Soundboard Clamping for Downbearing

[Erwinspiano@aol.com]

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In a message dated 12/20/2002 5:36:27 AM Pacific Standard Time, 
mcpiano@globetrotter.net writes:

> .
> >Marcel wrote:
> >
> >>To me, after the crowning process, the board should not
> >be dried again. I
> >>think that high temperature MIGHT affect the glue
> >hardness and cause crown
> >>collapse (a little at least).
> >
> >Please explain what you mean by "high temperature". And why
> >would it be used?
> >
> >
                         Marcel
                         I often keep the boards in the hotbox after they are 
pressed at what ever temp needed to keep the rh between30 and 40% which is 
often 70 to 80  degrees in a high humidity sesaon. However it doesn't hurt 
any thing if the board is dried down to it's pre-ribbed state of say 90 
degrees and 25 to 30% R.H. Even if you glued the board to the case in that 
dry it will still regain whatever crown was lost due to being redried when it 
gains moisture content.Besides whatever crown there is due to the ribs being 
crowned is more than ample, even in the driest conditions. Purely 
             Compression crowned panels will suffer greater losses of crown 
under the conditons described above and will have very little or none if they 
were'nt carefully dried to about 4.5% EMC before ribbing instead of what 
Peter posted earlier describing basically no drying at all. Peter, what were 
you thinking?
  Next time call 911 -pianotech list.
    Regards --Dale

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