glue alone would seem adequate. Various mechanical fixings, such as bat-
tens, loose tongues, tongue and groove, or dovetail keys might also be
employed. Battening serves to resist warping as well as to hold several
boards together. As G. Heine (1984) has demonstrated, a particularly
effective method is tapered dovetail battening, which holds firmly in all
directions while permitting a certain amount of shrinkage (Fig. 15). Muller
has recorded that both Florentine and Sienese composite panels are found
with internal dowels (Muller 1993). However, properly applied to well-
fitted joints and protected from damp, the traditional animal glues have
proved their strength and durability over many centuries, even on edges—
such as the backs of stringed musical instruments—that are much thinner
than those of panels for painting.
Finally, the now-solid board of required dimensions needs a finely
smoothed surface to receive the paint. Since geometrical accuracy is no
longer as important as in the preparation of the joints, the first approach
to this task is with a short plane for smoothing, some 15–20 cm long. If
the wood has been carefully selected and does not present any wild or
contrary grain, the smoothing plane will achieve a surface ready for
finishing with abrasives. If, however, there is difficulty with the grain tear-
ing out in places under the plane, then recourse will be made to scrapers,
such as pieces of broken glass or, more recently, thin steel plates the edges
ofwhich have been turned to form microscopic hooks.
The ultimate finish has always been achieved by abrasion. The
ancient Egyptians used stone rubbers. In Europe various dried fish skins,184 Walker
Figure 14
Roubo’s illustration for the making up of pan-
els (Roubo 1769:pt. 1, pl. 18). At the bottom,
four boards are marked so that they will be
kept in the intended order and relative posi-
tion when they are trued and glued. There are
clamping devices to hold them together while
the glue is setting, glue pots and brushes, and,
at the top, tonguing and grooving planes with
their cutters, in case it is desired to joint the
board edges in this way.
Figure 15
Routing out of the housing across a multi-
section panel, as part of the installation of a
tapered dovetail batten (from G. Heine’s
article on historical and technical aspects of
tapered dovetail battens [Heine 1984]).