glues, Poletti

[Richard Brekne]

Hi Anne

Creep in conditions like you mention seem quite easy to understand.  
There is a kind of shear stress on a hitch pin rail that is glued to a 
soundboard. But there is another point from his site I found very 
disturbing . The assertion that Titebond and similar glues never really 
harden and impart (to some degree)  kind of damping effect, absorbing 
some of the vibration energy instead of either reflecting or 
transmitting. This has immediate implications for modern piano building 
as well as older instruments.  I'm not so sure how much a problem Creep 
is in situations where there is not immediate and significant levels of 
shear stress on the glue. But I'd like very much to hear more in depth 
comments about all this in general.

I'm not sure I'd have a problem using Titebond to fix a broken shank out 
on some field repair job.  But thats not really what I was talking 
about. When in a restoration shop one has a variety of choices at hand.

Cheers
RicB


    Ric wrote:

        Hi Folks

        Reading in one of Anne Ackers i found a reference to the website
        of one
        Paul Poletti who has a side dedicated to glue. Please look over the
        following and provide comment.

        Thanks
        RicB
        ******************************



He's absolutely right.   Most harpsichords built with aliphatic glues in 
the 1970's and 1980's demonstrate cold creep very nicely with the 
shrinking of the gap as the soundboard creeps forward, e.g.

Besides, hide glue is so EASY to use.   If it stinks, you're using bad 
stuff.

Anne