Need a Hand: Cutting Board Failure

[Brody Goodwine]

Well, I just presented my first cutting board to my mother, only to have it severely warp and split 4 hours later after being wiped down with a wet towel. The board is end grain walnut and hard maple. Glue was titebond 3. Finish was 3 coats of general finishes poly acrylic with sanding between coats.

I suspect some water still penetrated the finish based upon the slowish drying. It has feet and was not laid in water. I feel like there must have been some major internal streeses based upon the severity of the split. Any ideas what exactly caused the split?

[Brody Goodwine]

Finished


Split


Turned as Well

[Ted Calver]

Brody, No expert, but I think the poly is a film forming finish and your suspicions are right. For cutting boards a penetrating finish like mineral or walnut oil, or butcher block oil is better and keeps water from getting wicked up by the end grain. If all your stock was dry and straight from the beginning and your glue was from a fresh batch, water penetrating a surface finish might be the culprit.

[Brian Kent]

I agree with Ted. Mineral oil soaked in many times is the finish for a cutting board.

[Todd Burch]

From what it looks like, the end grain wicked up the water (probably just like it wicked up the finish), expanded, and POP goes the glue joint.

I would not have used poly acrylic, but mineral oil only.

Does the split glue joint appear to be starved for glue? Were any surfaces in the split joint void of dried glue?

Next time... you can glue in some some hidden splines/loose tenons between each block and around the interior of the outer perimeter. Sorry this one split. Your next one will be better, I'm certain.

This one is probably still fixable. Before I did anything with this one, I would give it the "smoke test" and slam it down on a hard surface, flat, to see what else might be thinking about letting go.

To fix, break the joint the rest of the way, let it dry, clean up the joint, mortise for a spline on both halves (just shy of each end, so it will be hidden), make a spline to fit, and re-glue with spline. Sand, and liberally oil both sides, several times, until it won't soak up any more oil.

Todd

[Bud Millis]

Having made several thousand boards over the last 20 yrs, here's my thoughts:

1. glue failure
2. On the very first picture, there looks to be a half dozen gaps in the maple. That can allow moisture, etc to get into the board - not good.
3. Grain orientation - might be an issue - hard to tell from the photos - walnut on the sides doesn't look to match the maple.
4. (side view) Maybe its just the picture, but the board doesn't look to be of equal thickness.
5. Was the board left to soak in H2O?
6. I only use Titebond 1 or Elmer's
7. Never use poly acrylic (flakes, won't hold up, food safe??) or walnut oil (turns rancid on board over time). I only use Salad bowl oil finish (rarely) that's d/t the fact that it coats the wood and when used as a cutting/chopping surface it flakes off. The best is mineral oil and bees wax heated up and applied. It gives a great finish, easy to maintain, the heated oil soaks deeper into the wood and the wax helps to fill any voids and won't promote bacterial growth.

Repair -
1. let it dry good
2. rip a hair off each side (square table saw blade + a good blade = good glue joint)
3. use the glue(s) I stated and glue both sides
4. clamp well - allow to dry overnight
(if those are gaps in the board, use 12 hour epoxy, and maple dust to it and fill the holes. you may have to add to it a couple of times, as 12 hr epoxy is thin and will run into the gaps. which is what we want)
5. clean up glue joint
6. sand entire board - rid yourself of the poly crap (its my opinion and I feel there are a lot better, more natural, safer products available which will produce the same if not better results)
7. mineral oil + bees wax (60/40) heat on stove till its in liquid form and apply. just slop it on, its cheap. about an hour later I may apply a second coat if it looks like it sucked it up. let dry 6 hrs/overnight and buff with clean dry cloth. DO ALL sides

depending on use, reapply mineral oil + bees wax on a prn basis.

NEVER allow a board to soak in H2O, or enter into the dishwasher.

[geoff wood]

i think it has nothing to do with what finish you used. maple moves a lot more than walnut does, if walnut was the inside wood then you might not have had a failure so quickly. it looks like the grain of the walnut isnt parallel to the edge of the board, rather its dying into the corners. risky when it comes to wood movement.

[Art Mulder]

For cutting boards a penetrating finish like mineral or walnut oil, or butcher block oil is better

Or no finish at all.

For a working cutting board, I'm in the "no finish at all" camp.

Well, I just presented my first cutting board to my mother, only to have it severely warp and split 4 hours later after being wiped down with a wet towel.

You've already been well guided. Are you 100% sure it was only wiped with the towel, and not left to soak in it? I only ask because the 2nd photo looks VERY different in terms of the finish.

Call it a learning experience and try again.

[Brody Goodwine]

Thanks everyone for the forensic work. I would like to save this one. It is back home and has markedly flattened with drying. The crack is also about 50% of what is shown in the pics now.

Finish: I didn't choose mineral oil mainly bc it darkened the board so much. My mother even noted after it cracked that she still wanted it refinished with something that wouldn't make it dark. Who am I to argue? I tested min oil (too dark), salad bowl finish (flakes when cut and dark), and poly (neither issue). I thought poly would provide a superior seal as well? Am i mistaken there? Could the end grain just have needed more coats, or would no number of coats seal the board?

The board did have some fine gaps in the Maple, which i later filled. The glue joint also looked a bit dry despite feeling like I was liberal with it during assembly. Both likely played a part.

Besides the finish, my other big question was grain orientation. All grain (maple and walnut) was oriented the same. Does that improve or decrease dimensional stability? The amount of twist was impressive, and I wasn't sure if there was a layout error.

[Ray Chalenski]

Nice idea for the cutting board.You got some great advice from others.Any cutting board I make I'll treat with mineral oil. The only other observation I can make is I've used titebond 3 on several occasions and was never happy with the results.Always had a failure. Went back to titebond 2 and never looked back.

[Todd Burch]

Paint some poly on a piece of glass. Let it dry. Chip it off and offer some to your mom and you both sit down and eat the chips.

If you don't want to do this, don't coat the cutting board with poly. Get over the darkening of the wood. I mean, seriously, how dark does Maple get with clear oil on it? Face grain would not get as dark, because it won't soak up as much oil as end grain.

Todd

[Jim Becker]

Brody, you actually don't want a "seal" on this kind of project which is why folks are saying not to use a film finish. It needs to breath. Mineral oil is generally the product of choice for this application with many folks also opting for a combination of melted paraffin and mineral oil.

That said, Geoff makes an excellent point about the potential incompatibility of species when it comes to wood movement. Maple moves a lot seasonally, not to mention with the artificial moisture environment you find with kitchen use.

[Ted Calver]

I thought poly would provide a superior seal as well? Am i mistaken there? Could the end grain just have needed more coats, or would no number of coats seal the board?

Sure, poly will seal the board. Probably 5-8 coats of wipe on would do the trick. Then your mom could prop it up against the back splash and brag to her friends on your wood skills--she just couldn't use it as a cutting board. It might last a few times slicing a loaf of fresh bread, then the poly film would get sliced and when the board got washed water would get behind the film and soon it would look yucky. Then you could refinish it again. Groundhog day style

[ian maybury]

Did it by any chance take a trip through a dish washer? The whitish look is very like what they often produce on wooden parts. No expert, and based solely on casual observation - but there's little or nothing wood that will survive that....

ian

[Howard Acheson]

You have at least two problems. First, your construction method created a cross grain situation. The long blocks at the end that span two blocks caused the warp as soon as it got wet. ALL blocks need to be the same size to insure that unequal stresses are not created when the board reacts to moisture.

Second, you never want to use a film finish on a butcher block construction. That will create uneven absorption of moisture resulting in uneven expansion/contraction. No finish will prevent the absorption of water or water vapor--it only slows it down somewhat.


An excellent treatment for wooden food preparation surfaces like cutting boards and butcher blocks is a mixture of mineral oil and either paraffin or beeswax. This is what is used on many commercial wood surfaces. It will last longer and be more protective than just mineral oil. Mineral oil can be found in most supermarkets in the pharmacy section or in a true pharmacy. Paraffin is found in the canning section of the store or in a hardware store.

Heat the oil in a double boiler and shave in some wax. The exact proportions are not critical--a 5-6 parts of oil to one part of wax will work fine. Stir the mixture until all the wax is liquefied. Apply the mixture heavily and let it set 10-12 hours or overnight. Next day do it again and continue until the wood will no longer absorb the finish. Let it set for 10-12 hours and then lightly scrape off any excess. Then buff it with a rag.

Reapply whenever the wood begins to look dry.

Never put a wood board in the dishwasher and don't soak it in dishwater for long periods.

There is probably nothing that can be done to save the board at this point.