Shims and soundboardrepair.

[David ilvedson]

How many who are shimming have used Bill Spurlock's router 
shimming system?  Any comments?  

David I.

From:           	"Brian Trout" <btrout@desupernet.net>
To:             	<pianotech@ptg.org>
Subject:        	Re: Shims and soundboardrepair.
Date sent:      	Tue, 7 Dec 1999 10:23:36 -0500
Send reply to:  	pianotech@ptg.org

> Hi Ron,
> 
> You bring up an interesting question.
> 
> I have taken old sections of soundboard and sawed shims out of them.  The
> reasons I did so may or may not have been good ones.  (I haven't shimmed a
> soundboard since I replaced my first one.  I guess it spoiled me.)
> 
> When we were doing more shimming, we used to dry the board out a bit, (I
> don't think we had a specific RH or MC), put wedges underneath between the
> board and the beams to force it up, and then start shimming.  We would open
> up the cracks on the top side of the board as nicely and evenly as we could
> with a tool that made a nice V-groove the right shape for a shim to go in.
> We almost never had need of a shim that went all the way through the board,
> so the old shims were tall enough for what we were doing.  We would glue
> them in, and then when the glue was dry, take a sharp chisel and smooth them
> out flush with the surface of the board.  What we were doing would probably
> have been considered more of a cosmetic repair.
> 
> The initial attempt at making the shims from old soundboards had nothing to
> do with expense.  We had two problems that we thought we might be able to
> help with.  The first was appearance.  The new shims we were getting were
> very white wood, and stood out on the old boards.  We thought that perhaps
> the old wood might have a little more color.  It did tend to have a little
> more color, but was still whiter than the surrounding board.  The second
> thing that was bugging us was that the new shims did not come to a point on
> the bottom.  They were often too wide to get into smaller cracks that we
> didn't want to open up far enough to get the new shims into.  The shims that
> I cut out were almost as tall as the old soundboard was thick, and most all
> of them had a nice sharp edge on the bottom.
> 
> I don't know if these were good or bad.  I do know that the other techs
> gravitated towards those shims.  It seemed that given the choice, they
> always picked up the ones I had cut out.  I think they are used up by now,
> and I never did make any more.  Like I said, I got spoiled putting in new
> boards.  If I were to start shimming again, which I will probably do at some
> point, I may re-evaluate my methods of shimming, and perhaps the new shims
> might work better with a new method.
> 
> Interesting thoughts though, Ron.  Glad you piped in.
> 
> Brian Trout
> Quarryville, PA
> btrout@desupernet.net
> 
> 
> ----- Original Message -----
> From: Ron Nossaman <nossaman@SOUTHWIND.NET>
> To: <pianotech@ptg.org>
> Sent: Monday, December 06, 1999 11:53 PM
> Subject: Re: Shims and soundboardrepair.
> 
> 
> > Danny,
> > The old wood has also been under compression for a lot of years and has
> > suffered some accumulated compression set. Actually, I doubt that there is
> any
> > harm at all in using old soundboard material from one board to shim old
> > soundboard material in another. I doubt that there is any benefit either,
> but I
> > don't see any harm. The salvageable portions of the old panel will be the
> > planks that haven't failed to the point of cracking, and if the board
> being
> > repaired still has some crown under string bearing load, and the budget
> doesn't
> > allow soundboard replacement, then why not? The shim material will be of
> about
> > the same degree of deterioration as the board being shimmed. Of course,
> the
> > fact that the board being shimmed *is* being shimmed means that it has
> > deteriorated enough to crack in the first place and is at least somewhat
> > suspect. I have a question though that is more practical than judgmental.
> If
> > you have a cracked panel that is quarter sawn, and want your shim to have
> > roughly the same grain orientation as the panel, how are you going to cut
> shims
> > that are both deep enough, and with the proper grain orientation out of an
> old
> > quarter sawn soundboard panel without laminations?
> >
> >
> >
> > Ron N
> >
> 
> 


David Ilvedson, RPT
Pacifica, CA
ilvey@jps.net