hide glue

[Cliff Lesher]

Paul,

>From "Hide Glue, Learn why this ancient adhesive still belongs in your shop"
by R.S. WIlkinson.  This article was in the April '98 issue of American
Woodworker.

The formulas vary according to the grade of hide glue.  Generally, the
higher the number of the glue grade, the faster the glue will set.
Measurements are BY WEIGHT.

Grade 135 - (I think this is the grade supplied by the piano houses but am
not sure.)  Mix 1-1/4:1, water to glue granules BY WEIGHT for porous wood
(pine); 1-1/2:1 for nonporous woods (maple, birch, etc.)  Benefit:  long
open time.

Grade 251 - Mix 2-1/4:1 porous; 2-1/2:1 non-.  Good general-purpose grade.

Grade 315 - Mix 2-1/2:1 porous;  2-3/4:1 non-.  Very shock resistant.

Grade 379 - Mix 3:1 porous; 3-1/4:1 non-.  Strongest grade.

General notes:

To extend the open time:
 Add 15% urea or table salt by weight.  This recipe will extend the working
time 1  to 5 minutes.

To improve adhesion:
Replace 5% of the water by weight with white vinegar.

For a softer-curing glue:
Add 5% to 15% glycerin.  Softer glue will better accommodate wood movement.

Incidentally Paul, this article was a handout at a chapter meeting not too
long ago.  You may still have it somewhere.

Cliff Lesher, RPT
Lewisburg, PA