meet the relative complications of treatment and may also take advantage
of the panel structure itself.
Based on these considerations, the Mengs was placed on a side
edge with silicone paper and a length of pine batten beneath. The main
reason for standing the panel vertically was to make access to both front
and back possible during structural work. This approach (which is not a
new concept) is practical in some cases.^45 To minimize restraint and allow
the panel to adjust position, it was occasionally lifted slightly at one end.
The relatively straightforward rejoining problem of the Mengs
was especially suited to a vertical orientation. The Palmezzano, in con-
trast, had a high number of fragmented splits and generally more compli-
cated treatment demands, which made a horizontal orientation preferable.
Apadded support table and rejoining apparatus were designed and built to
allow all-around access and control.
Ideally, to improve access and stabilize the panel before rejoining,
all moisture barriers and restraints, including unnecessary and nonoriginal
glue layers,^46 may be removed to allow the entire panel structure to stabi-
lize. This measure may not always be possible with larger panels, where
equilibration may have to be limited to the general area surrounding the
wood to be treated. It would have been difficult to treat either panel safely
with all previous restraints removed, though such a proposal would be
more feasible for smaller panels (Brewer 1994b).
In some cases, advantage may be taken of the immobilizing effect
of previous reinforcements during their removal to maintain some struc-
tural stability while rejoining large panels. Working from the proper top of
the Mengs, the balsa laminate and most of the wax-resin were removed
from each successive plank pair to be rejoined, leaving the remainder still
covered and the next disjoin still bridged for stability. Each freshly exposed
plank pair was then left undisturbed for at least one week to allow some
equilibration of the panel’s curvature before rejoining. This approach
maintained greater stability while allowing adequate joining pressures to
be applied without disrupting the remaining disjoins.
Battens were removed similarly from the Palmezzano (Fig. 14).
This was done by working across the panel grain and reducing the battensP A S C L P P 465Figure 14
Marco Palmezzano, The Mystic Marriage of
Saint Catherine. The panel laid facedown on
a padded table during the initial stages of
removal of the previous reinforcements. The
tools are on the chair. Note that the removal
was begun from a side-grain (nearest) edge
and progr essed across the panel grain.