I had two cutting boards blow up....

[fran tarkenton]

I made two end grain chaotic patterned cutting boards that ended up exploding under their own pressure/stress. I am relatively new to this and I am assuming they popped because I framed them all around....?? The photos are pre-disaster. They both cracked/expanded/split clear through the entire width of the board. ( If I can find a photo of the broken boards I will attach them later and edit the post.)

the walnut framed one popped after about 6 months and the thicker curly maple one popped after about 6 weeks. Both were made with totally dry wood. Obviously it's my error... Can someone explain the physics involved and why framing an end grain board results in disaster?

the thick board I was able to chop into pieces and make this wacky bowl... The other I'm going to just cut the ends off and call it good. I'd appreciate thoughts, feedback and some education. TIA!



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I dont have the photo of the maple one, but it did break more violently. It "popped" while leaning up against a kitchen wall. It had never been used or exposed to any water (the person I gave it to said it was "too nice to use"). It did have rubber feet, as well.

the walnut board also "popped" (less violently) and looks like this:

[Jebediah Eckert]

It's too bad, those were cool cutting boards. I imagine it would be like anything framed in solid wood, like a raised panel door, it needs to "float" to allow for expansion. End grain cutting boards also can blow apart from moisture. There was a post on here that after months their board blew apart from sitting on a damp counter. I usually put feet on mine to keep it up off the counter. if you can dig up that picture I'm sure somebody can figure out what the likely culprit is. Did the split follow mostly glue lines?

go Vikings!

[Robert Engel]

I am assuming they popped because I framed them all around....??

Yup. Can't do that!!
Nice looking bowl, though.

Check out MTM on youtube the guy makes some amazing cutting boards.

[Kevin Nathanson]

If they 'popped' as opposed to 'opened up' then the addition of moisture was the culprit. End grain is the 'end of the straw' for wood, so it can absorb significant moisture causing the pieces to swell, and the frame restricts it—or maybe even swells a little itself—which means the center has less space available than the space it wants to occupy, so it moves in the path of least resistance, which is by definition now the 'z' axis, and pop! If you want to frame them the center has to float, but that can lead to issues with cleanliness, etc. This is why one seldom sees cutting boards with frames.

Another factor (usually MUCH less of an issue that the one above) is the different rate at which different species of wood take up moisture and expand with it. That means that the pieces may expand at a non-uniform rate, and if there is enough disparity, cause breakage from that force. In this case though, I'm confident that the frames played much more of a role than the mix of woods.

K

[Jim Huelskoetter]

Wood expands as as relative humidity increases. But it does not expand equally in all directions. Referring to the woods orientation in a tree, the length of a board (height of the tree) stays the same, but the other dimensions ( tree radius and circumference) grow as moisture levels increase. So your frame stayed the same size as your center section grew, and something had to give.

[Leo Graywacz]

Next time seal it with epoxy to fill up the open end grain. It still might blow up.

[Marty Schlosser]

Here's my spin on this dilemma:

- First, I agree with Leo's recommendation, however I'm convinced it's still going to expand as it's nearly impossible to ensure the grain will be filled adequately to deny even the slightest bit of moisture getting in and causing expansion/contraction.

- If you want to increase your chances of success even further, have the vertical grained inner "panel" float inside the flat-grained frame and leave a 3/16" gap all around to allow for seasonal - and washing off - expansion/contraction cycles.

Next time seal it with epoxy to fill up the open end grain. It still might blow up.

[Michelle Rich]

although frames look nice, they are NOT SMART..DO NOT FRAME YOUR CUTTING BOARDS..let them expand and contract as they need to with water/moisture conditions. awesome bowl!

[Robert Engel]

Be the kind of woman that when your feet hit the ground each morning, the devil says, "oh crap she's up!"

Devil, heck.

We used to say that about grandma when we were kids!!

[Prashun Patel]

I also believe the frame is partly the culprit.

<Obvious suggestion alert>: I can't tell from the pix, but the bigger culprit may be the random orientation of the pieces within. All the pieces need to be oriented with the width of the grain running in the same direction, else each piece will constrain its neighbor. The slight skew angle pattern should be ok, but the width of each piece shouldn't be perpendicular to the width of the next one.

If you want the same look, after making sure the orientation of each piece is about in the same direction, I'd glue the side edge pieces of the frame in place then (ironically) attach the end caps as breadboard ends. That will allow the width to expand and contract. Two caveats: you may end up with gaps or overhand on the breadboard ends, so don't hope for a nice seamless look that you have now. Further, that expansion joint, by virtue of not being glued, may not be ideal for resisting bacteria.

Really cool looking design tho. Noted.

[ron david]

somethings just do not work and a lot of so called woodworker's little helper,"epoxy" won'y make it any better.
ron

[Dan Hintz]

If you insist on framing them, you need to stabilize the frame. You can either send them to someone who does this already (cheaper in the short run), or buy all of the equipment and do it yourself (chamber, vacuum pump, stabilization fluid, etc.). Note this is NOT the same thing as coating the endgrain or slathering epoxy on the board... stabilization will fill every nook and cranny internally and prevent the frame from moving.

Of course, then you might have to worry about the internal pieces pushes the frame apart when they expand...

[Bradley Gray]

Keep in mind whatever non wood you add to a cutting board will get chopped into someone's food. Not sure how toxic epoxy is when cured - Very sure I don't want to eat it or serve it.

[fran tarkenton]

Thanks to all for the feedback. Lessons learned the hard way are better remembered!

Just for a bit more clarification in the hopes it helps someone else later:
The boards were coated with 4 coats of Behlen salad bowl finish. My guess is that they were pretty well sealed. Maybe not as well as epoxy would do it, but pretty well sealed.
I actually contemplated floating the panel when I built them but the cleanliness factors made me think twice. And I figured since they were relatively small pieces, they wouldnt expand too much (WRONG!)
Neither board was ever actually used. Never subjected to a knife or a washing. They both had feet and just popped. Neither was a gradual event, per se. Both times, a loud "POP" was heard.

Stabilizing the frame pieces in a vacuum chamber (like giant pen blanks) sounds promising. That's a very interesting proposition. If I ever get that kind of set up, I think I'll give that a shot.

Thanks again!

[ron david]

it is not that they are small pieces. each small piece may move a small little bit. it is when they add up it changes things. take a penny; it is worthless in itself as a penny. put a million of them in your pocket and you have a force to do a lot of things.
it does all come down to one thing though, experience.
ron