The finite life of wood grain

[David Love]

I certainly couldn't testify to the notion that there are many undead
soundboards around, at least not that are 100 years old and certainly not
that rely on 100% compression crowning.  Most would be better suited to use
as siding on your house (something you might consider given your description
below).  Most soundboards of that age (in modern pianos) have some level of
failure.  Therein, perhaps, lies the problem.  It's one of definition.
Often tenor and bass sections of older pianos can be passable (assuming no
massive glue joint failure).  That's not surprising since the acoustic
requirements at that end of the piano will be more forgiving on a board
which has lost its stiffness or crown even though the sound may just be less
bad than in other more demanding parts of the piano.  Specifically, the
treble section, where the acoustic requirements are such that stiffness is
required to capture the high frequency vibrations of that part of the scale,
is more prone to failure and it is more evident when it does fail especially
in comparison to the rest of the piano.  If you are willing to accept that
success in a soundboard means that only half the piano needs to perform "ok"
while the other half performs poorly then the incidence of soundboard
failure might be over reported.  But if you demand that the board perform
equally well through the scale, then it is likely that the incidence of
soundboard failure is underreported.  

The occasional board that does survive I would ascribe to the peculiar
characteristics of that piece of wood, stable and benign environments over
the life of the piano, lower threshold of compression in the crowning
process, combined with design characteristics that lend themselves to
reducing stresses on the panel.  Unfortunately, that doesn't describe the
experience of most pianos. 

Pre-modern pianos are something different with different levels of stress,
different scales and different tonal expectations. 

David Love
davidlovepianos at comcast.net 
www.davidlovepianos.com

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Richard Brekne
Sent: Tuesday, October 21, 2008 12:49 AM
To: pianotech at ptg.org
Subject: The finite life of wood grain

The whole problem with this <<soundboards die>> thing is first and 
foremost the fact that there are way too many undead old soundboards 
around. This goes for all types of soundboard constructions. 

Wood that is subjected to seasonal climate changes that are sufficiently 
large is going to deteriorate no matter what the application. Wood that 
is in stable enough conditions will last a very long time indeed. We see 
many 100 year old instruments, particularly Steinways that have very 
fine functioning soundboards. Full of life and punch, no so-called 
killer octave, lovely response and lots of projection power.

The compression damage argument when matched up with the basic RC&S 
philosophy gets shot in its foot.  A panel may indeed be very much 
reduced in size cross grain compared to its original size due to 
permanent compression set,  but when you dont rely on compression to 
begin with to build a panel.. then this fact is by definition a plus. 
Nothing about the permanent compression set inhibits the panel from 
being re-used thus.  Only folks willingness to re-process an old 
soundboard does.  I can refer to a discussion on the matter where Delwin 
Fandrich himself says exactly this in an exchange between André, myself, 
and Del about 8 years ago now.

There is also the subject of how well wood is seasoned before taken into 
use. There are many 3-400 year old houses around here. Small houses made 
completely of wood.  Mite damage is really the major problem. But those 
that escaped that and were otherwise taken reasonably good care of are 
in very fine shape. I have on the other hand 20 year old siding on my 
300 year old house that has developed wood rot in several places.  I've 
re-painted every 3 years, done all the stuff you are supposed to do but 
the stuff just cant match siding that was / is on houses that is from 
the turn of the last century.  We see newer wood constructed houses 
(from the 60's onwards) developing serious structural problems all the 
time around here.

Cheers
RicB