Whole room humidity control better than Dampp Chaser. ( Right?)

[Paul McCloud]

Hi, Terry:
    I live in San Diego, and have sold lots of string covers.  I've seen string covers made of synthetic material where the strings were rusted/corroded, and covers made with wool where there's no rust.  It seems to make a difference.  Wool absorbs moisture, and also gives off some by evaporation.  Even in very damp environments, it doesn't get "dripping wet".  If it did, you'd hear complaints how the covers made things worse for the piano.  It provides a barrier.   I almost always suggest a DC system where there is a lot of humidity (right on the ocean).  The proof is (assuming the DC is kept plugged in) that there's no rust  under the cover.   And no dust/dirt either.
    My experience.
    Paul 

Paul McCloud
Service Technician for PianoSD.com
www.pianoservsd.com 
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----- Original Message ----- 
From: Farrell 
To: Pianotech List
Sent: 02/18/2008 7:19:35 AM 
Subject: Re: Whole room humidity control better than Dampp Chaser. ( Right?)


Andrew - I've heard this before. I'm not going to argue against it, but I have to admit it makes no sense to me. Perhaps I just don't understand. Logic tells me that if the wool cover "buffers" humidity, that means it absorbs humidity. Humidity is water vapor, i.e. water molecules. So where does the water go then? At some point, the blanket is going to start dripping when it reaches saturation.

If one were to ring the wool cover out now and then and discharge the water that way, I could understand, but otherwise it seems impossible to me. What is the physical/chemical mechanism at work here?

Are you aware of any authoritative source of information regarding this?

Thanks.

Terry Farrell
----- Original Message ----- 
A wool-felt string-cover alone will protect the strings against rust.  That has been well established by grand pianos in (ocean front) beach-houses with string-covers that have brand-new looking interiors after decades as compared to their unprotected neighbors.  Wool has the natural capacity to buffer humidity and any sort of cover probably prevents condensation.  This is the first accessory I recommend.

Add a DC system and undercover and you will then reduce the sound-board oscillation to negligible resulting in tunings that last until your next service.  You get to do a concert level tuning each time you return to the instrument.  

I have two Sauters on the floor here.  They are fine pianos which are much more stabile than average.  One has a DC with undercover and the other has DC with undercover and string-cover.  The one without the string-cover is noticeably (to me) affected by the weather.  The other one hasn't been tuned in a coon's age and still has a solid tuning on it.

YMMV
Andrew Anderson
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