The second type of pressure, alignment pressure,may be sub-
divided into two categories. Out-of-planealignment describes pressure
applied roughly perpendicular to the general plane of the panel to bring
the two sides of the joint to the same level.^2 In-planealignment describes
pressure applied parallel to the joint axis, primarily to bring the elements
of the image into register on either side of a complete disjoin. In-plane
alignment can usually be achieved by maintaining the position of the two
panel members carefully by hand during the rejoining procedure. More
control may be necessary with smooth-faced disjoins, where slippage is
more likely under pressure.
The amount of joining pressure required is determined by the
panel’s condition. In most cases, much less pressure is used than would
be needed for a construction joint. Panel paintings do not require high
pressures: pressure should be just enough to bring the joint faces snugly
together. If correctly chosen and applied, the glue fills slight gap variations.
Too much pressure is dangerous: it can distort the panel and joint, increas-
ing the possibility of damage to the paint and the structure of the wood.
In fact, some conservators prefer not to apply any pressure during
rejoining to avoid initiating stress. Of course, depending on environmental
conditions following treatment, joints made without the application of
pressure still undergo some internal stress. The use of pressure may also
be defended for the following reasons: (a) pressure can be beneficial to a
good glue bond, and (b) a poorly aligned joint is usually difficult to putty
and retouch satisfactorily, especially when a panel painting has a pristine,
glossy surface. Therefore, the application of modest pressure to achieve a
better joint and alignment may be worth considering.Various systems of wedges and screws with pressures borne by rigid beams
have been developed to control alignment pressures. Weights can consist
of loosely bagged sand or metal pellets, for example. With practice, such
methods can be used with considerable success, though there are usually
drawbacks. For one thing, the bulkiness of some apparatus interferes with
access and control. Moreover, the careful setting of wedges can be frustrat-
ing and tedious and cannot be quickly and easily reproduced if the panel
members need to be moved prior to gluing. Sophisticated, ready-made join-
ing tables that address many such problems, however, can be purchased.
Another approach to rejoining uses (usually) V-shaped wooden
inserts that are glued into channels cut along the line of splits or disjoins.^3
This method will not be discussed here in detail (see Bergeon 1990; Uzielli
and Casazza 1994; see also Uzielli, “Historical Overview,” and Rothe and
Marussich, “Florentine Structural Stabilization Techniques,” herein).The rejoining procedure is often technically demanding. For example,
although there is a choice of adhesives that vary in ease of reversibility, the
difficulties inherent in reversing a dried joint usually involve considerable
risk to the structure ofthe painting, making it desirable to “get it right
thefirst time.” For this reason, control and access are important.
Even the simplest rejoining cases may prove stressful to practition-
ers—this author being no exception. The critical nature of the procedure
demands a purposeful, well-planned approach, the necessity of which canPrecautions and
Suggestions
Approaches to Rejoining
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