Soundboard repair question

[Annie Grieshop]

That's what I had told the guy who asked the question, but I thought I'd
ask, anyway, in case I was missing something.  I hadn't thought of epoxy as
being able to expand and contract, although I know it's used in all sorts of
wood repair/stabilization jobs... so it has to be able to do that.  Doh.

Does epoxy repair change the soundboard response, then, or does it simply
stabilize the board and ribs?  Forgive me if I'm asking questions that I
should already know the answer to, but I don't know.  (I have lots of
hypotheses built around what I've read and observed, but there are some big
cracks in those, I'm sure. <g>)

My thought is that any material other than wood (and a similar wood, at
that) is going to affect soundboard response negatively, but I don't know if
it's as negative as a crack (which looks to me like a barrier to vibration
transmission from one part of the board to the others).  Is any of that in
the ballpark, even?

Thanks.

Annie G.

> -----Original Message-----
> From: David Love [mailto:davidlovepianos at comcast.net]
> Sent: Saturday, February 09, 2008 10:02 PM
> To: annie at allthingspiano.com; 'Pianotech List'
> Subject: RE: Soundboard repair question
>
>
> Won't hold up, won't help.  Whatever material you fill the cracks
> with needs
> to be able to expand and contract like the panel or it just cracks again.
> Also, filling the crack in this manner won't change the
> soundboard response
> anyway.  With respect to cracks, the biggest concern is rib separations.
> Those should be repaired as they can make noise.  Soundboard
> cracks don't on
> both counts.
>
> David Love
> davidlovepianos at comcast.net
> www.davidlovepianos.com
>
> -----Original Message-----
> From: pianotech-bounces at ptg.org
> [mailto:pianotech-bounces at ptg.org] On Behalf
> Of Annie Grieshop
> Sent: Saturday, February 09, 2008 4:51 PM
> To: Pianotech List
> Subject: Soundboard repair question
>
> This question was posed to me yesterday by the facility manager of a local
> community center:  could a cracked soundboard be repaired by dripping CA
> into the crack (as is done with bridges)?
>
> My questions were:  would CA hold up and would it help?
>
> I didn't know the answers to any of those, although I could hypothesize
> some.  BTW, I told him NOT to try it, since both the pianos with cracked
> soundboards are Steinways:  a 1950s B and a 1931 L that's been rebuilt and
> refinished.  And nobody ever mentioned (or remembered) to think about
> humidity control.  Harrumph!  The cracks aren't horrid, but they
> are there.
>
> Thanks for any comments.
>
> Annie G.
>
>