Soundboard question

[Nick Gravagne]

FROM NICK
In partial answer to RicB's question then, pre-compression of the entire
panel, including its surfaces, suggests a significant challenge to practical
methodology. That said, studies suggest improved mechanical properties with
regard to hardness, static bending strength, and shear strength of
compressed wood due to increasing compression set. This begs the question;
in our panels do we require these "advantages"? Some may think so. As to RH
swings, I would be guessing that the densification of spruce would move its
properties closer to hardwood (or eastern and European white simply closer
to Sitka), and that contraction and expansion due to RH would be just that
-- relative. I would not guess any advantage here, but I would need to
research it further.

GENE'S QUESTION 

Do you really think the spurce would become more dense?
Mass/volume should not change. If the volume is reduced by the restrictions 
noted above the mass would follow. The piece would hold less moisture and 
that is the only variable.
Gene 

ANSWER
Anything can be compressed, including gas, liquids, and solids, even light.
You are correct in that compression (densification) in any medium would not
affect mass and volume, any more than it would a piano hammer. Compression
simply reduces the same mass to a smaller size all around. There is no
change to weight or mass. The number of cells that can absorb and desorb
moisture, however, remains the same so that the piece would hold the same
amount of moisture as the uncompressed piece -- again, same as a piano
hammer. The rate of change to attain adjustments in EMC might be relatively
longer for the same material as density increases. Destructive compression,
however, would irreversibly impair a great number of cells from joining in
the humidity swing party, and in this case the piece would hold less
moisture.