Series editors' preface - Wood Tools

454 Conservation of Furniture
Steel or wire wool is inappropriate for
smoothing uncoated wood because it tends to
leave metal particles behind. The combination
of steel wool and moisture will cause staining
on woods with any significant tannic acid
content. Steel wool comes in a numerical grading
from 4 (coarse) to 0000 (very fine) and is
often coated with oil- or silicone-based lubricants
by the manufacturer to retard rusting.
Lubricant-free grades are generally used in
furniture conservation. A range of nylon abrasive
pads is available from 3M.
Burnishing the surface or exposed edges of
a repair, which compresses the upper wood
fibres, may assist blending it in with the
surrounding original material. A wooden
burnisher with a concave or convex shape may
be useful. The inside curve of a gilder’s
dogtooth agate burnisher is particularly effective
on arrisses, where sanding will produce a
crude and inaccurate approximation of historical
wear. If the outer face of an agate
burnisher is used, it will need professional
repolishing before it can be used on gilded
surfaces. Burnishing can result in a more
reflective and faceted surface, a markedly
different effect from a surface that has been
abraded. The nature of the surface being
matched will determine whether this is appropriate.
Burnishing should be tested on a scrap
piece of wood to see if it gives the desired
effect and to ensure that it will not inhibit
subsequent stain or finish. Although abrasion is
often the most efficient and reliable way to
prepare a new surface, burnishing may aid in
rendering an appropriate surface texture and is
particularly useful on arrisses and irregular
shapes. Burnishing creams, paste and powders
should not be used on unfinished or opengrained
timber because they will lodge in the
grain, may be difficult to remove completely
and may interfere with subsequent coatings.
10.2 General techniques
10.2.1 Dismantling furniture
Dismantling furniture may be quick and straightforward
or very slow and complicated, depending
on the looseness of the relevant joints,
previous attempts to compensate for loose joints
such as nails or screws, and the complexity of
the joints used. Unless the joints in the object
are already uniformly loose, it is possible that
the process of dismantling may cause further
damage. The decision whether to dismantle may
take into consideration fitness for intended use,
potential vs. actual damage both now and in the
future, balancing minimum intervention against
the need for a satisfactory repair or the need to
separate components to achieve a satisfactory
adhesive bond.
The first step is to assess which joints are
loose, whether the object needs partial or total
disassembly, or whether disassembly will be
likely to cause excessive damage and an alternative
must be found. Joints in chairs may be
tested for soundness by grasping the base of
chair legs attached by a single rail and flexing
them slightly, towards each other and then
apart. Loose joints are indicated by movement
along the line of the joint. Each joint should be
tested in the same manner. This technique can
be applied to most objects with a frame
construction (characterized by the use of
mortise and tenon joints). Loose joints in box
construction (characterized by the use of dovetail
joints) will manifest itself in racking of a
carcase or by flexing individual joints. A single
slightly loose joint may be acceptable in a
museum object but may present a hazard in
domestic use.
If a decision is made to dismantle and there
is any potential for confusion about the position
of any component, each should be
marked clearly before proceeding. Masking
tape may be used on non-presentation surfaces
to mark the parts of each joint with corresponding
numbers. When working with circular
components it may be necessary to use
register marks or tape to ensure the pieces are
returned to the correct position. It may also be
necessary to record the original geometry of
components using templates and diagrams.
Whatever method is chosen the conservator
should ensure marks can be removed after
reassembly without damage to any surface
finish that may be present.
Chairs can present problems when the shape
of the seat has no 90° corner or the angle of
each corner is slightly different. It is important
to record these angles to ensure that the seat
will return to its original shape when it is
reassembled, especially if it incorporates a
drop-in or slip-seat. A simple solution is to