Compression Question

[Ron Nossaman]

>If you take an unribbed panel, and dry it out to the extremes of 4% MC,
>and then constrain its dimensions at that so that it is not allowed to
>expand either outwards, or upwards or in any fashion and bring the MC up
>to 13 % the panel will get pretty severely compressed... yes ?... ok..
>If you allow this to sit over enough time that if in releasing the
>constraints the panel simply retains the dimensions it had under
>constrainment.... then what happens to the size of this panel  if you
>dry it down to 4 % again ?


You've seen the answer to this question in a lot of pianos. It will shrink, 
but not nearly as much as an un-crushed panel would. If the panel didn't 
still shrink after being crushed and damaged by restraint under expansion, 
it wouldn't ever crack.

Ron N