[pianotech] U1 - stained bass strings

[Rob Mitchell]

Thanks for everyone's replies on this.  I don't think it's a spill because
the problem absolutely stops at the dampers -- the strings below the dampers
look fine.  

Yamaha said they had one other piano with a similar problem (a GB1 I think).
They think it came from a corrosive outgassing from contaminated Chinese
sheetrock. I suppose the hammers and dampers could be soaking this stuff up
(or moisture for that matter).  But I'm still at a loss to explain why only
the top parts of the strings got attacked.  Perhaps because they get handled
more during the stringing process. 

The customer is already raising this as a warranty issue with the dealer and
Yamaha. 

Rob

Mitchell Piano Service
(415) 994-1030
www.mitchellpianoservice.com

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of David Love
Sent: Monday, October 19, 2009 3:08 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] U1 - stained bass strings

Not necessarily, could be contamination of the string in the factory not
necessarily the copper before the string was made.  Likely a spill in the
piano would show up on other parts of the piano: plate, action, hammers,
dampers etc.  At any rate, the point as far as Yamaha is concerned is that I
seriously doubt that this occurred in the customers home due to acid rain an
atmospheric disturbance or global warming.  Most likely some type of
handling issue from the factory and if it qualifies as a warranty item then
the strings should be replaced.  Cleaning won't work.

David Love
www.davidlovepianos.com


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Bruce Browning - The Piano Tuner
Sent: Monday, October 19, 2009 2:54 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] U1 - stained bass strings

Al,
Contamination of copper wire in factory would wrap completely around the
string, not just on one side as viewed. More likely a spill of some sort.
Bruce Browning
The Piano Tuner.


>   I don't think it's from moisture or atmospheric contamination.  It's
> some contaminant that probably occurred in the handling of the strings
> in the factory or during the making of the strings themselves with the
> copper wrap.  I doubt it will effect string wear or breakage (or tone).
> However, putting alcohol on there certainly can.  If it really bothers
> the owner call the dealer and tell them, maybe it's a warranty item.
> Other than that, leave it alone, you can only make it worse.