[pianotech] Pitch change, etc.

[William Truitt]

My guess is that it is not Delignit.  It's been a while since I have seen a
Seiler, so my eye can't be relied on.  But Delignit has the reddish brown
coloration of beech (which it is made of) and is characterized by prominent
dark glue lines between the lamina.  Hence my "butt ugly" characterization
of it.  

 

Most of the European grands with horizontal laminated bridge caps are white
in color and have barely visible glue lines.  Species of wood I do not know.
Even though Ron says the Delignit bridge capping material is 70 % the
densitiy of the pinblock material, I believe that it is still densified,
meaning that the lamina are crushed into a smaller thickness along with high
heat  in the glue up process.  My experience with the material thus far is
that it is stable and less prone to cracking.  I have been using it to make
new bass bridge caps for vertical repairs, where it is mostly unseen.

 

Have you used your 9 mm. pinblock grade Delignit cap for such bridge
repairs, Ron?  If so, what is your experience with it?

 

Will

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Scott Nelson
Sent: Thursday, April 08, 2010 1:09 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] Pitch change, etc.

 


Some time ago I inspected a Seiler grand that had beeen traded in. Overall
it was in good shape, but I noticed what looked like hairline cracks around
the bridge pins. Upon closer inspection, looking down the long bridge from
the lower tenor end (with the lid off), I noticed the cap was horizontally
laminated, possibly Delignit. Admittedly, this is an isolated example, and I
know that other makers, like Schimmel, use some form of horizontal structure
as well.

 

What was interesting was under favorable lighting conditions, you could see
the horizontal lams statring to split apart and lift at many of the bridge
pins, almost as if the pins were leveraging the cap apart where it was weak.
I used to think that the laminated structure would be stronger, but
apparently the material was yielding in this case.

 

Could this be an example of the Delignit bridge capping material you were
referring to? If so, it would seem that your use of veneer or thinner plies
with epoxy saturation would indeed be more structurally sound.

 

Scott Nelson
--- On Wed, 4/7/10, Ron Nossaman <rnossaman at cox.net> wrote:


From: Ron Nossaman <rnossaman at cox.net>
Subject: Re: [pianotech] Pitch change, etc.
To: pianotech at ptg.org
Date: Wednesday, April 7, 2010, 8:32 PM

jimialeggio wrote:
> I think it would be useful to try and determine if there is any advantage
of  the various maple epoxy laminations over a delignit cap.
> 
> Do we have any data on this?

Not directly, but Delignit ought to make a first rate cap. The stuff sold by
Delignit for bridge capping is, I think, not hard and dense enough. It's a
little over 70% the density of the pinblock stock, and noticeably less hard.
The only real benefits I see to epoxy/veneer laminations over Delignit
pinblock stock are that it looks less like plywood because of the grain
direction of the laminations, and it's less abrasive to edged tools when you
notch.

If you want to try a pinblock grade Delignit cap, I have 9mm material.
Ron N

 

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