[TPIN] Superior/Inferior Brass

[Allegro69]

It's been ages since the last 'debate'. Bill mentioned the process of
heating the horn to return it to a normal state. On the flip side of the
coin, it has been said that subjecting the horn to super cold temps (-320)
will do the same thing, as mentioned on this link to Osmun Music.
http://www.osmun.com/services/re.htm


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Message: 18
Date: Wed, 24 Jan 2007 15:06:01 -0800
From: "William Graham" <weg9 at comcast.net>
Subject: Re: [TPIN] Superior/Inferior Brass

> The metals that make up Brass are generally the same from each
> manufacturer, today and years past.  However, construction processes
> have changed considerably, due to technology.  This raw metal goes
> thru stresses due to hammering, bending, soldering, cutting, shaping
> etc... to produce the instrument.  These stresses redistribute the
> molecular structure in uneven patterns.  As an instrument ages, the
> metal slowly relaxes as the molecules return to a normal state.

I don't think this is true....No matter how old the horn, the molecules
won't, "return to a normal state", because the brass is a solid, and the
molecules are trapped in the crystal structure of the metal. You can,
however heat the horn, (or parts of the horn) and bring the temperature to
the point where the molecules can flow into different positions....They call
this "austempering" (IIRC). It is used in the aircraft industry to relieve
the internal stresses on airplane skins and the like.....I see no reason why
it can't be done on horn parts before they are soldered together......