compression ridges and hide glue/Ron N.

[Delwin D Fandrich]

----- Original Message ----- 
From: "gordon stelter" <lclgcnp@yahoo.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: September 30, 2003 10:07 AM
Subject: Re: compression ridges and hide glue/Ron N.


>       So it seems to me that a rib impervious to
> longitudinal hygroscopic deformation, combined with an
> utterly waterproof glue line at the rib/board
> interface could significantly reduce compression
> ridges and board failure.
>      Thump

Mind elaborating on this a bit? I fail to see how increasing the rigidity
of the rib-to-soundboard panel glue joint will reduce formation of
compression ridges. By definition the compression-crowned soundboard panel
depends on an extremely rigid (creep-free) adhesive bond. The propensity
toward the development of compression ridges actually increases with an
increase in the rigidity of the adhesive bond. A flexible bond would allow
the assembly to relax, relieving some of the compression within the panel.
Picture a compression-crowned soundboard assembly with the ribs glued on
using Elmer's White Glue and you'll understand what I mean. But then, of
course, you wouldn't really have a functional soundboard.

Del