Hi Jim Good post thanks for sharing. Right. But it should be noted here that the technique was demonstrated in the context of a conservation of historic fabric seminar. Then.... this is a horse of a different color. Honestly there have been times when I have had old boards come in the shop that never bellied up originally and were in pristine drop dead gorgeous.... albeit flat condition with no compression damage in evidence whatsoever. In cases like this I've often thought what a waste.I think it would be curious and instructive to reuse the panel as you've described but... I'd rib crown it a bit and dry it less. I'm more curious about the tonal quality of using the old panel versus a new one. To my mind it doesn't negate the "what did it sound like initially clause" in a true restorative to original restoration as it never had crown & compression to begin with. As Del has said countless times,"its a bout mass and stiffness". How you get that doesn't matter as long as it falls into the Goldilocks impedance range. I'm glad to have coined that phrase, It's been useful. Honestly I don't think it would be difficult to sell to some clients of vintage pianos on this idea and you'd be making more than 3 dollars per hour. Its just different strokes for different folks for differing reason. Viva La difference! The problem is some one will start saying its more better or selling it as a features or something with spin on it and I despise that. Dale Erwin Mason & Hamlin/Steinway/U.S pianos www.Erwinspiano.com 209-577-8397 -----Original Message----- From: jim <jim at grandpianosolutions.com> To: pianotech <pianotech at ptg.org> Sent: Mon, May 28, 2012 6:39 am 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20120528/24a8285d/attachment.htm>
This PTG archive page provided courtesy of Moy Piano Service, LLC