can be taken apart and rebuilt to suit most larger panels or be customized
for a particular situation. All three designs require a degree of thought and
planning in their application. However, they are relatively inexpensive,
given the control and flexibility they allow in the gluing process.
All of the designs utilize a type ofscrew clamp, sometimes known
as a hold-down clamp, to provide pressure (Fig. 2).^8 The screw clamp is
mounted on a sufficiently rigid beam, usually of right-angled-section metal
that is fixed in relation to the panel.^9 The spatial arrangement of the clamp
and beam determines the general direction of pressure. The clamps are
used primarily to achieve the desired alignment of joints in relation to the
general plane of the panel, that is, to reduce “steps.” They can also be used
instead of bar clamps to provide joining pressure—for example, where
greater directional control is desired.
The screw clamp can be attached to any suitably thick piece of
stock. The thumbscrew of the attachment device may be snugged securely
in position with pliers. The clamps are small enough to be placed closely
together, and they can be moved to any desired location along the mount-
ing beam. The screw shown can be adjusted through a length of about
20 cm. The circular swivel foot piece can be modified by padding or by the
attachment ofshaped pieces with various contact areas and rigidities in
order to spread the applied pressure as desired.Case description
Aseventeenth-century panel painting^10 was treated structurally for splits
from a cradle locked by glue that could not accommodate the painting’s
response to environmental fluctuations. The panel consists of two planks
joined parallel to the grain near the center. The grain is oriented vertically
with respect to the image. Two splits had occurred since cradling, shown
by the lack of glue or varnish in the splits. The splits were stepped to a
small degree.Order of rejoining
The panel, which was almost as thick as it had been originally, had been
cradled unnecessarily. The cradle was removed to permit access for rejoin-
ing and to serve as a preventive measure against further splitting. The
extent of splitting was small, with the splits closed at both ends.Smaller Apparatus
422 Brewer
Figure 2
Screw clamps. One is attached to a double-
thickness length ofright-angled-section metal.