Case separation or delamination question

[David Skolnik]

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Thankyou Boys for your replies.

First, Joe Goss, who wrote:
><0:)

My response?

  (b)..(d)
    ( .Y. )
       V
(Note: It works in Arial anyway.  On the archives it'll probably be a dud)


Terry (Farrell)-
You asked:
>Do you have a chain fall? You can do it pretty easy with that.

No.  Piano is located in a performance space, not a shop (which, in any 
case, I doan' got).  Just curious anyway...how WOULD you do it with a 
chainfall?  With regard to measuring bearing with Lowell gauge...a further 
question.  Do you use it as he outlines in the instructions, in other 
words, spreading the toes (sorry, it's fingers) between the bridge pins to 
read the bridge segment, and then comparing that to the front and back 
segments?

Ron  |    Nossaman wrote:
      =._.=

>Try temporarily clamping the rim back together where the separations are and
>see if it improves the tone.

Ron - No shop, no clamps, at least, not sufficient number to run around the 
entire perimeter.
He also said:
>Ok, new soundboard, made by X. What was the crowning method, and the amount of
>crown originally installed? Being new doesn't necessarily mean it's good. In a
>new board, even with a 60' crown radius, there should be some measurable crown
>through the killer octave. What sort of bearing angles do you find from octave
>4 on up? Is there positive bearing on both front and back of the bridge?

Crowning method was compression, I believe.  I didn't see the piano when it 
first came back, nor before it went out for rebuilding, as this preceded my 
period of employment at the University.  Piano was rebuilt during the 
summer time and, as previously stated, the humidity in this venue does 
hover in the 20% and below region for some part of the winter, at least it 
did so before GWSR  (Global Warming Seasonal Recalibration).    I installed 
a series of crown indicator strings between ribs 3&4, 5&6, 7&8, 9&10, and 
11&12 (piano has total of 13 ribs).  They are held in place with masking 
tape, and I retension them and note bearing whenever I tune.  Most 
recently, the numbers I got were: 3&4 - 1/16"; 5&6 - 1/16"; 7&8 - 1/16" or 
Flat; 9&10 - Flat; 11&12 - Flat.  With regard to bearing angles, I am 
currently revising the method I use for measuring downbearing, and so I 
don't have precise numbers at the moment, however, I am virtually positive 
that the bearing isn't. Why, is that a problem???!!   As far as positive on 
both sides of the bridge...only in my dreams...No, not those, the other 
ones.  What do you consider to be "some measurable crown"? 1/32"? 1/16"? What?

Del - Thanks for your thorough response to the many questions I posed.  You 
asked: (3/30/02)

>This delamination you describe--are you seeing it from the top or the
>bottom.

Bottom, I believe.

>Have the tonal deficiencies been apparent from the start? Or have they
>developed over time, i.e., did the piano sound acceptable immediately
>following the rebuilding and then deteriorate? Or was the tone unacceptable
>immediately following the work?

I'd say it was weak from the beginning.  One complicating factor is that I 
requested that they not do too much hammer juicing to start out, rather 
trying to play piano in.  It came up somewhat, but not to where I suspect 
that the answer to this pianos problems lie in tone building.

>You are probably right, the rim delamination probably did not happen in just
>a few months. But changing weather conditions might cause it to appear and
>disappear. Did you have any reason to look for gaps before the piano went to
>the rebuilder? Is it possible that the gap could have been closed while at
>the rebuilders shop and then open up when it returned to your environment?
>This does seem like quite a gap, but still....

I never saw the piano prior to rebuilding, but, given the extent, opening 
and closing does not seem likely,

>I doubt the loss of crown is attributable to the rim delamination but would
>not want to go too far out on the proverbial limb without being able to
>personally examine the instrument. Rims don't have much to do with either
>forming or maintaining crown. There is a lengthy explanation and you'll find
>it in my articles dealing with soundboards in the Journal.

I thought that even a small shift in the rim could translate into board 
collapse, but I'll read the article first.

>I would certainly address the rim separation problem for the reasons I've
>mentioned above as well as to prevent the cosmetic changes that will occur
>when the outer rim falls off the piano.

I have nothing to say about this last comment, but included it because the 
image speaks to me.

Again, thanks all


David Skolnik

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