# Board glue-up; which is better



## V. Kelly Bellis (Jun 19, 2020)

Does it make any difference which direction the end grain (growth rings) is oriented when gluing up boards?

I recently hand-planed some Home Depot 2 x 6's and glued them together (with splines) to make a wooden base for my bandsaw. After the glue dried I surface planed both faces flat, still using the hand plane. The assembled 22" x 28" pine panel base has been sitting on my on my bench for the past several days, during which I have observed it going from flat to cupped and back down again. I had glued the boards together with each board's end grain orientation the same, shown here labeled as A. But after watching the curling/ cupping and back down again, I wonder if I should have gone with B? Leaving the cup side up for a while, the cupping eventually relaxed back to the panel being flat!

Reactions: Sincere 1


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## Sprung (Jun 19, 2020)

When you brought your 2x6's home from Home Depot, did you let them dry before you worked with them? Construction lumber that you buy isn't truly dry - at least as we think of dry for woodworking uses. If possible, I always stack (with stickers) the construction lumber I buy for at lesat 2 or 3 weeks before using it so it can shed some of that excess moisture. I still can't find my moisture meter after moving, but where we previously lived, EMC was down in the 5 to 6% range and construction lumber I bought would often measure anywhere from 13 to 17% - a huge difference and far from truly dry.

With the panel sitting flat on your bench, one side was exposed to air and was able to dry, the other couldn't - hence the cupping. As the other side then got a chance to dry out, it evened back out.

One thing I try to do when I'm building something - even if I'm using fully dried wood - is to stack all the parts with stickers between the various steps so that there is airflow all around the piece, so that it can shed (or pick up) any moisture equally, yielding less movement of the piece (such as the cupping you experienced).

Factoring in moisture and wood movement - and making sure that I don't have a large surface like that flat up against another surface - the grain orientation while gluing up hasn't mattered so much. But the wood does need to be dry first and you need to make sure that the whole piece has room to "breathe."

Reactions: Thank You! 1 | Agree 2 | Great Post 1 | Useful 2


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## FranklinWorkshops (Jun 19, 2020)

Left to its own tendencies, wood will always cup toward the outside of the tree. The bottom of the cup would be toward the pith. With that in mind, I always orient the wood as shown in your diagram B and I also use an odd number of boards so that the two end pieces will be oriented the same way. This method has worked for me. But @Sprung is exactly right about construction quality wood and assuring uniform air flow to avoid uneven moisture gain and loss.

Reactions: Thank You! 1 | Useful 3


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## V. Kelly Bellis (Jun 19, 2020)

Thank you for your responses gents!

Reactions: Like 1


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## Tony (Jun 19, 2020)

What Larry said!

Reactions: Like 1


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## pvwoodcrafts (Jun 20, 2020)

definitely - B

Reactions: Thank You! 1 | Useful 1


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