This is a point that has had me scratching my head for a long time.
Strikes me that a board that is dried to 4 % MC before ribbing will
simply return to this state at any time in the pianos life the MC gets
back to that level. It will simply flatten out... and their will be no
compression stress in the assembly. If string downbearing is
appropriately set to begin with.. there will be no downbearing either.
Whats the problem ?
If on the other hand a board is simply dried to 6.5 % MC... then
ribbed.... regardless of what kind of ribs one uses, if it reaches 4 %
MC at some point in the future then THIS is the board that should worry
about reverse crown... splitting apart... or worse. What am I missing
here ?
Cheers
RicB
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?
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