Chair Repair – Repairing Failing Joints
Chairs are a lot like people. When they get old, their joints – especially those in their legs – begin to cause trouble. They loosen up, creak and, if ignored, may fail.
As soon as you notice symptoms of loose joints in any chair, take action. If you get on the case soon enough, the repair may be very, very simple.
To start, try soaking the loose joint with a preparation like Chair-Loc. This is a liquid sold in a squeeze bottle at any good hardware store. It’s not really a glue. Rather, it works by soaking into the fibers of the wood inside the joint, causing them to swell up. This tightens the joint and helps prevent the kind of wracking movement that would cause the joint to wear and deteriorate even further.
If you don’t get to the joint soon enough, a simple Chair-Loc treatment won’t work. If ignored, the wood fibers in the joint become so crushed and worn that they lose their elasticity. If you are dealing with a relatively inexpensive chair that has rectangular legs and stretchers, you can brace the joint with special reinforcers made just for this purpose. These are smoothly-formed right-angle braces that screw to both members of a joint to give it added rigidity. Again, most hardware stores stock these.
To use one, make sure the joint is drawn up tight, then screw the brace in place. It will be most inconspicuous if you place it underneath the stretcher, but for extra strength, you can use one on top as well. Be sure to drill pilot holes for the screws to eliminate the danger of splitting the wood.
These braces are OK for your everyday kitchen chair, but they certainly aren’t appropriate for quality furni ture. And they’re not much good at all on pieces with round legs and stretchers. Now your best bet is to disassemble the joint and repair it.
Most often you’ll be dealing with a mortise and tenon joint. The end of one piece, or a necked-down part of the end (this is a tenon), fits in to a hole (or mortise) in the other. After taking the joint apart, clean both the mortise and the tenon to remove all the old glue. In most cases, warm water and vinegar will work. Some modern synthetic glues are insoluble, however. You’ll have to remove these by scraping with a chisel or other sharp instrument. Just scrape off the glue. Try to leave all the wood intact.
After cleaning the joint, reassemble it and test the fit. If it is snug, let the parts dry overnight, then reglue. You have a couple of choices for glue. If the old glue came off with water and vinegar, use a liquid hide glue. This should be strong enough for the job, yet can be disassembled in the future if further repairs are required. Restorers of antiques almost always use hide glue for this reason, and to maintain the authenticity of the piece.
But if you are after maximum strength, you might use one of the slow-setting epoxy glues. This is fine for any piece that’s not a valuable antique.
If, when you test-fit the joint, you find it’s loose and sloppy, a simple reglue won’t really work. First you’ll have to tighten the joint. How? It depends on the joint.
If it has a rectangular tenon, one simple way to tighten things up is to glue pieces of veneer to the (cheeks) sides of the tenon. A good hard wood like maple works best. If you can’t find veneer locally, you can get it from Constantine’s, 2050 Eastchester Road, Bronx, N.Y. 10461.
Glue oversize pieces of veneer to one or both cheeks and clamp firmly, padding the veneer with blocks of wood to assure firm, even pressure over the whole cheek. Let dry, then trim to size and test for fit. If the joint is too loose, add another veneer. If it’s too tight, shave the veneer carefully. Aim for a snug fit, but don’t make things so tight that you have to force the joint together.
Once you are satisfied with the fit, glue the joint together.
If your tenon is round instead of rectangular, your best bet is to install a wedge. Using a fine saw, cut a slit in the end of the tenon, about three-fourths of the tenon’s length. Cut a gently tapered wedge out of some hardwood (a clothespin is a good source). The wedge should be a bit less than 1/8 inch thick at the thick end. Coat the wedge and the slit in the tenon with glue, and tap the wedge in place. Let dry, then trim off any excess wedge and test the fit. You may have to shave the tenon slightly to get it to go into the mortise. When the fit is good, glue the joint together.
Sometimes you’ll encounter a dowel joint, usually with two dowels. The best way to repair a loose dowel joint is to cut the dowels off, then replace them with dowels one size larger.
No matter what type of joint you are fixing, you’ll likely find yourself fixing more than one at a time. Joints usually fail in pairs (at the very minimum). To assure all joints are pulled up tight, use a web clamp, or fashion a tourniquet from some clothesline and a stick as shown in the sketch. Just tie a double loop of line loosely around the chair legs, insert the stick between the two strands and twist to draw the parts up. When you get the necessary tension, jam the stick against a stretcher to keep the tourniquet from unraveling.
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Tags: Chair loc, chair repair, chair repairs, chairs repair, fixing furniture