Drew's blog


Repairing Chairs

Chairs are the most mobile pieces of furniture and because of that movement and use they are also the most damaged piece of furniture.  Also contributing to the large number of damaged chairs is the fact that there are usually four chairs for each table, they just outnumber other pieces.  It would be difficult to discuss all types of chair repair because of the endless variety of styles and types.  There are some repairs that are common and with some guidelines that can prepare you for the problems you may encounter.

The most common problem with chairs is that of loose joints, next are broken parts then worn and missing parts.  Some chairs are easily damaged because of their delicate nature; others are damaged from excessive use and abuse.  Whatever the problem, they need to be repaired in order to prevent further damage; it must be at least stabilized.  As with other old furniture, only the minimum amount of work should be done and as much of the original as possible must be preserved and maintained these old pieces.

Chairs in the nineteenth century were invariably glued together with hide glue and after time drying out the wood and glue the joints sometimes fail.  Unfortunately modern strongest wood glue have been used to repair much old furniture and this can actually cause more problems that it attempts to remedy.  The glue is so strong that the joints don’t fail; the wood fails causing much more damage than a simple loose joint.  Do not use modern glues to repair any old furniture, always use hide glue, fresh hot hide glue is the best but you can use liquid hide glue which is readily available and much better than any modern glue for this purpose.  See Using Hide Glue.  Some modern glues can be softened enough to loosen the joints by soaking the joints with water, this is a drastic step to undo an incredibly unfortunate choice of glues.  People without experience do many repairs made to chairs and seldom are the joints properly cleaned, prepared and clamped.  If the chair has never been repaired with modern glues then you will be dealing with hide glue that was used on the original assembly.  Old hide glue does not necessarily need to be cleaned from the joints as the newly introduced hide glue will reconstitute the old glue and the joints should be just fine.  If you can expose the joints any loose glue should be removed, as should any dirt and debris that might have accumulated over time.

Some loose joints on chairs can be repaired while the chair is still together or if you determine that you can’t take the joints apart to do a thorough repair.  This is done by using a hypodermic syringe with a fine needle and hide glue.  Liquid hide glue works well and hot glue needs to be thinned in order to work in the syringe.  It also helps to keep the syringe in hot water to help lower the viscosity of the glue.  Insert the needle around the loose joint and push it in as far as possible and start injecting the glue into the joint.  Move the needle to a different position and inject until glue starts coming out of the joint on all sides.  The joints can be clamped, the chair squared; the excess glue wiped off with a wet rag and it is allowed to dry overnight.  While this technique works on simple loose joints it can be a lot of work to go around to each joint and inject the glue, so if it is possible to disassemble the chair it can make for easier and better restoration work.

If it is possible to disassemble all of the joints then it is important to label or number the parts so you can make sure they all go back in their original position.  Many old hand made chairs will only go together in one way, each joint being individually fit, so keep track of the parts.  Clean off the excess glue on the tenons and also in the mortices.  On some drilled round mortices you might be tempted to just use a drill and drill out the old glue.  This is not a good idea as the drill bit can enlarge the original hole leaving a sloppy joint.  I sometimes use a smaller bit to clean out the glue in the mortice then clean out any excess that remains.  I will sometimes take a proper sized drill bit and advanced into the hole by hand to insure that the mortice is completely clean and ready to accept the tenon.  Just be careful not to enlarge any of these holes.

Some spindles and legs that attach to the seat such as a Windsor chair go all the way through the seat and are wedged on the opposite side.  These wedged joints are usually quite strong but some can become loose with age.  If you have to remove one of these spindles you must first remove the wedge.  Choose a drill bit slightly smaller than the width of the wedge and carefully drill out the wedge.  Once a few holes are drilled you can use a small chisel to remove any remaining wedge.  When you make a new replacement wedge, make sure you match the material of the original and make it a little thicker.  Once you remove the leg, use a saw to clean up the slot for the wedge.  Some of these wedges were inserted into saw kerfs cut on the end of the spindles or legs.  Others are inserted in a split in the end of the spindle or leg made with a chisel, then the wedge is glued and driven into the end and cut off flush and finished smooth on the top.  Some spindles and legs are blind wedged and can present a problem, as the wedge will prevent the spindle or leg from being removed.  This is a good candidate for injecting glue into the joint with a syringe, as they can be difficult to remove even when loose.  Other chairs might have bellied tenons turned on the ends of the spindles or legs.  This barrel shaped tenon is inserted and glued into a mortice drilled in green wood.  As the green wood shrinks the mortice shrinks around the tenon and holds the spindles or legs securely.  This joint can come loose yet not able to be completely removed; again another use of the syringe can deal with this problem.

Some joints might be pegged to reinforce those joints and if the peg needs to be removed, this should be done carefully.  If I have to remove an exposed peg or dowel, I choose a smaller drill bit and carefully drill down the peg or dowel.  Be careful even when using a smaller bit to make sure you are just drilling out the peg hand not into the chair itself.  Once you drill out the center of the peg it can be removed without damaging the surrounding hole.  Just break it towards the hole until all pieces are removed.  I then use a proper sized drill bit and gently by hand run it down the hole to clean off any pieces of wood, glue or other debris.  I make the new dowel from the matching materials.

Repairs to seats are usually straightforward and require only cleaning the joints that have come apart and re-gluing and properly clamping until the glue is dry.  Some seats will develop spits in the wood or will have just minor cracks in the joints that need to be filled and stabilized.  Of course choose a wood that matches the original as close as possible.  Old woods such as walnut, cherry, maple and the softwoods will change color with age so select as close a color as possible, keeping in mind that the new wood will also eventually change colors.  I use a fine saw and run it through the split to make a uniform kerf for the replacement piece.  This will also help clean out the split and give a good gluing surface.  Cut the piece of new wood to fit into the kerf and carefully fit it up.  I always remove any excess from the new piece so I don’t have to work it much after it is glued in place.  This protects the surrounding surfaces.  I then glue and clamp the replacement wood in place, clean up the excess glue and allow to dry overnight.  I always clamp even the smallest pieces to insure a proper bond of the new materials to the old.

Any damage should be repaired as soon as possible after it occurs to insure that any broken edges are sharp and crisp.  A fresh break is easier to repair requiring less touch up than an old break where the fresh edges have been rounded over.  Make sure that everything is properly lined up when you clamp it into final position.  It might shift and dry in the wrong place and that is one of the advantages of hide glue is that it is reversible if a problem arises.

Broken spindles, stretchers, rails, arms and legs need to be repaired in order to stabilize the piece and also to make it serviceable.  Instead of replacing broken parts it is always important to maintain the integrity of the piece by properly repairing them to preserve their history.  The damage and the repairs are all part of the provenance and heritage of old furniture and they need to be done in a neat and proper manner.

Turned members such as legs, spindles and stretchers usually break at their thinnest place or on the tenons on the ends and are usually perpendicular to the grain.  Lateral fractures along the grain are fairly easy to repair by cleaning the break and re-gluing.  The longer breaks provide good glue surfaces making repairs fairly easy.  Cross grain breaks require reinforcement in the form of an internal dowel peg.  This requires drilling a hole down the end grain of both broken parts in the exact center of each piece to a predetermined depth.  A dowel is made to the exact length of both holes less about 3/32” to1/8” to allow for glue.  If it is too short it won’t provide enough strength and if it is too long it will prevent the break from coming together.  I slightly chamfer each end of the dowel to make assembly easier.  The dowel and hole should be sized to provide enough internal strength as well as leaving enough wood around the hole to provide proper strength there as well.  I usually make repair dowel pins from straight grain hickory, which has the best strength, is flexible and glues well.  While I usually always match wood species, for hidden dowels I will select a wood that will replace the integrity lost when the piece broke.  Dowels can also be used to reinforce flat broken pieces such as rails or square legs, spindles or broken seats or failed butt joints.  These holes must be exact and match each other in order to make a proper repair.  Take your time and carefully locate the center of the turned spindle.  The broken end grain can be difficult to get a bit started so I always use a small gouge to excavate a starting point for the drill bit.  It is also very important that the hole is drilled straight down the spindle along the center axis.  I also countersink each hole slightly to provide a space for the glue and to make assembly a bit easier.

A very common problem with turned parts is tenons that have broken off in other parts.  While some of these can be removed and doweled back onto the end of the spindle most are lost when trying to extricate them from the mortice.  If I can remove them, I clean the broken area and glue and clamp the short tenon back onto the spindle, wipe of the excess glue and allow to dry overnight.  The next day I carefully drill down the tenon into the spindle with a proper sized drill to a depth 2 ½ times as long as the tenon.  I then glue in a dowel of the same length to reinforce the joint.  All to often the tenon is lost when removed and needs to be replaced.  I select material that matches the original and turn up a new tenon with a step down and a turned tenon to act as a dowel.  Then the end of the broken spindle is squared off and a hole is drilled down the center axis of the piece to a depth slightly deeper than the length of the turned dowel on the end of the tenon.  I then clean out the hole, apply glue and clamp.  I clean off any excess glue and allow to dry overnight.  

Sometimes the end of the spindles that have broken off tenons are themselves cracked or split and this may need to be repaired before a new tenon is glued back on.  I open up the splits as much as possible, clean them out if necessary and introduce hide glue into the splits.  I then use waxed string or cord to tightly wrap (served around) the splits forcing them back to their original position and holding until the glue dries.  The wax prevents the string from becoming glued to the spindle and after it dries, the glue on the surface is cleaned off with a damp cloth.  I have also used hose clamps of various sizes but the metal parts need to be protected to prevent the hide glue from rusting, if you use this use waxed paper in between the clamp and the wood.

When I glue the spindles back together I use a bar clamp to hold them from each end and gently apply just enough pressure to bring the break tightly together.  I check to make sure that the spindle is perfectly straight.  I have even used my lathe as a clamp by centering up the spindle and applying pressure with the tailstock.  I can turn the work by hand and make sure it is perfectly oriented.  Do not apply too much pressure or you can break the spindle, usually at the weakest part around the drilled mortices for the dowel.  Wipe off the excess glue and allow to dry overnight.

Missing spindles and legs should be made from matching materials and should exactly match the original missing parts.  Some old turned parts have become slightly oval in profile after years of drying out.  I always try and match the surfaces of other parts so I add wear and age in the proper places to imitate the use it would have received over the years.

Legs on old chairs can be worn off on the bottoms from frequent use over the course of their history.  If it is determined that the bottom of the legs need to be replaced matching wood should be chosen and you need to figure out what the original might have looked like.  Examine books and original examples to decide how to best shape the missing part.  I use the same method for adding turned leg ends as I do for replacing broken tenons on the ends of spindles.  I turn a new part and it has a shoulder that steps down to a tenon that is centered in the new foot of the leg.  I drill a hole centered in the bottom of the squared off leg.  You loose a little wood when you square off the end, if it is a real steep angle that the leg has worn off, I will sometimes just flatten it then shape the turned shoulder to match the flattened but not square bottom.  A square bottom on the leg is the easiest method for making a good serviceable repair.  The hole is drilled slightly deeper than the length of the shouldered tenon.  I also turn a slight chamfer on the end of the tenon and slightly countersink the hole on the top edge for a space for glue and ease of assembly.  I apply sufficient glue on both the tenon and the mortice as well as the shoulders and clamp the leg and check for straightness.  I wipe off any excess glue and allow to dry overnight.

Rocking Chairs present the usual problems of loose joints but they can also have broken or heavily worn rockers.  In the West most all of the chairs made during the pioneer period before 1869 were constructed of pine and other softwoods and were painted and grained.  Many of these old rockers have flat spots on the bottom of the pine rockers making them quite thin in the middle.  I clean off the bottom carefully before using any fine hand tools to flatten them out.  These old rockers can have rocks and other grit pressed into the wood and this can damage the cutting edge of hand planes and chisels.  I flatten the wood, then add on enough wood to be able to reshape the rocker to its original shape.  I rough the surfaces with a keying or toothing plane or a rasp to provide extra glue surface area to make a tight fitting, long lasting joint.  I apply glue, clamp, wipe off any excess and allow to dry overnight.  The next day I mark the shape of the rocker on the new wood and shape it to its final outline.

I do all of the repairs to the individual parts first before I attempt to reassemble the chair if that is possible.  When ready to assemble the chair I always warm up the parts to make using hot hide glue a little easier.  I will usually dry fit everything together to make sure I am not going to having any surprises when I am gluing up.  I have all of my clamps ready, make sure the joints are all clean, the glue is hot and fresh then I begin my intense clamping moment.  I do not like to be disturbed when I am gluing, I need to focus all of my attention to the situation at hand.  Make sure there is sufficient glue to coat all surfaces that come in contact with other surfaces.  Use plenty but you can use too much in mortices that can cause hydraulic problems when trying to force the tenon into place.  Trapped air can also cause problems of not allowing the parts to go together.  This is when it gets exciting.  You can twist the spindles or legs a bit to break the seal and allow the air or excess glue to come out as the chair is clamped.  Too much glue might require the joint to be opened and the excess glue removed, so be careful when applying glue to mortices.  Get all of the parts together as soon as possible after the glue is applied.  Apply the clamps and use the proper pressure for each application.  You can also clamp pieces too tight, squeeze out all of the glue and starve the joint, so be careful.  Check and make sure everything is fitting properly and make sure that the chair is sitting on a flat surface as it dries to insure that the chair won’t rock or wobble.  A weight on the seat can help hold the chair flat.  Also check for squareness and other angles of legs and backs as is appropriate for each individual chair.  Wipe off all excess glue and allow to dry overnight.

If a chair is upholstered then it is better to do the repairs without taking the chair apart.  You may have to remove part or all of the upholstery for some repairs, so you either need to become familiar with these techniques or have a professional remove the upholstery, you can do the repairs then have it reupholstered.  If you do the work yourself, make careful notes on how you take the upholstery off.  This allows you to properly put the upholstery back on the way it was originally.  Try and keep the original upholstery material, if you are going to put new fabric on, put it on over the original material to preserve it with the chair.  I tighten up any loose webbing on the chair, clean the padding materials of dust and clean the fabric (using proper techniques) if necessary.

You will encounter many types of damage on chairs, from being over weighted to being chewed by animals.  You will find breaks in places you wouldn’t think the wood could break.  You will find chairs that are in excellent condition with only a few loose joints or you might get a sack of parts that barely resemble a chair.  I have had to undo many poorly done repairs and have worked on chairs that have been repaired so many times that none of the joints have sharp edges and all are very loose when assembled.  You may have to get creative by wrapping tenons with string or cloth and a lot of glue to make these joints serviceable.  You will be required to improvise ingenious clamps where normal clamps won’t work.  And, you will never run out of chairs to repair, so repair them in a neat and proper manner using original materials and techniques to preserve the integrity and maintain the history of the chair.