Series editors' preface - Wood Tools

Extended exposure to polar solvents of the
underside of a flake may soften the lacquer
sufficiently to allow it to be eased back into
place with small weights or a heated spatula.
Unfortunately extended exposure to polar solvents
may also cause significant damage to the
surface of the lacquer.
Flattening distorted lacquer
General techniques for cramping are discussed
in section 10.1.10. The traditional Japanese
method for cramping consolidated lacquer
deserves a brief mention. Flexible sticks braced
against a frame to apply pressure to lacquerware
objects are called shimbari (Figure
16.25). The amount of pressure applied
depends on the thickness of the stick and the
degree to which it is bent. Foam or small
pieces of rubber can be used to protect the surface
and prevent the sticks slipping. The use of
small pieces of Perspex allows the conservator
to see the surface as progressive cramping
pressure is applied.
Flakes, cups or tenting may be flattened
incrementally, after humidification, by introducing
a small amount of ethanol or a blend
of 95% ethanol and 5% water to the underside.
Shimbari can then be used to apply very gentle
pressure, flattening the distorted lacquer by
0.5–1 mm. The pressure and the humidified
state of the lacquer should be maintained for
some time, depending on the thickness and
condition of the lacquer. The process is
repeated until the distorted lacquer is flat and
can be adhered to the substrate.
If an area of a lacquer surface has become
fragmented, the pieces may be assembled
using tiny pieces of transparent pressure-sensitive
tape. A thermoplastic adhesive may then
be applied to the underside and the ground
and the whole relaid in a manner appropriate
to the chosen adhesive. The amount of adhesive
applied should be just sufficient to
adhere the lacquer to the object. Excess pressure
may force adhesive out onto the surface,
where extended contact during drying may
damage the lacquer. A thermoplastic adhesive
will allow the additional use of a heated spatula,
isolated from the surface with
Melinex/Mylar, during the consolidation treatment.
Any remnants of adhesive from pressure-sensitive
tape may be removed with a
hydrocarbon solvent.
(a)
(b)
Conserving other materials II 767
Figure 16.25 Shimbari
(a) Applying shimbari to a nineteenth century Japanese
lacquer tea table
(b) Detail of shimbari used to apply pressure to a
lacquer surface. Consolidation utilized traditional
materials (mugi urushi)
Materials
Webb (1995, 1999, 2000) has reviewed the use
of synthetic consolidants for lacquer. This section
identifies problems that may be encountered
and approaches that may be used when
consolidating Oriental lacquer. The advantages
and disadvantages of various materials used for
consolidation are discussed in section 12.2.4.
Wax and wax/resin mixtures have been used
with varying success in the past but impart little
strength and are incompatible with most
other adhesives. These materials are not recommended
for consolidating Oriental lacquer.
Water-based consolidants are often useful for
consolidating lacquer because they can penetrate
and adhere well. Although some may be
used in conjunction with heat, the combination