Was it something I said?

[Delwin D Fandrich]

----- Original Message -----
From: "John Musselwhite" <john@musselwhite.com>
To: <pianotech@ptg.org>
Sent: January 05, 2001 9:39 AM
Subject: Re: Was it something I said?


> At 08:06 AM 1/5/2001 -0500, Terry wrote:
>
> >If you see boards cracking again right next to the shim, my guess is that
> >either it was not glued in properly, board was not dried properly, or
board
> >was not glued back to the ribs at the crack properly. Also, I can get
real
>
> Or... a brand new shim made from fresh improperly dried wood  was used.
>
> Cut shims from old boards instead. They're already dry.
>
>                  John
-------------------------------------------------

The problem is not that the new shim is not dry -- it can easily be made
just as dry as any part of the original board. The problem is that it has
not yet had its cell structure damaged in the same way as the original. That
is, the wood fiber has not yet been crushed by long-term exposure to the
internal compression that caused the crack in the first place. Putting a
piece of new and much tougher wood into the crack puts a new strain on the
wood cells of the original wood that are immediately adjacent to the new
wood. They frequently can't take the strain and fresh cracks develop. Almost
always in the original wood and immediately adjacent to the glue joint.

Making shims out of old soundboard wood alleviates this problem.

Del