Soundboard installation with hide glue

[Erwinspiano at aol.com]

Hi Stephane
  Well the board is a bit warm as it comes out of the box & I  also warm the 
bottle in my glue pot so it is warm & more viscous.  I  apply glue to both 
board & rim.  Usually 2 of us & three if it's a  large piano. However the working 
time is such that I  could do both surfaces by myself
  Dale,  in case I go for cold hide glue (reversible and very hard, if I got 
that right),  what procedure do you recommend ?  Must the wood be warm too ?  
Should  I warm the glue too ?  Is the room temperature critical too ?  It  
seems that I can get the Titebond liquid hide glue here.  On their site  they say 
no need to warm anything, but the articles of Nick Gravagne recommend  to do 
so.

I’m  a bit concerned with the board warming : I put it in a small room at  
35°Celsius and reach 20 % relative humidity.  After one day and one  night, the 
board is completely flat, and the “dead” corner (beyond the dumb  bar) begins 
to show reverse crown. 
Stephane ....my friend...This is roughly 3.6 ish  E.M.C   This is extremely 
dry & cell damage will occur  quickly in a humid climate.  Ask me how I know?
  What is your e.m.c. at the time the ribs are  pressed.  Are the ribs 
crowned.  All this is relevant to your  questions. It sounds like the board was 
compression  crowned
  It's Probably too dry if its' reverse  crowning.  You need a  simple temp. 
& humidity gauge inside  your box to track where the board is at with it's 
E.M.C. content (  equilibrium moisture  Content).  
  In conjunction with a simple chart  that correlates the temp/humidity to 
the emc gives you a close idea where the  moisture content is at any time. 
Really  important!!!!!!!

Does this sound normal ?  Is there no risk to  overdo the board warming ? 
  Yes Of course
  
 I initially intended to leave it dry for 3 days, and I can reach  17% 
relative humidity if I want, but I’m a bit afraid to do more wrong than  good. 
 17 percent even at reasonable temperatures is way too  dry. ie. 70 Degrees & 
25% humidity for spruce  is  roughly  5.4 percent & plenty dry for a rib 
crowned  board.
  35 degrees celcius at 17 percent  humidity is 3.6 percent.
  Ahh this the intense learning  curve we all engage in when we do this work.
  The smart thing you do is to ask  questions.  Next time ask sooner. We 
could be of more  use.

Thanks again for taking time for new board  newbies.
  Hope it all works out
 Dale

Best regards. 
Stéphane Collin. 






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