----- Original Message ----- From: "Phillip Ford" <fordpiano@earthlink.net> To: "Pianotech" <pianotech@ptg.org> Sent: December 18, 2002 10:30 AM Subject: Re: Soundboardcrown > > > Ron N. wrote: > > > > > It would arc anyway because of the ribs, > > regardless of whether or not it > > > was glued to the rim. Are you intending the > > rim to maintain the crown? > > > > Terry Farrell wrote: > > > That's what I was getting at. It sounded to me > > like he was expecting the board to expand, the > > rim to stay put, and thus put the crown in the > > board. > > My understanding was that Peter glued the ribs > > to the panel while all were EMCed at 60% RH. > > The only reason there was a little bit of crown > > in the board before putting into piano was > > because he pressed the flat ribs into a caul > > that bent under the air pressure. So I suppose > > that would indeed put a little compression into > > the board. But then he dried it way down and > > glued it into the rim. I think he is under the > > impression that drying down the ribbed board > > and gluing it into the case is going to produce > > a bunch of crown because the rim will be rigid > > and support that crown. > > This was what I understood as well. Hmmm. Well, if that is the theory -- it won't work. > > > Del wrote: > > > > > What Peter is doing is simply taking the > > compression out of the panel > > > temporarily, letting the assembly flatten > > out, and then gluing it to the > > > rim. As moisture goes back into the panel it > > once again becomes a > > > compression-crowned soundboard assembly. > > If the ribs are what is maintaining the crown and if you believe the rim > contributes nothing to establishing or maintaining crown what is the point of > drying the board back down before gluing it to the rim? > > Phil F I don't know. Del
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