Soundboard installation, next topic : the glue

[Stéphane Collin]

Hi list.

I am glad to see what nice comments did raise from my naïve lack of
knowledge in soundboard installation issues.  Though, I was following the
process described by Nick Gravagne in the January 1988 journal.  Astonishing
how an idea regarded as common sense (soundboard, even ribbed, changes
dimensions when loading moisture) can appear to be fallacious, when it comes
to practical consequences.  Nothing is that simple.  I learned many crucial
things from you all.  Thanks there for.
The bunch of high quality informative posts that raised from that trivial
point encourages me to let alone the fact that I show my ignorance on the
topic, and feel confident asking you all advice on the next topic that I
face now : the gluing of the soundboard.
In a first time, I was convinced that liquid hide glue (Titebond from
Franklin) was the answer for this job (dries hard, good gap filling
properties, long working time, excellent reversibility).  No doubt that
Terry and Dale, who spoke of this, have excellent results with it.  But will
I ? in my world ?  That is the question.  What makes me doubt is that I
asked a Titebond technician how the glue joint would behave in my climate,
which is 25 % relative humidity in the worse days of the winter and 65 % in
the wettest days of the summer.  Here is what the guy answered me :

" The Titebond Liquid Hide Glue is sensitive to humidity, even when dried.
At the least, it can soften in the humidity you describe. If the substrates
part during that time, the bond will fail. If the substrates remain together
during that time and the humidity lowers, the bond will remain. I hope this
answers the question."

Now, I understand that for a harpsichord or a pianoforte, this is of some
concern : the board exposed to this kind of humidity could move in the
piano.  But I imagine also that in a modern piano, the board is sandwiched
between the hard wood rim and the cast iron plate, at least for more than
half of its perimeter.

I would like to ask Dale and Terry and all, what is the kind of climate your
instruments go to ?  And if indeed the glue joint does soften in heavy
moisture situations, maybe this is not a problem as the board remains in
place due to plate screwing.  What do you think ?

Best regards.

Stéphane Collin.