Klarinet Archive - Posting 000409.txt from 1998/03

From: "Edwin V. Lacy" <el2@-----.edu>
Subj: Re: Scientific American Article
Date: Fri, 6 Mar 1998 14:44:32 -0500

On Fri, 6 Mar 1998, Bill Hausmann wrote:

> I am confused and curious. Does the plastic actually expand and
> contract MORE than wood? And then is it able to WITHSTAND that better
> than wood because of its very plasticity (lower moisture content, etc.),
> or does plastic expand and contract LESS? Engineers and designers are
> invited to respond.

I'm neither an engineer nor a designer. I'm just a struggling woodwind
player. However, while I can't report any conclusive experimental
evidence to prove this, I feel quite certain that the
scientifically-minded ones among us will confirm that the plastic used in
musical instruments has a considerably higher coefficient of thermal
expansion and contraction than does wood, even a wood as dense as
grenadilla.

I have an all-plastic Loree oboe, and it is a great instrument, with
excellent durability and stability. However, it essentially will not work
at temperatures lower than about 62 degrees Fahrenheit. It contracts so
much that the posts are drawn closer together and the rods begin to bind.
If I have to rehearse on a cold day in a room which is not adequately
heated, I have to get there early enough to blow air through the
instrument in order to warm it enough. In long rests under such
conditions, it is a good idea to put the oboe under one's coat, hold it
under the arm, etc.

But, yes, plastic is much better able to withstand such changes of
temperature and dimension. That's one of the primary advantages of
plastic - it doesn't crack under normal circumstances. It doesn't have to
do with moisture content, but with the fact that unlike wood, plastic is
more consistent in texture and density, having no grain along which
cracking is likely to occur.

Ed Lacy
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Dr. Edwin Lacy University of Evansville
Professor of Music 1800 Lincoln Avenue
Evansville, IN 47722
el2@-----.edu (812)479-2754
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