Soundboard drydown for installation

jimialeggio5 at comcast.net jimialeggio5 at comcast.net
Wed Jan 23 17:04:33 MST 2008


>Oh, and a practical question about your being in the CC 
>capital of the universe. When the RH% gets into the low teens, 
>say 15%, the MC of the soundboards will be 3.5%, at or before 
>which point a CC board will be flat or have reverse crowned. 
>Do you have a recognized annual killer octave season or 
>festival there?
>Ron N

Ron...

I'm one of the RC&S folks...Just so I understand this, with the RC&S board in the 3.5% example, what would happen shrinkage wise. 

The length of the ribs is not changing, so the ribs are at design dimension, and supporting the 8mm or so board at design values. 

The board wants to shrink (assuming 6 or 6.5 mc at rib glue-up), but is restrained by the ribs except for some (probably negligible)glue creep. 

In this restrained condition, what happens to the board itself in terms of dimensional shrinkage, not in terms of crown/down-bearing/etc, but simply in terms of when will the board want to crack.  

Jim I


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