Chris Schwarz's Blog

Real-life Test: Do You Need Glue?

I build my chairs in a way where glue is only a minor player. And after a stupid mistake yesterday, I now get to test how effective my strategy is.

Before I pull my pants down and tell you how I messed up, here’s the set-up. The stretchers and legs of my chairs are built so they are in tension (I do this by lengthening the tenons in the stretchers slightly). Then, after driving the legs into the seat, I back-wedge the legs’ tenons.

The result is that the undercarriage is a bit difficult to assemble (heavy hammer blows required). But all the pieces pressing against one another also make it difficult to take apart.

Because glue is cheap, I also paint all the tenons and mortises with a coat of liquid hide glue, which is my favorite adhesive.

So yesterday I assembled the two chairs shown above. I went through my pre-assembly ritual checklist and put the first chair together. During the glue-up the glue seemed to be thinner in viscosity than usual, but I chalked that up to the fact that I’d warmed it in some really hot water so it would flow.

After the chair was wedged together, I checked the empty glue bottle. Somehow I had grabbed a bottle that expired in 2016. I didn’t even know I owned an old bottle of glue.

Had my glue gone bad? When hide glue goes bad, it gets runny and usually puts off an ammonia smell. Mine was runny. But there was no smell. And because I had used up the whole bottle, there was no way to make a test joint after the fact.

So now, 24 hours later, here is my plan: I’m going to whack the joints with a mallet and see if they pop open. If they don’t, I’m going to cross my fingers and continue making the chair.

The good news is that even if the joints fail on the chair made with the old glue, I can repair them easily and quickly with fresh hide glue. (The second chair was made with fresh hide glue.)

It’s a real-world experiment. My gut says the chair will be fine. Wish me luck.

— Christopher Schwarz

12 thoughts on “Real-life Test: Do You Need Glue?

  1. C. Stanley Plane

    I’ve been told, Brian Boggs makes his tennons so tight they squeal and pop durring assembly.

  2. TJdaMan

    Do you mean that your stretchers are in compression? Tension seems unlikely but I’m intrigued if so.

  3. yoder

    I did a glue-up test with some old brown hide glue that had been 3 years beyond expiration; the joint actually pulled wood from wood when I broke it apart. Oh, and this glue had rust floating in it because it had completely corroded the nail that was stuck in the nozzle as a plug.

    Not exact science, but it gives us hope.

  4. Edward Clarke

    Hmmm… Hide glue expiration date? I guess that you’re speaking of premixed glue here but just for my information, does the unmixed crystal hide glue have an expiration date? I put the glue that I bought several years ago into a mason jar with a rubber seal and it hasn’t clumped together (yet).

  5. earthartinc

    Chris I wonder if the glue is so thin it just acts like water and swells the joint? Will it shrink down in a few days and more important if the chair is headed to dry country will that be more of an issue. I have several 100 year old chairs here in AZ and every one has shrunk and the joints creak or have required repair.
    An old builder friend always taught me. “It’s never to late to do the job right”. Hard words to live by…. when deadlines rule. Morgan

  6. Just_Iain

    I use the Reminders app that comes with my iPhone to remind me of medications that have hit their expiration date. This is a ‘timely reminder’ to add glue(s) and other ‘shop’ consumables to the list.

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