Series editors' preface - Wood Tools

10.2.4 Reinforcing joints
If a loose joint has been treated so that it is
well adhered with closely mating surfaces,
reinforcement with fixings such as nails, screws
or metal brackets is unlikely to be necessary.
Such fixings have often been employed by
amateurs in an attempt to reinforce loose or
weak joints. Some, such as screws and nails,
inevitably lead to substantial further damage to
loose joints, whilst the effect of others, such as
obtrusive metal brackets, have met with varying
success. If the underlying problem of the
loose joint is not addressed all these methods
will result in substantial further damage to the
joint and the surrounding wood as leverage
forces become concentrated on a small area of
contact around the fixings. Fixings such as
screws and nails are often difficult to remove
without widening the area of damage.
If screws or nails are part of the original
construction of the object, as a general rule
they should be retained in their original positions.
Adhering small blocks of wood along the
grain may strengthen a joint when no other
option exists. When applied with animal/hide
glue they are readily removable without
damage to the original.
10.2.5 Frames
The construction techniques used in frames are
similar to those used in joinery and cabinetmaking.
Corner joints in frames may utilize
mortise and tenon joints that may incorporate
one mitred side or pegs, lap joints that sometimes
have a mitred side, and simple mitres
that may be reinforced with wooden splines
cut into the corner or a wooden wedge at the
back. Frames were usually integral to panel
paintings until toward the middle of the
fifteenth century, when the two forms were
separated (Newberry et al., 1990). Most mirror
and picture frames utilize wood as a substrate.
The decorative materials and techniques used
to enhance them are similar to those found on
furniture. The conservation problems that
apply to frames are often analogous to those in
the broader discipline of furniture conservation.
Frames were usually made to enhance the
presentation of a specific work of art, and often
also functioned as an architectural element
within the broader context of an interior
Principles of conserving and repairing wooden furniture 459
design. This symbiosis may be an important
consideration for evaluating the degree of
treatment necessary for the conservation of a
framed painting or mirror. In the case where a
painting or mirror and its frame are both to be
treated, the aesthetic balance between them
should be maintained. From the third quarter
of the eighteenth century and onward, composition
became a popular material for the
surface decoration of gilded frames (see
section 10.5.7). An introduction to the history
and stylistic development of frames may be
found in Jacob (1996), Newberry et al. (1990)
and van Thiel and de Bruyn Kops (1995).
Mendgen (1995) examines nineteenth and
early twentieth century frames whilst Baldi et
al. (1992) offer excellent illustrations, including
profiles, and an introduction to the restoration
of frames.
Handling mirror frames
Structural factors and the condition of surface
decoration should be considered before
handling and moving mirror frames. Handling
carved mirror frames may be problematic
because there are often few, if any, handling
points that do not involve applying pressure to
fragile elements of the frame. The frame itself
may not be structurally sound as a result of
adhesive failure due to excessively low, high or
fluctuating RH, insect infestation and minimal
fixings that may have corroded. In addition,
mirrors may contain multiple sheets of glass
that are often not securely fixed to the frame.
There is a danger of catastrophic failure if a
mirror is moved, particularly as it is moved
from a vertical to horizontal plane. Mirror
plates are sometimes held in place with glue
blocks, which may also be pinned. The glass
may break if it shifts and comes into contact
with these pins. The frame should not be relied
on to hold the weight of the mirror if it is
placed face down. Thus a frame should not be
moved from a vertical to a horizontal position
without taking into consideration the construction
and stability of the frame, the change of
weight distribution and pressure points, movement
of panes and the way in which they have
been secured. It may be necessary to provide
support for glass and fragile decorative
elements on the frame. Dowling (1999)
describes a system for the removal and installation
of mirrors, which ensures they are kept