make the board was not dry enough.
This problem happens when the novice woodworker starts getting excited and grabs any wood that is available to make the board. When wood is still wet from being milled it carries two types of water within the wood. There is free water and this is the first type of moisture to leave the wood. The other type of water is bound water and this is more difficult to remove.
This is the moisture that is left after kiln drying and is often stated as a percentage of moisture content. If the wood to be used is not to be kiln dried, it is said to be air dried, and this process takes far longer that the kiln process. How this relates to the end grain cutting board is that if there is still free water locked up within the wood, it will create a barrier for the oil/wax blend to work its magic.
Over time, this water may make its way out of the wood and this may, under certain circumstances, allow the wood to dry out and be exposed to water penetration after the board is in use. This drying out after being made also may cause the wood to move and either cup or twist within the board. This can place stress on the glue joints and can cause splitting in bad cases.
So having said all of that, it comes down to best practices when handling wood that is to be glued and made into items. Dry wood is far more stable. Don’t try to reinvent the wheel. Use dry wood.
This section is another where the owner of an existing board is left wondering if they have a suspect board. The best way to counter this thought or suspicion is to be proactive with the board conditioner and never allow the board to dry out.
Are square cuts needed for end grain cutting boards.
This is a section purely for the craftsperson as it entails accuracy while the end grain board is under production. The call for quality cuts is not just because it is what a quality maker should be doing because there are structural reasons why this is required.
For an end grain board to survive the trials of typical kitchen use over an extended period that could be decades long, best practices must be maintained while the board is being made and this includes accurate cuts that give a tight fit to both faces of the board.
The primary reason I state this is because the glue joint will react differently between the thin end and the thick end if the glue thickness between the wood pieces differs.
Glues are designed for an optimum thickness that can be relied on to do what the glue manufacturer states.
When the glue is applied outside of this optimum thickness there is the chance of excess wood movement because the larger glue join allows for this movement. That can cause warping or twisting because the original cuts are poor.
Clamping pressure will not cure a poor cut, nor will more glue be sufficient to fill the gap. Poor board performance is the risk if this process is ignored, and while the board may function just fine, the risk is most definitely there and should be recognized.
For the board owner with a poorly made board please be aware that the issue is likely not an end grain boards are all bad scenario but more of a poor workmanship event.
Can grain direction cause problems with end grain cutting boards.
There are several good research papers that go into detail regarding this subject and I will link to one at the end of this section.* When a log is milled the miller selects the cuts to make to optimize the yield from that log.
It could be quarter cuts, plain cuts, rift sawn or any mixture of them. Every type of cut reacts in its own unique way when drying from milling, and when the wood is selected and incorporated into a product. It could be a table, a set of chairs, a dresser, or a simple end grain cutting board.
The grain orientation will dictate how that piece of wood will react if moisture is allowed to interact with it and understanding the likely reaction is part of the mystery of woodworking and is something that is learned over years of practice and actually seeing it happen before your own eyes.
The key phrase in this section is if moisture is allowed to interact. Grain orientation can be managed and should not be an issue if moisture (water) is kept at bay, and this requires diligent maintenance on the part of the board owner and user.
Link Here or copy/paste link below.
* https://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch03.pdf
What glue is best for end grain cutting boards.
I will state right up front that I recommend Titebond 3. Many experienced woodworkers have had good success with titebond 2 so I will leave it up to you as to your choice. It is not recommended to use epoxies or urethanes as there are questions regarding food contact that raise concerns.
Both the titebonds are rated for indirect contact with food and so are premium glues to consider.
How I approach this is I prefer to have just the one glue for as many processes as possible and as I do quite a bit of segmented turning as well as end grain cutting boards titebond 3 serves my purposes very well.
Could I use another glue? Of course I could, but I like the open working time that 3 gives me, I like the waterproof qualities, and the food contact tick of approval is the cherry on top.
Owners of end grain cutting boards might want to find out from the maker what glue was used just in case. It is the ability to talk with the custom board maker about these kinds of things that make buying from a small shop so worthwhile. Support the small shops where you can, you are likely to get a premium product.
Does an end grain cutting board need rubber feet under it.
This is a must have, in my opinion. The simple process of fitting small rubber pads to the underside of the end grain board does a few things that seem insignificant until you understand just how good they really are, and how little they actually cost.
The first benefit is a gap for airflow. It is not so much a need to have air flowing but more to create an air-gap to stop moisture from sitting under the board and soaking into the underside of the board.
If the board has nothing to create a gap and the board is allowed to sit in a small pool of moisture that is trapped between the bench top even if the board is well looked after with an oil/wax blend the moisture will still find a way into the board and it will likely cup and warp.
It can be a simple overnight process and may cause cracks and splits in extreme cases.
The second benefit for feet under the board is for grip. There is something comforting when using a cutting board when it stays where you place it and you don’t have to chase it around the kitchen as you prepare the evening meal. The feet also allow the fingers to get a grip on the board when its time for cleanup.
For existing owners of boards, if there are no feet fitted to your cutting board it is a simple process to screw one on each corner of the underside. Use stainless steel screws and pre-drill if possible.
So in conclusion I hope that there are some snippets of value in the article above for anyone who has made a board and had problems, or the article helps the owner of a board that is doing weird things on the bench top. There is a simple reason why end grain cutting boards warp and split, and 9 out of 10 times it is moisture related. Understand how this happens then remove the risk and your boards will last for years.
Article written and edited by Tim Blanch as owner and operator of Woodwork Hobby Report.