David, I don´t believe that the sounds you described come from hairline cracks. But for soundboard cracks that make bad sounds helps just applying some glue. Usually I do this with old clunkers when the crack is so big that you can see it from the back side of the board. Then I put some white wood glue on my finger and rub it into the crack. That cures the rattling sound, but not anything else like poor crown or so. The idea is not that Samson´s arms grab each side of the crack and drag it together. The idea is rather to prevent the two sides of the crack to touch each other (and thereby making sounds). The same goal would be achieved by any soft material, e.g. felt, leather, silicon or whatever. In the case of a hairline crack you could apply some glue from the upper side. But I would do it only when I were very sure that this is the source of the sounds. What about very liquid CA glue with a hypo oiler? I don´t work with CA, but would it be soft enough when hardened? Gregor ------------------------------------------ piano technician - tuner - dealer Münster, Germany www.weldert.de > Date: Thu, 7 Jan 2010 22:29:50 +0000 > From: David at piano.plus.com > To: pianotech at ptg.org > Subject: Re: [pianotech] Bluthner soundboard problems? > > Since we've been talking a lot about glues lately (PVC-E and so on), > what I want someone to invent for my customer's Bluthner, sigh, is: > > A magic liquid glue which can neatly be fed into a hairline soundboard > crack with a hypo oiler, and whose molecules have arms of Samson, which > will grab each side of the crack, and drag the two sides resolutely > together and hold them there, and the body of the molecules filling any > remaining gaps solidly and with the same acoustical properties as spruce. > > It's not much to ask, is it?? > > Best regards, > > David Boyce. > > In the meantime, I would appreciate advice about what might be done > > with the soundboard? The very narrow splits are not nearly wide > > enough to shim. What, if anything, might be done? > > >I've never seen a split or crack that was "wide enough to shim". You > have to make it wide enough by dragging out wood to provide a narrow > V-shaped groove to press the sliver into, and the best time to do the > work is >when the soundboard has as low moisture content as it will ever > experience. -- like right now in Scotland, for instance. But this work, > from the look of your pictures can't be done properly without removing > the iron frame. > > >JD _________________________________________________________________ http://redirect.gimas.net/?n=M1001xFotos2 Dein Santa Claus hat rote Augen? Jetzt X-Mas-Fotos bearbeiten! -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100108/e4fffa4f/attachment.htm>
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