Following the Goldilocks discussion, Del's description of a failed soundboard brought this to mind... been meaning to chat about it... >Del Wrote: >What happens when a soundboard fails is part of the same question. Assuming the soundboard was working when the piano was built its impedance did once fall within that “just right” range. As it deteriorates over time—the effect of compression-set reducing the stiffness of the soundboard panel—its impedance changes and it drifts out of that “just right” range. I attended a Bill Schull day long seminar a couple of weeks ago on S&S history at Larry Buck's shop..very interesting day. Late in the afternoon, after Bill was done, 2 chaps from Hampshire Piano in western Ma, as a demonstration of a method to retain and reconstitute original soundboard fabri, had brought some sample rebuilt original soundboards. They described their technique. The board is steamed out from above, steam penetrating the soundboard from above and making its way through the wood to the glue at the rim, case veneer protected from the steam. The board is extracted whole, with none of the pulling of spruce grain that often occurs(even with masking tape..geez). The ribs are steamed off whole, again no damage. Board is re-glued as necessary and an occasional small 1/8 or less piece of old spruce glued in mid panel at appropriate places, to make up for what cross grain dimension has been lost to compression (although they say compression set is BS...we'll skip that, little side show) but in any case returning the panel width to its original width. Panel dried as in compression crowning, original ribs glued back on to original panel, at original grain angle in a dished deck (I think). Old wood configured to original width takes on a healthy crown, and healthy to significant downbearing. What I found real interesting about this is, that as a wood guy, with 25 years of hands on wood knowledge, my experience of "old" or rather "aged" wood has always been that the stuff is an amazing substance, in some ways qualitatively different from new old growth. As a matter of fact, in the shop I have 150 yr old hemlock and spruce recycled from local historic restoration projects, which, when I need a dead stable material, this is the material I go to...dodging the nails etc., but the stock is well worth the occasional nail damage. My hunch has been that the old soundboard wood, if it could be reclaimed with enough left to reuse in a panel, could be, if structure was re-built into it again, as in a new ribbed fabrication, could be a viable soundboard structure. The point that I think they have made is that, even with the compression collapses on the original panel, if structure is built once again into the panel, the compression failures of the original wood, do not necessarily remove the panel's ability to create the spring necessary in a belly, as long as the interaction between panel and rib is reinstated. I haven't heard one of their completed bellies, all we had was the suspect thump test there, but there is no doubt that the boards have significant crown, and can maintain that crown under workable downbearng in a compression crowned setup. I think they are earning at least $3 an hour on these babies( on a good day)...anyone want to line up for a franchise<G> Interesting, I think Jim Ialeggio -- Jim Ialeggio jim at grandpianosolutions.com (978) 425-9026 Shirley, MA
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