Soundboard installation with hide glue

[Farrell]

I think Dale is still counting sheep, so I'll throw my 2 cents in. I have also used cold hide glue (the other glue I use is Titebond Extend) with very good results.



Dale, in case I go for cold hide glue (reversible and very hard, if I got that right), 



Very had and reversible, just like hot hide glue. About the only difference between the two is that cold hide glue has a much longer working time - not good for felt work if you don't want the glue soaking into the felt - but great for soundboard work.



what procedure do you recommend ?  



It's real tricky to work with - follow this procedure carefully:  Apply glue, clamp.



Must the wood be warm too ?  Should I warm the glue too ?  Is the room temperature critical too ?  



No, no and no.



It seems that I can get the Titebond liquid hide glue here.  On their site they say no need to warm anything, 



That is exactly what I have done with complete success.



but the articles of Nick Gravagne recommend to do so.

 

I'm not familiar with his article. I really don't know why one would want to heat it. Nick is a pretty smart guy and perhaps he has found some advantage. I would think it would make it set up a bit faster warm - not sure though.



I'm a bit concerned with the board warming : I put it in a small room at 35°Celsius and reach 20 % relative humidity.  



WOW! Those hot box conditions will take your wood down to about 4.25% moisture content (MC). That's pretty darn dry. I presume the panel is ribbed? Can I assume this is a purely compression crowned board?



After one day and one night, the board is completely flat, and the "dead" corner (beyond the dumb bar) begins to show reverse crown.  Does this sound normal ?  



If the board crown is reversing, I should think that you have achieved a MC lower than that when the panel was ribbed.



Is there no risk to overdo the board warming ?  



Oh, I suppose you could. I guess you could crack it at some point, just like you can when in the piano. Probably have to dry it pretty darn low to do that though. If you're going to be drying the board prior to installation and don't know what the MC was when the panel was ribbed, I'd just dry it down to the point where the board is fairly flat - that should be very close to the MC at which the board was ribbed.



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.



See above. Tell us more about the design and construction of this soundboard. Did you build it? Who built it? MC at ribbing? Radius on ribs? Radius on clamping cauls? Etc., etc.



Hope some of this helps.



Terry Farrell

Farrell Piano

  ----- Original Message ----- 
  From: Stéphane Collin 
  To: 'Pianotech List' 
  Sent: Wednesday, January 16, 2008 10:48 AM
  Subject: RE: Soundboard installation with hide glue


  Thanks to all for comments so far.

   

  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.  Does this sound normal ?  Is there no risk to overdo the board warming ?  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.

   

  Thanks again for taking time for new board newbies.

   

  Best regards.

   

  Stéphane Collin.

   

   
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