As a woodworker, I'm often asked to repair furniture — especially chairs. While disassembling the chair, removing any glue residue, and then reassembling the joints is likely the best approach to the problem, there’s a risk of inflicting damage to the chairs if some of the joints are loose, but the others are not.
A better approach, then, is to just focus on the loose joints. Veritas offers a glue kit known as Chair Doctor Pro that I’ve had very good luck with.
The Chair Doctor Pro kit comes with glue, a syringe, and needles of three different diameters (You can also get a less expensive Chair Doctor kit that comes with a small bottle of glue and one needle.) But there’s a little more going on with this kit than meets the eye.
One nice thing about the Chair Doctor kit is that the needles allow you to keep the repair hidden. In fact, if a chair tenon is loose enough that you can insert the needle directly into the gap between the mortise and tenon, that’s the best way to apply the glue to the loose joint. In other instances, however, you may not be able to get access to the mortise that easily. For these situations, Veritas recommends drilling a small pilot hole with a twist bit either underneath or behind the mortise.
The glue has lower viscosity than your average wood glue. Once injected into a mortise, it flows out and fills any gaps between the chair mortise and tenon. Next, the thin glue soaks into the end grain and causes it to swell. This makes a previously under-sized tenon large enough to fi t the mortise tightly. The glue also dries quickly, essentially “freezing” the tenon in this expanded state and preventing future contraction.
After applying glue to the joint with the Chair Doctor syringe and needle, I recommend clamping the joint until the glue sets. I’ve used the kit on a few old chairs of my own, and I’ve found it to be a good, simple solution that’s a lot less work than completely disassembling the chair.
