what is this corrosion?

[PAT A RALPH]

Carol, I'm sure other techs will confirm, but if you every get into a piano
that has been exposed like this one, the stock response is either total
rebuild or replace AND only rebuild after the piano has set for a year or
two to see if the case is going to hold together.

Ken Gerler

----- Original Message -----
From: Carol R. Beigel <crbrpt@bellatlantic.net>
To: <pianotech@ptg.org>
Sent: Thursday, May 25, 2000 10:15 PM
Subject: what is this corrosion?


> Hope some of you might know what is going on with this piano.  It is about
a
> 14 yr old Kawai GS-30 and four years ago, the household sprinkler system
> went off overhead while the owner was at work.  The piano was completely
> closed (lid and fallboard down) and water was sprayed on the high polish
> finish of this piano for an undetermined amount of time.  The immediate
> observation was that water had not directly poured into the action or
> pinblock area, but the action was damp and the keys were stuck.
>
> The first piano tech on the scene pronounced it a write-off.  Actually, I
> would too using my formula water + wood +  piano + plus insurance premiums
=
> insurance company replaces the piano.  However, for some reason, a second
> technician was called out about a week or so later.  The piano had dried
out
> a bit by then, and he didn't feel that there was sufficient damage to the
> instrument to rate an ethical pronouncement of piano replacement.  The
piano
> owner
> had bought the instrument used.
>
> Anyway, a decision was made to replace the strings and tuning pins that
had
> rusted from this accident - perhaps a dozen.  The insurance company
settled
> the claim  and covered all the repairs that Tech 2 thought necessary.
> By the end of the repair work, several months later, no rust was apparent.
>
> Now, four years later, corrosion is rampant, but in an odd way.  The new
> strings and pins are fine. The speaking lengths of all the strings are
fine.
> Only on some sections where the strings cross  the understring felt is
> there rust.  All the coils are rusted, but it almost looks to me like the
> plating on the old tuning pins is rusting, not the coils themselves. There
> is also rust on the INSIDE of the brass agraffe holes and at the bases of
> the agraffes.
>
> My guess is that the rust is appearing on the metal underneath the various
> platings where the plating has worn off - like the edges of the tuning
pins
> that contact the tuning hammer tip; where string coils friction may have
> scratched the plating on the tuning pins, and on the agraffes where the
> strings passing thru the holes have worn the brass plating thin.  Perhaps
> the rust appearing at the base of the agraffes is where the threads
> underneath the agraffes are not solid brass, but plated steel.
>
> Would a reasonable repair be to clean off the rust, and spray lacquer on
the
> tuning pins and coils and agraffes?  Would that hurt anything?
>
> Could there have been something corrosive that eats plating sitting in the
> sprinkler pipes?  I think residential fire sprinkler systems use PVC pipe,
> not galvanized steel ones.
>
> The insurance company says they settled the claim years ago and they are
not
> interested in funding anymore repairs.  I have been asked to give a second
> opinion in this case, but I have never seen anything like it.  How about
you
> guys?
>
> Carol Beigel
>
>
>