[pianotech] re-fabricating a failed soundboard

Encore Pianos encorepianos at metrocast.net
Mon May 28 08:30:28 MDT 2012


The historical conservation aspect of this IS interesting, and should be
considered separately from the kinds of points that Ron is making, because
you are serving different goals with each.  Indeed, I was wondering how the
Anne Ackers of the historical preservation piano world would look upon these
kinds of techniques - are they too activist, or would this be a way to make
these boards respond more like they did when they were new 140 years ago and
give us a closer sense of what they were like originally?  Anyone who has an
active interest in piano design must have a corresponding interest in the
history of piano design  - indeed, so much of what we see today are
recombinant technologies mixed in with some new ways of thinking about piano
design.  What criteria were they trying to serve back then, and how
successful were these instruments at achieving that?   

It is interesting to me to see just how much you could get back from these
boards, given the high standards of workmanship and detail these guys work
to.  I have no particular interest in doing that kind of work myself, but I
would love to hear how successful it can be in achieving a good tonal
result, just to have a better understanding of  what is possible.  I don't
pretend to know everything under the sun, and try to keep an open mind.
The boards they had rebuilt were pretty busted up, and I am not married to
the idea that they were made of magic tone wood seasoned a thousand years.
Even if I had the opportunity to hear one of their completed pianos and were
impressed, I still would put a new board in these beasts, unless they could
reasonably be considered antiques, in which case I would leave them alone.
But that would be my choice, not theirs, and I won't criticize them for
making a different choice than mine.

I think these guys could teach me and a lot of people a lot about steaming
boards out and apart, and I would love the opportunity to steal their
secrets.  I'm hoping we will get them up to New Hampshire to do a technical
in the next few months   


Will Truitt


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of jim at grandpianosolutions.com
Sent: Monday, May 28, 2012 9:39 AM
To: pianotech
Subject: [pianotech] re-fabricating a failed soundboard

>That's been acknowledged a lot of times here. The part of the question
that's left out is what type of construction is being used. Countless
compression crowned boards failed since being built. If these boards being
discussed required re-ribbing and insertion of strips of old spruce to
compensate for the compression set that didn't happen  and take them back to
full width from which they mysteriously presumably shrunk somehow, they were
apparently among the failed. Reproducing the conditions under which the
original failed with the original material seems to me to be rather
optimistic and not really paying attention.


Right. But it should be noted here that the technique was demonstrated in
the context of a conservation of historic fabric seminar.

My interest here was not in suggesting that this technique as a way to make
or replace boards. I don't even buy into the notion that these reconstituted
boards are precisely the board and sound these historic pianos had when
new...actually, as someone coming out of the historic conservation world, I
find that despite whatever conservation method was used, that the result is
still wildly speculative. I'm not interested in basing my designs on
speculative information. My take is that we really will never know what the
original pianos sounded like, except in very broad strokes, like sustain
time.

Rather, my interest was in the panel itself as as a substance. I was curious
to see what resilience was left in a panel which had experienced compression
failure. Not the board as a structure, as we know that's failed, but the
panel wood in and of itself.  Is there any resilience left?  It does seem
that there is, as when the old ribs are steamed off, the panel, though shy
of the original width, still was being restrained by the ribs. They reported
that the wood, freed of the rib restraint, expands somewhat.

However, when they steamed the sucker to get the ribs off, the EMC changed,
so at what EMC was the expansion measured...don't know...

But on the other hand the panel was capable of opposing the reglued ribs, so
there is cellular viability left in the aged compressed wood.

In any case, just take the panel. How would the aged wood with cellular
damage at least at the edges, sound like, if used as a panel substance 
in a new ribbed/designed structure.   My hunch is that the panel, having 
a different resilience profile than when new, would be stiffer than new,
though still resilient.  Carbon fibre, laminated boards, etc are alternative
panel substances which work as panel substances. I wonder how aged
compression beat up spruce, as an alternative panel substance would
perform?  Again, panel as a substance only, not part of the original
compression crowned structure.

Jim Ialeggio





--
Jim Ialeggio
jim at grandpianosolutions.com
(978) 425-9026
Shirley, MA





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