Shimming - was: Was it something I said?

[Farrell]

Makes sense Del. I fit my shims by adjusting the thickness of them (they are
cut on a small angle as is the slot - trimming the thickness makes them
wider or narrower). Therefore, I start with shims thicker than my board. How
does one get around this using old soundboard stock that is the same
thickness or thinner than the target board? Laminate two thicknesses
together? Are we not then moving toward a shim that is stronger than the
target board?

Terry Farrell
Piano Tuning & Service
Tampa, Florida
mfarrel2@tampabay.rr.com

----- Original Message -----
From: "Delwin D Fandrich" <pianobuilders@olynet.com>
To: <pianotech@ptg.org>
Sent: Sunday, January 07, 2001 11:19 PM
Subject: Re: Was it something I said?


>
> ----- 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
>
>