Capo hardening

[Doug Richards]

Bill,
I thought the material would become softer because the grain structure
allowed to change in the welding operation (I'm just going from old
memories).  Have you done local hardness testing to find out how much the
hardness in the heat effected zone changed?   Any hardness data you have
would be most welcome.
doug richards
San Jose, CA

> -----Original Message-----
> From:	Bdshull@AOL.COM [SMTP:Bdshull@AOL.COM]
> Sent:	Tuesday, March 02, 1999 7:58 AM
> To:	pianotech@ptg.org
> Subject:	Re: Capo hardening
> 
> In a message dated 99-03-02 09:18:10 EST, you write:
> 
> << Dear list
>  very interesting talk about hardening the Vbar, but how can you do it in
> the
>  real life, I mean, withouth having the plate going to a foundry ?
>  Thank you !
>  
>  Luigi Lamacchia
>  www.inmedia.it/lamacchia >>
> 
> Luigi, the best explanation of procedure is in Matt Grossman's letter to
> Jack
> Krefting, included in the Tech section of the Journal back in '84.  It was
> referenced a couple days ago in a post on this topic.   Briefly:
> 
> The easiest way to reharden the capo today is with the service of a welder
> who
> is skilled in the use of a TIG (tungsten-inert-gas) welder.  If you live
> in a
> large enough community you will find one.  When you discuss what you want
> with
> this person, the level of understanding and willingness to try something
> different should be evident - otherwise find someone else.   All that is
> heated is the outer surface (1mm or so?) of the material.  You want to
> achieve
> a certain contour (others on this list may have more experience with how
> this
> may be achieved) - but at least no broader a slope than exists on the
> current
> bar.   It can be ground slightly for smoothness after reflowing.  You do
> not
> want to change the string height at all, of course.  The plate usually
> must be
> taken to the welder for this service because of the lack of portability of
> the
> TIG welder.  Check out the article - that's how I got started!
> Good luck!
> 
> Bill Shull
> U of Redlands, La Sierra U
> Loma Linda, CA
> 
>