By Robert W. Lang
The single-most important factor in the appearance of any woodworking project is the selection of the material. This isn’t what species to use or what color of finish; it is the choice of which board goes where. The wrong grain pattern in the wrong location can make even the most finely crafted piece look like junk.
While appearance is always subjective, there are traditional approaches to grain placement and orientation that are based on how wood behaves over time. In the grand scheme of things, these arrangements also appear harmonious to our eyes.
This is similar to music. You may want to write a non-traditional song, but the best-sounding notes and chords will be those that have evolved and been used for centuries. Good furniture design, regardless of style, calls for arranging the wood in ways that make sense both visually and structurally.
The key to understanding how any individual piece of wood will appear and function stems from where that piece of wood was when it was in the tree. It is rather simple to discover that by examining not the face, but the end of an individual board.
A living tree contains a lot of water, and when it is cut down and made into lumber that water migrates into the atmosphere. As the water leaves, the cells shrink first as the water within the cells disperses. Then the cell walls lose their moisture, and in the process the cells get smaller and change shape.
This is what causes lumber to warp as it dries, and the vast majority of warpage occurs during the initial drying process. Wood will always be in the process of releasing or absorbing moisture in response to changes in the environment.
Properly dried and conditioned wood won’t likely change shape after milling, unless it is subjected to extremes of humidity. The Architectural Woodworking Institute’s “Quality Standards” recommends keeping relative humidity between 25 percent and 55 percent to avoid problems.
This includes the storage of lumber before milling, the conditions of the shop during project fabrication and the environment where the finished piece will be placed. Extreme levels of relative humidity, less than 20 percent or higher than 80 percent, are likely to cause problems. If you work within these guidelines, problems related to wood movement aren’t likely to occur.
Even so, it is essential to understand what direction any piece of wood you use will move, and the consequences of that movement. Tradition is here to help you out, and if you follow tradition the chances of your finished project looking good are greatly increased.
Article: Read “Why Wood Warps,” by Glen D. Huey, from the Summer 2009 issue of Woodworking Magazine.
Magazine: For an in-depth look at “Composing With Wood Grain,” read the Spring 2009 issue of Woodworking Magazine.
From the October 2012 issue #199
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