Crowning methods, was soundboards.

[Overs Pianos]

Hello Ron N & all,

>>What RH do you glue the ribs to the soundboard at? I assume 
>>anything lower than ambient RH would induce some compression 
>>crowning (once the piano was exposed to something higher, say, 
>>summer's humidity -- today the RH is frightfully low) -- but I 
>>freely admit that's just a gut reaction, not a calculation.
>>
>>Patrick
>
>
>In the neighborhood of 6%-6.5%. Yes, there will be some compression 
>crowning, but not much, and I expect it to be pretty much 
>non-existent in a few months under string bearing. Seasonal swings 
>will always change compression levels in panels no matter how the 
>soundboard is built. My point is that I'm not counting on the panel 
>to support crown either initially, or in the long run. The ribs are 
>dimensioned to do that. The panel provides stiffness along the grain 
>and rides along with the ribs to move air.
>
>Ron N

Similarly, we dry a solid panel down to 6.5%, and yes Patrick, a very 
small additional crowning results once the panel normalises. When we 
use a laminated panel, it is dried after gluing the layers, then 
allowed to stand and normalise before gluing the ribs.

Ron O.
-- 
OVERS PIANOS - SYDNEY
    Grand Piano Manufacturers
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Web http://overspianos.com.au
mailto:ron@overspianos.com.au
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