>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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