[pianotech] Glue for hammers - question

[Ed Sutton]

I am curious what the arguments or evidence may be for the tonal superiority 
of a rock solid hammer to shank joint.

A rattling joint is not good, but what is lost if there is a small degree of 
flexibility in the glue?

The hammer felt itself is definitely flexible by design, and not rock hard.

The hammer is not being driven when it reaches the string, it is moving by 
its own inertia.

It is generally considered desirable that the hammer stay in contact with 
the string a period of time, and not rebound instantly.

Eugene Thorndahl, the former glue chemist at Peter Cooper, suggested to me 
that a small amount of glycerine added to hide glue would give it a little 
more flexibility, and produce a more dependable hammer joint, but he was 
addressing the strength of the joint under stress, not acoustic issues.

Ed Sutton



> Meanwhile, to everyone:
> More and more people are saying that they use Titebond molding and trim 
> for hanging hammers, yet I still hear repeatedly how critical to good tone 
> a hard glue is for hammer hanging. Titebond M&T, folks, isn't a hard glue. 
> It's considerably more flexible after curing than original Titebond. Who's 
> wrong?
>