Compression ridges was :Do you dry the ribs, along with the board, prior to gluing ?

[Richard Brekne]

I'm not going to get into this whole buisness of whether or not an old 
soundboard can be just as easily and successfully used as a RC&S board 
again.  I'll just quote the main RC&S guru around here from June 2001.  
He's citing an example Andre' posted about earlier that month... a late 
1800's Grotrian that had been re-ribbed.

    While I understand that nothing much I have to say will likely be
    changing anybody's mind on this subject, I'd like to suggest that
    pianos such as Andre's Bechstein (was it?) upright with a re-ribbed
    original soundboard panel would sound about the same had the panel
    been replaced with one of the same thickness and mass characteristic
    made of new wood. It is now the new ribs that are supporting crown
    and forming the stress interface between the
    soundboard assembly and the string plane.

    I suspect the impedance relationship between the soundboard assembly
    and the strings would be about the same in either case.

    Regards,

    Del

Then later in the same month of same year... in response to one of my 
posts in the debate...

        Ric :
        You just posted that a 100 or so year old  panel with new ribs
        "probably" would sound the same as a brand new panel in relation
        to Andre's posting. A direct consequence of this reasoning (and
        the above) is that we dont need new panels at all. Just rip out
        any old panel from an old birdcage wreck...glue it back into one
        piece and rib crown it with new ribs and it will sound good as
        new. I am sure the soundboard manufacturers will be very pleased
        at this notion.


    Del :

    Yes, I did, didn't I? And, yes, all other things being equal, this
    is pretty much the case. After all, just what has changed during the
    life of that old soundboard, be it from an old birdcage wreck or an
    old Steinway grand? Longitudinally, (that is, with the grain) not
    much. There has been some
    nominal compression longitudinally, but not enough to worry about.
    Across-grain, though, we have a problem. There has been a lot fiber
    compression due to compression set and the old wood is now much
    weaker across-grain than it was when it started out. It is also
    considerably less resilient so we can't just dry it out and
    compression-crown the whole thing all over again. We'll have to do
    something about that. The thickness hasn't changed much unless
    somebody got carried away with their sanding. The mass hasn't
    changed much. So, once the original ribs have been removed what we
    have is a panel that is about the same longitudinally, but somewhat
    weaker and less resilient across-grain. Indeed, the panel might well
    have cracked and broken into two or more pieces. We'll solve these
    little problems by gluing the pieces back together and putting on a
    nice new set of crowned ribs. In this way we establish a new crown
    based on the curve cut into our new ribs, we establish some amount
    of cross-grain stiffness (dependent on the length, height and width
    of the new ribs) and remove the necessity to compress the panel
    across-grain to form crown. What we end up with is a rib-crowned
    soundboard assembly that just happens to use the original soundboard
    panel in place of one made using new wood. Makes good use of Earth's
    resources and the acoustics of either will be about the same.


I particularly liked his last statement... in anycase.... since the man 
himself goes good for the basic premise reusing old soundboards in RC&S 
assemblies... I see no reasoning that contradicts what I originally 
stated that started this last flurry.  Nothing wrong with using old wood 
in an RC&S assembly. 

I might add that the debate went on back then... Andre disputed that the 
sound of an old board RC&S and a new board RC&S  would be the same... 
all else being equal as stipulated by Del.  Del responded by agreeing... 
to my surprise... as that post directly contradicted what he wrote 
above....  The road goes ever ever on.

Cheers god people of Pianotech.

RicB