Hot Hide Glue Problem

[David Love]

Yes, I'm not at all claiming you can heat it and make an adjustment.  But
you can heat it and break the joint easily in the case of removing a hammer
head.  

David Love
davidlovepianos at comcast.net 
www.davidlovepianos.com

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Ron Nossaman
Sent: Friday, October 26, 2007 4:41 PM
To: Pianotech List
Subject: Re: Hot Hide Glue Problem


> I can assure you that I've been removing them that way for about 30 
> years without introducing any moisture.  Ungar Heat Gun or smaller 
> Weller Gun, heat the joint, pop them off with a pair of removing 
> pliers.  I can usually heat up an entire section at time and go through 
> and remove them, i.e., it's not necessary to do them one at a time.  
> Interestingly, as the joint cools it becomes more difficult suggesting 
> the glue does indeed respond to heat alone.  There is humidity in the 
> air, of course.  Whether the hygroscopic properties of the glue itself 
> cause it to absorb some moisture from the air which is activated by the 
> heat, I don't know.  Even if that's the case, rarely do we work in zero 
> humidity situations.  But, to be sure, they can be removed with the 
> application of dry heat.  No illusion here.  Try it.        
> 
> David Love

I suspected that's what you were talking about. This is a far 
cry from the original premise that you can heat dry hide glue 
and adjust the hammers without breaking the joint. I've done 
what you're describing too, and my take is that the dry heat 
makes the glue more brittle, and the joint more easily broken 
with shock or pressure. It's a different thing.
Ron N