[pianotech] How to mix up a batch of hide-glue (hammer hanging)

Ron Nossaman rnossaman at cox.net
Tue Feb 2 10:22:23 MST 2010


Andrew Anderson wrote:
> I've been searching my mailbox and can't find anything this specific.
> 
> I've heard how great working with hide glue is, so I bought a mini slow 
> cooker and the glue, now what?
> 
> proportions?  what is the urea for? etc.
> 
> Andrew Anderson (hide-glue rook)

Hi Andrew,
First, where'd you get the glue, and what's the gram strength? 
Here's something I posted on the subject 7 months ago.


More about hot hide glue, since this part has never been 
discussed here to my recollection.

Hide glue comes in different gram strengths. In practical 
terms, it's a measure of the ultimate strength and gel rate of 
the glue. Most people start with too high a gram strength and 
shoot themselves in the foot. Those who say they found hot 
hide to be unmanageable usually bought it from Schaff. Theirs 
is 370-399 gram, which I consider to be impossible for general 
use. Pianotek sells a 251 gram weight, which is manageable, 
but still touchy for general work. I prefer 192 gram. It's a 
balancing act between thickness and gel time. For hammers, 
particularly, you want a fairly thick glue that won't 
"string", and will still gel before it runs down into the 
hammer tail cove.  The high gram weights are super critical of 
water content for this use. Thin enough to not string means 
too thin to gel in time to not sag. The 251g has a wide enough 
operating range, and is quite usable for hammer hanging since 
you can get a quick gel and  minimum sag with a mix that's not 
too thick to use. I find it too much for player and felt work 
though. Add enough water to make it usable covering 
pneumatics, and the initial tack isn't good enough to let you 
move on without standing around holding things and waiting for 
the glue to grab. The 192g is good enough for hammer hanging, 
and much better for player and felt work. It can be mixed 
thick enough for hammers, with a gel time that works, without 
stringing glue, and thin enough for player and felt work 
without losing the initial tack that lets you get on with it.

Dries brittle, scrapes easily, softens with heat and moisture. 
That, everyone already knows.

And no, I don't use urea. I bought some to play with, but 
haven't needed to yet.

Mix consistency (water added) determined by trying it and 
adjusting as necessary.
Ron N


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