Fwd: Re: capo-hardening?

[jolly roger]

>Date: Mon, 24 Sep 2001 11:07:44 -0500
>To: caut@ptg.org
>From: jolly roger <baldyam@sk.sympatico.ca>
>Subject: Re: capo-hardening?
>
>>    I have a very vague idea of how sand casting is done, and no idea of
>>what V pro casting is.
>>    Keep the "trivia" coming. Maybe we can get another article from you?
>>    Thanks!
>>    (By the way, I've not heard from Nina this morning)
>>        Ed S.
>
>Hi Ed,
>           V pro  plates.   Vaccum process.  Is a highly automated process
to make piano plates.  The consistentcy of the material is quite different,
and has a whole set of different characteristics than a sand cast grey iron
plate.   It would be more correct to call the V Pro plate an alloy.  Grey
cast is composed of Ferrite (iron) and carbon.  The carbon is suspended in
what as termed free carbon.  The rate of cooling will determine the size
and structure of the free carbon particles.   The very black filings when
dressing the bars is largely caused by these free carbon particles.
>
>The addatives are added to the V pro material to prevent fracture of the
plate, during the rapid cooling process.  Acoustically it may be noted that
companies using the V Pro process, will also sand cast the plates of their
premium models.   Draw you own conclusions.
>
>Roger.
>
>I have been working on an artical on this topic, but it get's quite
complex,  and none of the manufacturers are willing to share what they are
using for a mix.   From the mix it would be easy to look up data ,with
regards to hardness, ductility, and compression strength.
>