Author: Wufus
Date: 2012-02-09 15:25
We have to be careful how we apply results from "scientifically conducted studies conducted in controlled environments" In general most of the studies are conducted on slabs of wood, or building material such as two-by-fours or plywood. And it is true that for all intents and purposes thermal expansion is relative negligible for these applications.
An oboe on the other hand is a small tube with a conical bore, a very different geometry and mass, which changes how the science is applied.
The following statements are taken directly from a publication from the Society of Wood Science and Technology which I hope qualifies as a "major player in the lumber industry".
"Expansion parallel to the grain is VERY small compared with other common solid materials..." "[the coefficient] across the grain is greater than all metals and other building materials. In fact, [the coefficient] is up to 10 times what it is along the grain." Across the grain expansion is the bad kind for oboe cracking.
www.swst.org/teach/teach2/properties2.pdf
Here is how this applies to the oboe. Because the wall of the oboe is thin (mass) and the temperature differential across it is great, the expansion/contraction across the grain can happen fairly quickly causing stress which could lead to cracking.
Same science, different application. A very important distinction.
If we apply the assumption that humidity is the predominant factor, then it would follow that oboes played in very dry climates would also be prone to cracking. I am not aware of this being a problem. Also thermal expansion/contraction happens much, much quicker than that caused by moisture.
I am not saying that humidity does not play a role, wood is greatly affected by moisture and the lack thereof. When I said that it was "misleading" to say that temperature has no effect on wood I was concerned that people may not take changes in temperate as seriously which would be a mistake.
I have a degree in Chemical Engineering which includes studies in Physics, Heat Transfer, and Material Science among others.
Sorry for the length. Just wanted to state my case scientifically.
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