Walnut end-grain cutting boards keep cracking
I sell walnut end grain cutting boards on Etsy and have been having some problems making them. The problems have been getting worse since the temperatures have been getting colder. I live in lower michigan and it has been around 25 degrees F lately, and much colder and night. A few days ago, I glue up my walnut pieces, planed it down and then recut it to make it end grain and glued it all back together. The wood had been sitting out in my garage where i do all my work but my wood glue always stays inside. After I glued it, I brought it inside to dry, and the next morning i took off the clamps and everything looked fine. I brought it over to my neighbor’s in the morning where i could drum sand it and left it in his barn (which was probably the same temp as my garage) all day untill I got home and could sand it. When I went to sand it, there was cracks all over the board. There was almost no cracks along the glue joints but rather cracks accross the grain in random directions. So I assumed that maybe I needed to bring the wood inside and let it warm up before i glued it. I recut all the pieces and brought all the wood inside to warm up. I glued everything up just like before. This time when I sanded it, the cutting board stayed in the van all day and when i got home, it was cracked again. This time it cracked along the glue joints in about 10 different spots. I can’t seem to figure out what is causing the cracking since the wood was warm before I glued it. I’m starting to wonder if maybe the wood is cracking when I bring it from the warm temperature inside and bring it instantly out into the cold. I also checked the moisture levels and it is around 9%. If anyone knows why my cutting boards keep cracking or have any ideas about what I should do, that would be great.
Thanks,
Joshua
Replies
Random changes in temperature are bad. Keep everything (glue and wood) the same temp throughout the process. Leave it all inside for a coupla days before and after you glue up.
Ok, thanks for the quick reply. On the second glue up, the glue and wood were the same temp when i glued it up. I can keep the glue up inside for a few days, but i still think that it will crack as soon as i bring it back out into the cold temps because it goes from 70 degrees to 25 degrees??
The glue bottle’s label has a temperature for use (usually around 50*F). I would keep everything above that long before and after the glue up. Best to you and your business.
Yeah, I have kept it all above that temp. I just bring it out into the cold to glue it and bring it right back inside. So i'm trying to figure out why it keeps cracking
9% moisture is a bit high for making wood items, especially in the winter since the indoor air moisture is low. Being end grain makes it worst .
I thought that normally when lumber companies dry wood, they dry it to about 12% so i thought that 9% was low or is this not correct?
7% is usually the target for kiln dried wood. Wood that cracks os losing moisture. The relatively short dimension (thickness) allows the moisture to leave quickly through the end grain. Try cutting to size and allowing to acclimate longer - several days at the low temp/humidity before gluing. Or, you could coat the end grain of the cuts with shellac to really slow down the movement, and allow it to leave via the long grain. That should solve the problem.
This is all the same stock right? Did you check moisture content on the end of the board before cutting it all up?
Yes it is all the same stock and yes i checked the moisture...it was at the highest 9%
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