The Robustness and Reversibility of Hide Glue

One of the frequently voiced concerns(?)/legends about hide glue is that it should or should not be used because it is so moisture sensitive and joints are prone to failure.  From one perspective this feature makes it an unreliable adhesive, from the other it is a near-perfect glue for working on historic artifacts.

A couple weeks ago I used 192 gram strength hot hide glue to assemble a portion of a 7/8″ stock dovetailed box (I will be blogging about the project as a whole once I am done with it) and for some reason the joint dried with a bit of twist.  Not a ton, but it was aggravating and probably the result of me inattentively setting the workpiece onto an unlevel surface.  So I decided to undo the joint with some water and re-do it correctly (which I did ex poste) this past weekend.

I swabbed the joint inside and out with water and returned a couple hours later.

No effect.

I wrapped it with a wet rag and let that sit over night.

No effect.

Finally I immersed the entire joint in a pan of water and left it to sit and soak.  And soak.  And soak.

It took two days for the joint to come apart.

If that is “water sensitivity” I can only imagine how robust my joints are when I crosslink the hide glue in situ.