Soundboard recrowning and rib re-arching.

[gordon stelter]

Hey, Terry, yore a  real smart guy, so I know, that
you know that when a  board is bent, 1 side goes into
compression, the other into tension. If it is then
glued to a panel, and said panel is smashed flatter
over the years, this rib must also go into
compression, somewhat, or no crown would be lost.
    So, why not flex the panel out, add something to
the wood to resist compression, then take out the
props ?  My only concern would be a loss of elasticity
to an increase in crown. CA is really, really hard! I
IMAGINE this would favor higher frequency production,
but that's not so bad, as it's usually the treble in
old pianos that gets flaccid. 

     Thump


--- Farrell <mfarrel2 at tampabay.rr.com> wrote:

> Thump wrote:
> SNIP
> >>> > ribs might be scraped clean of finish. Then,
> ina
> >> > "flexed out" state, painted with super-thin CA
> >> glue,
> >> > whicj should impregnate the wood, making ita 
> lot
> >> > stiffer.
> >> 
> >> Did the ribs loose some stiffness somewhere? How
> >> much did/do they need?
> > 
> > Well, I'm guessing that he cwassuggesting that for
> the
> > board to go flat, the ribs must suffer some
> > longitudinal compression, as well.
> 
> Longitudinal compression? Where? How? What is that?
> 
> What if they were flat when new - as many are?
> 
> > If they were
> > "stretched" into a bow again, then impregnated
> with
> > some C.A. I would think that thios oud aid the
> crown,
> > greatly. I have an old Knabe upright I think I'll
> try
> > this on. I'll get it toa  stable, low RH< measure
> the
> > crown, bow out ribs and impregnate, and measure
> again,
> > all de-strung, and get back to y'all. But it may
> bea
> > while, so if anine wishes to "beat me to it", i
> invite
> > them to try.
> 
> No thanks. I ran out of condoms and I'm kinda shy
> anyway.
> 
> Terry Farrell
> 
> 


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