The Structural Conservation of Panel Paintings

In panels with multiple splits, some running the entire length of

the panel, it is preferable to rejoin each section first. This is partly because it

becomes more difficult to control the procedure as the size of each section

increases. Joining pressures must be directed over increasingly greater spans,

and sections with unconsolidated weaknesses, especially larger sections, are

more difficult to manipulate than those that have been consolidated.

Apparatus description and application

Construction

The apparatus is supported by a table frame with crossbars (Figs. 3, 4a, b).

In order of assembly, a single alignment frame is made first from two

equal lengths ofright-angled-section aluminum, for lightness and sufficient

rigidity. The aluminum lengths should be cut at least 50 mm longer than

the dimension of the panel that is parallel to the intended joint. The

lengths, which determine the maximum size of panel that can be treated,

are drilled at each end and bolted together with two shorter lengths offlat

metal to make a rectangular frame. Two such frames, one for each side of

the joint, may be necessary to achieve sufficient control of joint alignment

perpendicular to the panel plane.

S R M  P P 423

Flat

metal

4

Panel

C-clamps

Table

Bar clamps frame

Threaded

rods

Wooden

beams

Right-angled-section

metal

1

Alignment

frames

3

2

Figure 3
View of the smaller rejoining apparatus, in
which the order ofassembly is as follows:
(1) build and attach the alignment frame(s)
to the table crossbars; (2) place two parallel
wooden beams on either side; (3) join the bar
clamps with threaded rods and place on the
wooden beams, through the alignment
frame(s); (4) position the panel and adjust sup-
ports, clamp positions, and pressures. (To sim-
plify the diagram, only one panel member is
shown in position, and the bar-clamp stops
are not padded.)

Figure 4a, b
Cornelius Janssens (or Johnson), Portrait of the
Third Earl of Moray,seventeenth century. Oil
on oak panel, 807 3640 3 7 mm thick.
Private collection, Scotland. HKI treatment
no. 1475. A view(a) of the rejoining proce-
dure shown from above an end-grain edge.
Note the restraining bars to the left and right
ofthe alignment frames, attached with
C-clamps to spacer blocks and the table frame
below. A view (b) from underneath the mid-
dle of the panel shows the alignment frames
and six screw clamps fixed to the table cross-
bar with C-clamps.

a b