Most furniture is assembled with
glue, flush or mortised joints, screws and nails. Repairs are
usually a matter of remaking joints using a method or material
similar to the original, but some reinforcing is often necessary.
Any joint that depends on fitting
one component into a hole in another is a mortise joint. Joints
between table legs and frames are usually mortised; most wooden
armchairs have some mortise joints; all legs with rungs, whether
squared or turned, use mortises; and almost all traditional dining
chairs use mortise joints between frames and back crosspieces, and
in the seat frame.
When chair joints loosen, do not
wait till stress cracks the legs around the mortise holes. Spring
the frame gently with hand pressure to release the crosspiece from
its mortise, then clean off the respective faces and apply a
liberal coat of a strong gap-filling glue such as 308 Glue. Slip
the joint back into position, and use a webbing strap around the
frame to maintain an even light pressure while setting. Wipe off
excess glue while wet and allow adequate setting time. A majority
of repairs can be dealt with as simply as this.
If opposite joints are loose,
disassemble with light blows of a rubber or a wooden mallet or use
a piece of heavy corrugated card or softwood packing to avoid
surface damage. Then renew all joints as before.
Always stand a chair or table on
its legs with a light loading of books or bricks while glue is
setting, to maintain the leg alignment.
 Large
mortise joints in beds and tables often develop cracks running
into the mortise itself before the damage is noticed. Disassemble
the joint with care, then open the crack with a thin wooden wedge
and pour in 308 Glue. Clamp lightly till set. Then clean out
mortise, glue all surfaces and replace the joint. Then, with a
power drill, drill a 6 mm hole through both sides of the cracked
area, either clean above the mortise or through mortise and
tongue. Wipe the glue off the bit before it hardens!
Cut a 6 mm dowel stick to length,
dip in glue and drive till firmly seated. Make sure the mortise is
kept tightly closed throughout this operation and clamp, weight or
bind till next day. This pinning operation will rescue most loose,
cracked mortises if the timber is of reasonable size.
Where furniture is assembled using
screws or nails and particle board, or by attaching metal
reinforcements or other components, such as in convertible day
beds, the replacement of loose screws can be a problem, for they
must be re-seated in the old holes.
Remove the screw or screws and
clean out holes thoroughly. If the joint is not under stress fill
the holes with epoxy repair cement or Araldite type product and
replace screws in the wet stopping. Clamp till dry.
Where there is any stress in the
joint, fill the hole firmly with epoxy cement and let set hard.
Re-drill a pilot hole and replace screws. If the screws are
rusted, replace if possible with self-tapping screws of the next
heavier gauge if the fittings will accept these.
Flush joints, where timber is
butted and glued, are weak and when repairing these it is usually
best to use a combination of fasteners like nails or screws, and
glue. Use wood filler to cover nail or screw heads, taking these
down about 3 mm below the surface first.
 Outdoor
furniture and some heavy indoor furniture is assembled with
plug-type joints, where a heavy plug, dowel or tongue is driven
into a blind hole and held in with glue. These joints often loosen
with contraction of the wood as a result of heat or dryness.
When repairing, a wedge can be used
to tighten the mortise but this job should be tackled with care.
First, a saw cut must be made in the plug, cutting centrally down
the grain no more than half the depth of the plug. Do not use this
method with a shallow plug in a brittle wood such as pine.
Cut a thin wedge as wide as the
plug and nearly as deep as the saw cut, and no more than half as
thick again. Bevel the edge with a chisel. Slip the wedge into the
cut and try fit. The plug should go almost home, but not quite.
Withdraw the plug, adjust the wedge if necessary, then coat the
wedge with glue and insert it loosely. Coat the plug with glue and
drive home. The wedge slightly expands the plug to a tight fit.
Make sure that the direction of the wedge is across not along the
grain of the mating piece, or expansion of the plug may crack the
member into which it is inserted. |
