This is a multi-part message in MIME format. ---------------------- multipart/related attachment ------=_NextPart_001_0009_01C2F642.EF0127E0 This is what your soundboard wants to do when exposed to high humidity. = Below is a photo of my mechanical moisture content (MC) meter. The = wooden part is a 4-foot long by 4-inch wide chunk of soundboard panel. = The panel is about 3/8 inch thick and has two ribs on the back (bottom = in this photo) that are about 3/8-inch thick by 3/4-inch wide. The ribs = were glued on when the panel and ribs were flat and at about 4% or 5% = MC. The meter has been in an 85% to 89% RH environment for three days = now. It seems to have nearly stabilized. I did not measure the crown, = but as you can see it is somewhere around 6 to 8 inches. =20 Soundboard panels in pianos exposed to high humidity are trying to do = what you see above. The stiff ribs and string downbearing pressure keep = it from actually developing 8 inches of crown. And instead of being able = to expand and produce this kind of crown, the soundboard simply crushes. = No wonder soundboard panels develop pressure ridges and then cracks when = they dry back down! The scale on the left goes from about 5.5% MC to = about 8.5% MC. The panel should be in the range of 18% MC in this photo. Fun stuff! Terry Farrell ------=_NextPart_001_0009_01C2F642.EF0127E0 An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/c2/b7/39/63/attachment.htm ------=_NextPart_001_0009_01C2F642.EF0127E0-- ---------------------- multipart/related attachment A non-text attachment was scrubbed... Name: not available Type: image/jpeg Size: 41074 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/cc/75/ee/46/attachment.jpe ---------------------- multipart/related attachment--
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