Hide glue… is surprisingly hard to find
I’m getting another round of bits and pieces together in order to work on the next clock repair challenge in front of me: a circa-1915 mahogany-veneered Ansonia time/strike mantle clock.
Working on this clock is like two separate projects in one: a wood restoration project for the case, and a mechanical rebuild for the clock mechanism itself. And this duality will be true of the majority of the clocks I work on going forward: I like wood mantle clocks more than I like the “figural” or the “stone” cased clocks. So that means I need to learn some things that would be familiar to an antique furniture restorer.
One of the things I need to learn is how to deal with putting a broken case back together, and how to restore the finish. Since these clocks were made something on the order of a century ago, that means dealing with materials and methods that are different from how things are done today. Two big differences: glues and coatings.
Modern glues involve all sorts of plastics and fancy chemicals. They can bond two pieces of wood together so that the bond is stronger than the wood itself- this is great for something that is intended to last at most one generation. Older glues were mostly organic: gelatin, or hide glue, is the most common- it creates a fairly strong bond, but no where near as strong as a modern glue.
Unfortunately, any wood that lasts more than a couple of decades will shift, shrink, dry excessively, and expand with time: in old clocks, this puts stress on those weak glue joints, and that’s what breaks down. In newer clocks, the wood itself usually breaks: the idea is, at that point you throw the item away and buy a new one. With the old pieces of furniture, including old clock cases, the idea is that you re-glue, and use the piece for another generation or two. The old hide glues facilitate this: with heat and moisture, you can return the glue to its original “soft” state, allowing you to remove it/reseat it. Further, unlike modern glues, hide glue can adhere to hide glue so your cleanup doesn’t have to be perfect. Modern glues, on the other hand, require harsh chemicals to “unbond” or remove, causing damage to surrounding finishes and even the wood itself… and if you fail to thoroughly clean the old glue away, the new adhesive won’t bond very well.