Q: I have an order for a dining room table that is made out of sycamore quarter-sawn to show the grain. How stable is this wood? Will I have any special problems? I have the same questions about some curly and bird's eye maple.
A: With quarter-sawn wood, the shrinkage in width of the pieces is about half of the shrinkage of flat-sawn. So your quarter-sawn table will be much more stable. Sycamore is a wood that has high shrinkage and is an inherently unstable species. Nonetheless, I do not see that you will have any serious problems if manufacturing is done properly.
For curly maple, the curls or bird's eye represents an extreme variation in the grain angle. As wood shrinks differently in the different grain directions, this striking grain pattern in wood will result in some shrinkage in unexpected directions. A flat surface can get small bumps and areas that are no longer as flat as desired. I would make sure that the customer is aware of such natural tendencies in wood and then do the best you can to control the MC during manufacturing.
When discussing stability of any wood, it is moisture changes that cause the wood to move, not temperature. Moisture changes result when the RH changes, so it's key to dry the wood before manufacturing the table, as close to its final MC in use as possible. This will minimize MC changes after you make the table. Second, use a good finish on all surfaces. The finish will slow (not prevent) any moisture changes and will buffer the wood from any short-term extremes of RH.
There is an excellent video about moisture and its control that the Wood Component Manufacturers Assn. has available for sale ($15). See www.woodcomponents.org for details.
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