Klarinet Archive - Posting 000416.txt from 1999/04

From: Roger Shilcock <roger.shilcock@-----.uk>
Subj: Re: [kl] Re: Plastics/Wood/Composites
Date: Wed, 7 Apr 1999 21:01:41 -0400

The problem with using words such as "composite" is that they come to have
technical or quasi-technical meanings which differ from their everyday
meanings. For instance, wood is a composite material in that it includes a
number of chemical compounds which form their own substructures, with the
consequence that wood is non-homogeneous, and, as we all know, has
different properties when measured in different directions.
However, clearly it is not a "composite". (I think the same sort of
problem
happens with terms used both in and out of educational contexts).
Presumably, the GreenLine material is supposed to be isotropic, and so
differs sharply from wood in this respect, which may be important. As far
as I know - which isn't very far - just about all synthetic "plastics"
include filler materials to stiffen them and, no doubt, for cosmetic
reasons. I don't know whether the greenLine material includes an
*exceptional* proportion of wood fibre - maybe it doesn't, and it would be
interesting to know.
Roger Shilcock

On Wed, 7 Apr
1999 Spiegelthal.Dave@-----.COM wrote:

> Date: Wed, 7 Apr 1999 10:08:50 -0400
> From: Spiegelthal.Dave@-----.COM
> Reply-To: klarinet@-----.org
> To: klarinet@-----.org
> Subject: [kl] Re: Plastics/Wood/Composites
>
> Dee Hays wrote, in part:
> <There is no published data that shows that this version of
> composite is more crack resistant than the standard ones used in the various
> models of beginner instruments.>
> I'm also a mechanical engineer, not a materials scientist per se, but have
> done much material selection and some testing in the past, and I'd like to
> clarify something (or perhaps further obfuscate it??) A "composite" material is
> one which has fibers or particles of one material embedded/bonded into a resin
> (solidified liquid) of another material. Examples include fiberglass,
> graphite/epoxy composites, particle board, and Buffet Greenline clarinets.
> However, most student clarinets (that I'm aware of) are NOT "composites", they
> are merely molded plastic --- that is, they are all "resin" with no "filler".
> As far as I know, there are no embedded fibers or particles in these instrument,
> so they should not be classified as"composites" like the Greenlines. Please
> correct me if I'm wrong.
> Dave Spiegelthal
> Calverton, VA
>
>
>
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