Series editors' preface - Wood Tools

ducing the curves on boulle and marquetry
requires a relaxed and confident saw action. A
blueprint for a full size marquetry donkey,
usually used for cutting thick packs of veneer,
can be found in Ramond (1989).
The underside of replacement brass should
be cleaned, degreased and scored before it is
laid. If large pieces are to be laid it may be
helpful to warm them slightly before bringing
into contact heat-setting animal/hide glue.
Similarly sheet lead or zinc may be warmed to
extend the contact time before the glue gels.
More cramping pressure may be required if the
metal has any undulations, whilst flat brass
requires only medium pressure. After the glue
has set any excess on the surface may be
removed with a damp cloth. The metal
elements of boullework were often finely
engraved. In some cases it may be that not
replacing the engraving allows the overall
design to be read and easy identification of
replacement areas. In other cases lack of
engraving may be unacceptably obtrusive.
Producing repairs to boulle work is very
labour-intensive and the repair can be easily
ruined by poor engraving.
Pewter was utilized in boullework and for
metal stringing. Due to the toxicity of the lead
in tin/lead pewter, antimony began to be
substituted for lead in pewter in the eighteenth
century. Modern pewter, or Britannia metal, is
an alloy of tin (89%), copper (3.5%) and antimony
(7.5%). Tin is amphoteric, corroding
under both alkaline and acidic conditions. Care
must be taken when treating pewter because it
can corrode from underneath leaving a thin
skin on top that abrasion will completely
destroy. Replacement pewter can be cut accurately
with a cutting gauge and will require a
fine blade if sawn. It can be patinated with a
strong solution of acetic acid, which is rinsed
from the surface when the desired colour is
achieved. Corbeil (1998) reported the presence
of tin/mercury amalgam metal fillets on a
boulle clock case. The corrosion process of
such amalgams is discussed in the context of
mirrors (see section 15.5).
The decorative effect of marquetry and
veneer was often enhanced by the application
of chemical stains or dyestuffs. Sycamore
stained grey with ferrous sulphate, for example,
was known as harewood. The materials
used to stain wood have been considered by
Principles of conserving and repairing wooden furniture 479
Baumeister et al. (1997), Blanchette et al.
(1992), Roelofs (1994) and Thornton (1998b).
Materials and techniques used for colour
matching repairs to varnished wood are
discussed in Chapter 13.
Sand shading can create a three-dimensional
effect in marquetry designs. The original
should be examined to determine what degree
of shading is present and how far it extends on
individual pieces of veneer. Fine sand is heated
in a container deep enough to allow the
degree of shading on the original to be reproduced
without pieces of veneer touching the
bottom of the pan. Experiments on a spare
pieces of veneer will help gauge the right
temperature, exposure time and whether the
veneer should be pushed into the sand at an
angle. Sand shading often results in shrinkage
and it may be necessary to remoisten or soak
veneer pieces to expand them. The moisture
content of soaked pieces should be returned to
equilibrium with ambient conditions before
they are laid.
It may be helpful to lay a marquetry or
boulle repair in a single operation if it consists
of a discrete and complex design element, and
several approaches may be used. The design
element may be built up using gummed paper
on the underside. When the design is complete
a thin layer of glue may be applied to the
upper surface and the marquetry secured in
position with a thick paper placed between
weighted boards and left to dry. The gummed
paper can be removed by dampening the
underside slightly and, when dry, gluing the
repair into position. Excess glue that dries on
the adjacent surface may damage the finish and
it may be necessary to apply cramps, press out
excess glue, release the cramps and clean up
the glue before the final cramping operation,
which leaves the repair cramped up for the
glue to dry. Warmed glue blocks, slightly larger
than the area of repair, may be isolated from
the surface with Melinex/Mylar.
Alternatively, a design element may be built
up using pressure-sensitive tape on the upper
surface and, when complete, the repair applied
straight to the substrate. This prevents slight
movement that may result from the use of
animal/hide glue and paper, allows slight repositioning
if necessary and thus ensures a good
fit. If movement within the design element may
be a problem, a thin even layer of glue may be