CHAIR REPAIR

Chairs are built of the most flimsy parts we see in furniture, and still expected to serve us unfailingly. When adequately maintained, a chairs' parts distribute stress evenly, and easily support hundreds of pounds. When chairs loosen, or are improperly repaired, stresses are not distributed evenly. Local overstressing and broken parts or the collapse of the chair with the occupant can result. Repairing a loose 20th or 21st century stile and rail chair requires disassembling all of the chair parts on a bench, cutting off the dowels and drilling them out, followed by re-doweling, or inserting new slightly larger dowels. The chair is reassembled by a cabinetmaker, who adjusts all of the joints to fit tightly, so the chair is tight without any glue. Then the chair is disassembled and re-glued, ready to last 50 or more years before the new dowels shrink and the glue fails, and the repair is necessary again.

Loose chair disassembled, dowels cut off and drilled out, and individually adjusted to fit tightly, so the chair is tight without any glue, then re-glued.

Old Joinery: Mortise and Tenon, or Platform Chairs, Lasted Hundreds of Year

From the start of the industrial age, engineering has taken its toll on chair designs. Construction of chairs from ancient times till the nineteenth century was generally mortise and tenon joined stiles and rails, or platform type chairs with a solid wood seat with all legs and spindles dovetailed into the seat platform. Either type of chair was capable of remaining sturdy long after the glue failed, with stiles and rails or legs and spindles interlocked with each other, with very sturdy joints. These chairs, common before 1800, lasted hundreds of years before needing significant maintenance. These chairs were built usually by hand, using hand saws and spokeshaves or simple craftsman-powered lathes.

Mortise and tenon chair neglected, broken parts nailed together and lack of maintenance:

Industrial Age Engineering Creates disposable Chairs

The advent of factory power systems, at first from water power, then steam and electric, enabled machines such as drills and saws to work faster and more cheaply than could be done by hand. During the 1800's mortise and tenon chair joints evolved into doweled connections between the stiles (legs) and rails. Initially 2" long by about 3/8" diameter, the 22 or so glued dowels in a dining room side chair installed by a cabinetmaker and adjusted to be tight without glue before gluing, could be expected to hold a chair together for 50 to 75 years. Eventually the dowels shrink as they dry out, and the glue fails to hold the wobbly joints together. The increase in productivity between a mortise and tenon joined chair and doweled, was more than 50-fold, creating compelling economics for the demise of the mortise and tenon chair.

By the late 20th century, expanding polyurethane glues, familiar to many as "Gorilla" brand glue, allowed the use of 1" long dowels, poorly fitted by unskilled labor or automated machinery. These modern chairs can be expected to last 2 years, to a maximum of 10 years before falling apart. Simply re-gluing such chairs as they were made will result in similarly short life lives. If the dowels are drilled deeper, and fitted by a cabinetmaker when the chair is rebuilt, a 50 year or greater life can be expected.

Chair Rebuilding- 18th Century Mortise and Tenon Joinery - Sometimes Delicate, but Strong

The best type of chair construction had mortise-and-tenon joints. Instead of wooden pegs connecting the seat rails to the arms and back, there is a "tongue" of wood (called a "tenon"), that projects from each seat rail into the "stiles", or legs and arms. The tenons are made from the same piece of wood as the rest of the rail. When the chair gets very old (typically over 100 years), the wood shrinks glue fails, and the joints loosen up.

To repair the chair, any upholstery must be completely removed to allow the frame to be disassembled completely, to become a pile of wood rails and legs on the bench. If there are any broken parts, then they are repaired at this time. Small missing elements might be repaired with "Dutchman inlays", or sometimes replication of parts. The seat rail below had severe powder post beetle infestation, and was incapable of supporting the legs properly, so was replaced. Then the glue is scraped away from the tenons and from the inside of the mortises that the tenons fit into, and veneer is glued to the tenons, to make them slightly larger, and adjusted to fit tightly, without any glue. Then when the frames are reglued, they will be strong for more than the next 100 years, as they have done most of their shrinking at the beginning. The joints of sound wood will be as strong as when originally made.

            • Broken chair repaired to safely stand up through many decades of heavy use.

Louis XV period side chair in poor condition, disassembled and repaired piece by piece:

A chair frame to be rebuilt must have any upholstery removed from the frame first. The webbing and platform tie the chair together, preventing restoration of the joints. Joints cannot be scraped free of glue, and the joints shimmed and made tight, or re-doweled and glued, if the upholstery is intact

Improper Repairs Cause more damage, and usually doom a chair

Improper "repairs", including injecting expanding polyurethane glues (like "Gorilla" glue) into joints on top of old glue, or worse yet installing metal angles, or nails or screws, are 3 month to 1 year "fixes". Inappropriate repairs are expensive no matter how cheap! Especially when the loosening is often accompanied by breaking, as only a few joints loosen at once, putting too much stress on too small an area or on too few loose joints. Screws and nails focus all the stress on a joint to a tiny area. Wood cannot stand up to such intense local stress, and these screws or nails serve as levers to break up the wood around it. After such a repair, breaks often are accompanied by major collapses. It is better to do no repair at all, then a "screw and nail" repair.