Soundboard stiffness variances

[Erwinspiano at aol.com]

Ok
  Lets' do it.  I challenge you to do this.  Find 2 , 36 inch long sections 
of 1/4 sawn sound board  spruce...approx. 6 inches wide .I.e. as if it were cut 
right out of a  panel.  Dry one of them down to 3.5 % emc & the other to 
about 6% emc.  Glue on a flat rib/bar with typical dimensions of what you might 
find on a sound  board of that cross section. Even scallop out the ends as is  
usual. Now  while dried down, glue on the rib on a flat table top. Now  give it 
three days in 50% plus humidity conditions & then tell me a few  points of 
moisture content don't' make a difference. One will be far more bowed  than the 
other.
 The power of wood cells in compression is enormous &  it will produce much 
stiffness on it's own when its' restrained from expanding  on one side.  enough 
so as to bend a flat pine/spruce rib which is pretty  dang stiff all on it's 
own.
  I think that because the American climate may be so  different from parts 
of Europe, & that sound board making techniques have  adapted to them as well, 
that our semantics & experiences may be  missing each other like ships in the 
night.
  Regards
  Dale
 
 
 
 
Let's test the properties of spruce over the range of dampness to  
which it will be subjected and then see how significant the change  is.

JD


 
 
Dale Erwin--Piano Restorations
4721 Parker  rd
Modesto, Ca. 95357
Shop 209-577-8397
Web site _http://www.Erwinspiano.com_ (http://www.erwinspiano.com/)  
Restoration & Sales of
Steinway &  Sons & other fine pianos.
" Soundboards by  Design"




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