Glue tests

I’ve recently acquired few different hide glues i’m trying out. Other one of them is really fast and strong gelling glue with high clarity. Supposedly it should be actually some fish glue mix, but its hard to believe given its properties.
Other one is this weirdly thin flaked hide glue, very slow gelling, really dark glue. Its not as slow as fish glue, but slow for hide glue.

I made a simple test:

  1. Dark hide glue
  2. Clear hide/fish glue
  3. mix of both
    I clamped them down, attached a scale to the wood pieces and ripped them apart. All pieces took similar strength to have them tear.

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I think that this kind of test is quite ambiguous. Wood to wood joint with almost every animal glue is really strong. Thus, strong enough to tear wood when broken. Instead, wood to horn joint is what we are interested in, and I believe that is is possible to find differencies between different kind of glue and glue types. There should be easy test standard for testing different kind of glues, and especially wood to horn joints. I have tried something but I am not yet happy, results should be measurable.

This is so far the best document about animal glues and their general properties. But it would be great to invent some kind of test method to find the best glue for horn bows.

Animal_glues_a_review_of_their_key_prope (4).pdf (176.3 KB)

Well thats sort of true. I’m also interested in how the glue behaves with sinewbacking. Different glue could be used for sinew backing and horn joinery.
What i learned here, there wasn’t much difference between these 3 glues.

I’ve come to think recently that glue strength might be the least important thing when it comes to horn joining… Surely the glue needs to gel and dry properly, but a lot of people are scared with storing glue solution, never boiling glue, hydrating glue first for long period etc etc.
My experience tells that all the situations my bows have failed from horn joinery, there has been air bubbles or bad adhesion. Which has very little to do with glue quality. It would be nice to have some super strong glue though that you would have some more failure tolerance…
Feel free to do tests! Groove some scrap horn and glue to wood, or just use planed/sanded surfaces.

Ivar also raised idea to make elasticity tests. I don’t know how that would be best arranged. Maybe just have a thin piece of maple, layer with glue and then bend?

Replaced sinew in one limb with this glue. Works just fine. We’ll see when i bend it. Color seems quite dark brown.