[CAUT] Humidity Damage

[Fred Sturm]

Addressing this initial question, I think the notion of invisible  
damage may come from experiences with truly extreme humidity, like  
that caused during a fire when water is used for suppression (that is,  
exposure to steam). Glue joints can be weakened in such cases, but the  
effects might not show up immediately.
	In general, five weeks of 80% humidity followed by 2 weeks of 20% is  
normal - not advisable, certainly not ideal, but conditions that  
perhaps the majority of pianos in the midwest experience every year,  
except that the periods of high and low are longer. Does this cause  
damage? Probably, especially in repeated cycles. Is it quantifiable  
for insurance purposes? Probably not, unless you have soundboard  
cracks. I guess I would say it is unlikely that anything "major" will  
show up in the future due to this one time occurrence. (The string  
breakage i the historic instruments was probably from the pitch going  
extremely sharp, far sharper than in pianos with metal plates)

On Jan 2, 2011, at 1:28 PM, Mckeever, James I wrote:

> During the summer, the humidity was 80% for at least five weeks, and  
> this fall it dropped to 20% for at least two weeks.  The damage to  
> historic reproduction instruments is obvious—snapped strings and  
> soundboard cracks.
>
snip
>
> I am in need of statements from technicians concerning the invisible  
> damage that could have happened.  I need to be able to propose a  
> settlement which will take into account future damage.

Regards,
Fred Sturm
fssturm at unm.edu
http://www.cdbaby.com/Artist/FredSturm

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