cutting board bowing issues

[Bryan Naber]

I recently made some edge grain cutting boards and finished them with 2 coats of mineral oil. The problem after washing the cutting board by hand it starts to bow and broke some of the glue joints. What happened and why? This is how I built them

1. edge glued my stock together.
2. cut glued up piece into 1 1/4 lengths.
3. turned the 1 1/4" lengths so edge grains were up and down and glued.
4. drum sanded both sides and looks good now. Its all flat now.
5. bumpers on the bottom and 2 coats of mineral oil top and bottom.

After a couple of washes it bowed bad and crack. Once it dried it went back to normal. I would like to make more but want to fix this problem.

[Matt Day]

Some of it is just the nature of the beast - wood moves with moisture. Others will chime in, but I think end grain boards are less suceptable to bowing. Thicker is usually better too.

When you wash it, don't submerge it under water but just scrub it down then dry it as soon as you can.

[David Winer]

Wet both sides each time a cutting board gets wet. Then either dry both sides or leave wet to dry evenly.

[Dan Forman]

Watch this video about finishing:

file:///Users/danforman/Desktop/new%20woodworking/charles%20neil%20you%20tube/www.youtube.com:watch%3Fv=xq2pb_LfOBo.webloc

[Chris Ricker]

Bryan;
I've made many of these cutting boards and finished with mineral oil, none have bowed(that I know of)
Maybe the problem is not enough mineral oil?
I usually coat the board thoroughly, I mean several days worth on both sides.
I could see the boards bowing if the mineral oil doesn't saturate deep enough.
good luck!

[Kent A Bathurst]

5. bumpers on the bottom and 2 coats of mineral oil top and bottom.

After a couple of washes it bowed bad and crack....

Coupla things might be going on, from my experience.

First - it takes longer than you might think for everything to settle out after cutting, gluing, and mineral oil. It will sag - WILL sag - where the gap is between the bumpers. I don't use them anymore for that reason. I'd guess that this all stops after a while, but don't know.

Next - even without the bumpers, the ones I made would bow a bit after washing. Stopped after a few months, but still - yikes. Turn it upside down for a while and it will level back out.

Next - wood species? My references are all relatign to hard maple. Something less stable would prolly exhibit more of this.

Next - "washing" - that should be nothing more than squirt some liquid dish soap on the surface, scrub it a bit, rinse thoroughly, dry with towel, and then let it sit ON AN EDGE - not the flat surface. Do NOT immerse in a sink full of water (other than for a very few seconds, perhaps).

Last - cracks - you might not want to read this......You have to rotate the blocks during glue up so that the grain on adjacent pieces does not run parallel - they have to be at (ideally) 90*, or in that general direction. If not, over time (up to a year) the expansion + contraciton will cause the glue joints to be pulled apart. 4 sets of two (large and small) for me and neighbors - Five had this problem and had to be repaired. Bummer on a big scale, because I was sure I had done it all correctly, and they were washed and dried correctly. I stumbled across the cause and solution in a FWW article by a guy that makes end-grain butcher-block coffee tables.

[Bryan Naber]

Thanks for all of the input. I'll try to make some changes so this doesn't happen again.