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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT =
face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> =
pianotech-bounces@ptg.org
[mailto:pianotech-bounces@ptg.org]<B>On Behalf Of =
</B>Terry<BR><B>Sent:</B>
January 24, 2005 4:03 AM<BR><B>To:</B> Pianotech<BR><B>Subject:</B> =
Re:
Crowning methods, was soundboards.<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>> | ....The other<BR>> | end of =
the
spectrum would be no panel drying at all, and ribs cut/formed =
to<BR>> | the
desired radius. I am not aware of anyone that is at that end of =
the<BR>> |
spectrum.<BR>> <BR>> Walter.<BR></FONT></DIV>
<DIV><FONT size=2></FONT><FONT face=Arial>Really? They rib with =
the panel
equilibrated with room RH - somewhere in the 9 or 10% moisture content =
range?
And then they sell a piano in Minneapolis? Any idea how those boards =
look
after a few years and a couple hundred cycles of high to low =
environment RH?
Any increased tendency to crack?</FONT></DIV></BLOCKQUOTE>
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<DIV dir=ltr><SPAN class=750365117-24012005><FONT face="Comic Sans =
MS"
color=#000080>I misunderstood your comment. Walter is supposed to rib =
their
boards with the panel at 6.5% MC, +/- 0.5%. Not particularly low being =
just
under the minimum MC recommended by most glue and adhesive
manufacturers.</FONT></SPAN></DIV>
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<DIV><FONT face=Arial size=2><SPAN =
class=750365117-24012005> </SPAN>>
| I believe most soundboard manufacturers build hybrid soundboards - =
that
is<BR>> | the ribs will have some radius cut/formed into them =
(often the
60-foot<BR>> | radius one hears of so often) and the panel will =
receive a
fair bit of<BR>> | drying prior to ribbing. Steinway even modifies =
the 100%
compression<BR>> | crowning process by drying the panel, using flat =
ribs,
but gluing them to<BR>> | the panel in radiused cauls.<BR>> =
<BR>> The
result of this is still a pure compression-crowned soundboard. (Think
about<BR>> it....)<BR>> <BR>> Del<BR></DIV></FONT>
<DIV><FONT face=Arial size=2><FONT size=3>Absolutely. I =
understand that.
Perhaps I chose my words poorly. I did not mean to suggest that the =
Steinway
grand soundboard was anything but 100% compression-crowned, but rather =
was
pointing out one variation of the 100% compression-crowned method:
ribbing with a flat rib in curved cauls, as opposed to =
ribbing a
flat rib and clamping to a flat =
surface.</FONT></FONT></DIV></BLOCKQUOTE>
<DIV dir=ltr><FONT face=Arial></FONT> </DIV>
<DIV dir=ltr><SPAN class=750365117-24012005><FONT face="Comic Sans =
MS"
color=#000080>Sadly I've had this discussion with several factory =
people who
seem to believe that by pressing flat ribs to a panel at, say, 6% to 7% =
MC, to
curved cauls does not constitute compression-crowning. But it does. The =
results
are exactly the same -- you end up with a pure compression-crowned =
soundboard
assembly. And, hence, my earlier response to you.</FONT></SPAN></DIV>
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<DIV dir=ltr><SPAN class=750365117-24012005><FONT face="Comic Sans =
MS"
color=#000080>Del</FONT></SPAN></DIV>
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