Series editors' preface - Wood Tools

e progressively tightened over the next ten or
fifteen minutes, gradually applying more pressure
to the veneered board.
Veneer on components with a curve in one
plane can be laid using a veneer hammer or by
using negative formers made from wood or a
plaster cast made for the purpose. If a cast is
needed, an sandwich wrap or Teflon sheeting
of the type used by plumbers to wrap pipes
may be used as an isolating layer. Modelling
clay (e.g. Plasticene) can be used to create
walls for the plaster. Mix the plaster with water
according to the manufacturer’s instructions
and pour. A loose woven material, such as
upholsterer’s scrim, may be used to reinforce
the plaster. Allow it to set, then remove the
mould and use it to cramp the veneer into
place. An unreinforced cast will be brittle and
it is advisable to use a piece of waste wood to
spread the cramping load evenly on it. It is
sometimes possible to compensate for curves
by padding out a former that does not fit
exactly. This may result in uneven pressure
and when the glue has thoroughly dried out,
unevenness may telegraph through the veneer.
A quick and effective gluing caul can also be
made using an oven hardened PVC gel such as
Sculpey or Fimo to make a quick mould.
Complex curves may be cramped using
heated sandbags. Woven cotton bags are filled
with sand until about two-thirds full. The bags
are then stitched closed. They need to be
heated in an oven (c.70–80 °C) for several
hours before use. The veneer is prepared as for
caul veneering but the heated sandbags are
pressed to conform to the shape of the ground
before a board is placed over them and cramping
pressure applied.
Whilst traditionally veneer was laid using
glue from natural sources, modern furniture
manufacturers utilize heated presses and
synthetic adhesives such as urea formaldehyde.
Small workshops may also have made use of
modern adhesives. Some, for example, have
used impact adhesive in an attempt to prevent
warping when veneer is applied to one
surface. Others have used PVAC wood adhesive
for veneered furniture that was to be
shipped to hot climates such as the Middle
East. In the case of PVAC, traditional methods
and modern materials were combined – the
PVAC was applied to the surface, veneer
placed on top and a hot iron applied until a
Principles of conserving and repairing wooden furniture 473
hiss was heard, indicating evaporation of
solvent. Although synthetic adhesives were
used in the manufacture of twentieth century
veneered furniture, problems of reversibility/
retreatability usually preclude re-using such
materials in conservation treatments.
10.4.2 Cleaning
Marquetry, boulle and complex designs
executed in veneer may be dusted with a soft
brush and the dust removed with a vacuum
cleaner. Feather dusters should not be used as
they may catch on loose edges and tear small
fragments free or, in the case of boulle, bend
brass up and crease it. White spirit or an
aromatic hydrocarbon solvent will remove
grease and finger marks. The presence of a
natural resin varnish can be detected with the
use of a hand-held UV light source (UV
goggles should always be used).
Traditional furniture revivers that contain
linseed oil are a significant source of damage
to marquetry and veneer. As the surface ages
small surface checks may form in the veneer
and surface finish. Small gaps may also open
up along saw cut lines. When reviver is applied
linseed oil penetrates these cracks and is
drawn by capillary action beneath the intact
surface finish. Linseed oil traps dirt that is then
incorporated into the macromolecular structure
formed over the years the oil takes to dry. This
accentuates the darkening associated with
linseed oil films. Repeated applications of
reviver often results in significant aesthetic
disruption of the surface, which becomes
blotchy and discoloured. In many cases reversing
such damage completely may be impossible,
although in some cases a selective
cleaning treatment may be successful (see, for
example, Philp, 1999).
Brass has often been selectively cleaned in
the past with the result that varnish may be
present only on the turtleshell. The wishes of
the owner or curator should be discussed
before any cleaning or polishing of the metal
is undertaken. Metal polish should not be used
for cleaning boulle. The ammonia present in
many proprietary products may darken the
substrate wood and cause irreversible staining.
The traditional method of cleaning the brass
has been to use a variety of abrasive materials
(e.g. charcoal or pumice). Engraving on the