circle of sound

[Dave Mckibben]

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I was just at a PTG meeting with Bosendorfer people and they did state what Paul C. said below.
The rim is kerf cut so it can be bent to form to the inner rim, then filled and glued with wedges.  The wedges are sanded and a veneer is laid over the surface.

Dave


----- Original Message ----- 
From: Piano Forte Supply 
To: pianotech@ptg.org
Sent: 1/24/2005 7:04:34 PM 
Subject: RE: circle of sound


The outer rims I saw at the Bösendorfer factory surprised (scared!) me.  

There was the edge grain spruce, as has been described, but it was only about 15 mm (5/8") thick.  On the inside and outside, a sheet of K-3 board was laminated to it!  This is a hard paper press board (think of a peg board).  Then, a sheet of formica is glued on to the outside of that for  pianos that will be black (sometimes called ebony - not to be confused with that exotic, precious wood).  This gives a stable base for the polyester. 

 I understand most companies use the formica trick, but perhaps the K-3 board is the secret ingredient to the Bösendorfer sound ???!

Jurgen Goering
www.pianofortesupply.com



You are both correct.
James has described the inner rim, and Paul has described the outer rim. As
of a few weeks ago, that is still how they are made!

Jerry Cohen, RPT
NJ Chapter

  
It is my understanding that the Bosey rim is not laminated spruce but solid
spruce edge glued and end glued to gether and then the shape is carved out
of that.  That would keep the vibration back to the SB sine there are no
plies to soak it up>
Jim
James Grebe


Bosendorfer released a tech video in the late 1980"s(?), of their
manufacturing plant.  It showed the rim being kerf cut so it would bend
around the inner rim.  The inside and outside of the rim were veneered.
    
The
  
kerf cuts were filled with wedges and the edge(s) veneered to match.  I can
only assume they still do this today.

Paul C
    



  
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