Soundboard recrowning and rib re-arching.

[Ric Brekne]

Thumpy writes:

    Yeah yeah Ok sure. But none of this changes the fact
    that if you stressed the board into an exaggerated
    crown, then permeated the ribs ( and board, maybe )
    with something that rersists compression, you ought to
    end up with better crown when you "knock the chocks
    out".

T

No argument on that point.

    P.S. Still, that rib matter has to go somewhere when
    the board loses crown. Either the rib is compressed
    longitudinally, over the decades, shrinks, or the rim
    expands. Probably a combination of all three. This is
    simpleton stuff.

You might at best experience a little end grain crushing from any 
constraint from the rim.  And we are talking reallllly small amounts. As 
far as being compressed in the face of the soundboard panel itself going 
flat... well I'm open for any data you might have, but the relative 
stress levels the rib and panel can handle would kinda indicate to me 
that you are probably in error.  Not to worry tho... that same argument 
is used to tell me that I am entirely wrong about ribs supporting crown 
in a CC board to begin with. 

Back to your point about rim expanding or rib compressing... you ever 
try that experiment Nossaman sketched a couple years back ... the one 
about checking out the buttressed arch concept ?  I found that rather 
enlightening myself.

Cheers
RicB