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This part of the chair was damaged during shipping and I was wondering if it would be safe to glue together.

enter image description here

The part on the left is a leg and the horizontal bar on the right supports the front of seat. I would imagine that the broken joint supports a bit of weight. Would glue be sufficient to hold it together?

The tenon is stuck firmly inside the mortise, I don't think I can extract it. If I were to attempt to glue it back together would I apply glue on the entire side face of the leg or just the broken tenon?

Here is a side view:

enter image description here

I have very little woodworking experience, so any advice would be greatly appreciated.

Additional pictures:

[enter image description here2 [enter image description here3

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    There would be no way to extract the broken portion of the tenon in the mortise even if you had access to it from the top, unless the glue joint were very poor. A tenon is held in the mortise largely by a long grain/long grain glue joint, the strongest glue joint there is and in practice it's regularly stronger than the wood around it. So an attempt to extract the tenon would almost certainly break the wood somewhere, and still leave the tenon stuck in place. – Graphus May 7 '17 at 10:24
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    Now about your broken chair, I think the best advice here is not to try to fix it yourself if you don't have woodworking experience and a reasonable selection of tools. It is easily fixable in a couple of different ways, but all require some level of woodworking experience to do and a decent selection of tools. The fixes I can think of that don't require either of the above are the usual 'hack job' fixes that you see done by homeowners who try to fix it themselves, and invariably they look awful and don't hold up to use. – Graphus May 7 '17 at 10:26
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    Seems like a dowel or two running directly into the broken part of the tenon + glue/clamps would work just fine. – jbord39 May 7 '17 at 15:57
  • If it was broken in shipping, can you send it back? – PProteus May 15 '17 at 16:43
  • Shipping it back wasn't an option unfortunately. – KZ. May 19 '17 at 17:39
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I lack confidence that the glue joint would hold. The loading on the chair was great enough that it separated the grain in the wood. Part of the reason for the failure was that the seat support rail did not have straight grain carrying the load across the entire width of the chair rail. Instead the grain angled to the outside leaving little of the length to support the loads. While it is argued that the glue joint would be stronger than the original wood, the strength is still limited by the small area wood grain to support the stress.

I would be inclined to replace the piece by drilling out the remaining rail segment in the leg tenon and making a new chair rail with a better piece of wood. This will take a bit of woodworking experience to do so you may want to find an experienced woodworker to repair the chair for you.

  • The chair itself is pretty cheap - about $150/ea, so hiring a wood worker is probably not cost effective. I do agree that it would be the better fix if it was within my skilset. Thanks for the suggestion. – KZ. May 7 '17 at 23:18
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I agree with Ashlar's answer and I was going to say many of the same things, so I will just add some alternatives. My answer will depend on exactly what the break looks and how easy you think it will be to work with but if you want to try a little DIY here are some suggestions

  1. The easiest option would be to glue it and then drive a screw through the joint, but that would probably not look very nice.

  2. An alternative to the screw is to run a dowel though the leg and into the support. To do this you should glue the leg together and once the glue sets up drill a hole into the support then glue in the dowel and then cut the dowel flush. This image shows the theory I am describing but in your case you would want to run the dowel in from the other direction as your tenon is already stuck in the mortise. Animation from technologystudent.com

enter image description here

  1. If you are really worried about the outer face then you could try to embed the dowel inside the joint, this would be harder and require you to be very careful about hole size and placement but it is possible. Image from Wikimedia Commons enter image description here
  • Rather than replace the broken bit of wood, you could route it and the chair leg for a loose or floating tenon, since it appears that the broken bit of short grain is to the inside (non-visible part) of the chair. Or use dowels, but much longer dowels than you illustrate. Either approach is daunting for an inexperienced woodworker. – Ecnerwal May 7 '17 at 2:29
  • I agree, that is an option, and given how subjective skill level is I just wanted to shoot out a more few options. – Gareth Shepherd May 7 '17 at 3:38
  • I think I could probably manage the repair 2) by driving a dowel through the rail. How long should the dowel extend pass the break? How thick should it be? – KZ. May 7 '17 at 23:36
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    @KZ.If you're going with dowelling (one of the best solutions) you should go with two dowels, not one. Only one gives much too much potential for the joint to rotate, two prevents this. Extend the dowels at least twice their diameter into the top of the leg, but deeper won't hurt (max a couple of inches). Be careful to drill square! Also make sure in advance that your drill matches your dowel closely, a loose fit will not make a strong joint. Dowel diameter should be half of the leg thickness or slightly better with hardwood dowels. – Graphus May 8 '17 at 7:25
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    Can you please provide sources for your illustrations? It's good form :) – Ast Pace May 10 '17 at 1:29
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While it would be my preferred fix I think that you could get a satisfactory fix by gluing it back together with a high-quality marine epoxy. I would NOT use normal wood glue (Titebond or similar), but I believe that something like West or Entropy epoxy, with a suitable filler, would hold securely enough for normal use for a non-load-bearing piece like this.

Of course, you will still have the issue that the piece has grain runout in that area.

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    Just in general, the glue bond from PVA-type glues is every bit as good as that of epoxy given ideal conditions in each case — once you reach stronger than the wood itself you don't need anything better. A glue-only fix here would not be ideal however, regardless of the adhesive used because there's so much end grain glueing surface, which epoxy doesn't deal with any better than PVA or polyurethane. – Graphus May 9 '17 at 17:12
  • You ARE getting long grain here, though, due to the grain runout. (Look closely at the break in the photos. It's a split along the grain with no splintering and only a little compressed material.) What you aren't able to get is the clamping pressure that PVA requires. Epoxy doesn't need any clamping pressure and is gap-filling. – SaSSafraS1232 May 9 '17 at 18:05
  • I didn't say there was only end grain, I can see the split ;-) Even if we accept that flake and its matching scallop expose pure longitudinal grain there's only a tiny patch of it, looks to me to be approx the size of the pad of my thumb. We can't ignore that there is a fair amount of end grain exposed (relative to the total glue surface area) since that won't glue as strongly. And this is a chair leg/frame joint, fairly famous for putting a lot of stress on joinery. – Graphus May 10 '17 at 7:10

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