Series editors' preface - Wood Tools

materials is their photochemical stability. They
do not yellow and discolour, they remain
removable in non-polar solvents and can be
distinguished from original materials. All are
suitable for brush or spray application. It has
been argued, however, that such materials,
particularly the high molecular weight synthetics,
do not replicate the original appearance.
Modern varnish manufacturers may produce
furniture finishes that are a blend of traditional
and modern materials. One example of a hardwearing
varnish that can be applied using
French polishing technique is called table top
polish (John Myland Ltd, UK), which contains
shellac, nitrocellulose and ‘some synthetic
resins’. This coating does not crosslink and
may be reversed in ketones and esters.
Adhesion of other coatings applied on top of
table top polish is often poor. Such coatings
may be applied on top of a traditional French
polished finish if a full grain surface is
required, as it is can be difficult to abrade
once the surface has dried.
13.7.2 Traditional materials
Wax
Wax has been used since antiquity as a protective
coating and imparts a soft sheen. It may
be applied directly to the wood or over an
extant surface coating. A wax coating is not
appropriate if a varnished surface is heavily
crazed or fragile. Wax layers tend to be thin,
photochemically stable, slightly acidic, easily
removed from varnished surfaces, have low
permeability to moisture and may help prevent
scratching of lower resinous coatings during
dusting. The properties of wax are discussed
in Chapter 4 and in conservation literature
including Horie (1992) and Mills and White
(1994). Abercauph (1998) has tabulated the
physical properties of some commercially
available animal, vegetable, mined and microcrystalline
waxes.
Sheraton (1803) refers to the use of beeswax
in combination with other materials including
pigment and copal varnish. Other historical
sources refer to the use of beeswax mixed
with colophony resin. Walch (1997) has
suggested, however, that the use of wax to
impart a ‘satin sheen’ to restored furniture can
be traced to a late nineteenth century
aesthetic. Such treatment, applied uniformly to
Conserving transparent coatings on wood 629
furniture from different periods and with total
disregard for historical accuracy, has continued
throughout the twentieth century and may still
be seen in many antique shops and auction
rooms.
Beeswax is usually the primary constituent
of wax furniture polishes. Although beeswax
has a melting point around 65 °C it softens at
37 °C and as a result handling tends to leave
the surface marred with smears and fingerprints.
Harder waxes may be added to
improve the working properties of a wax
polish, most notably carnauba wax which has
a melting point of around 84 °C but is very
brittle. Furniture polishers often prepared their
own wax polishes using beeswax, carnauba
wax and turpentine with the addition of finely
ground pigment or oil stain. Modern tubed
artist’s pigments are used by some to colour
the contemporary mix as these are finely
ground and already thoroughly wetted by their
oil media. The proportion of beeswax to
carnauba varies but the higher the proportion
of carnauba added, the more effort is required
to buff the polish to a soft and even sheen,
and the more brittle the final wax coating. The
proportion of carnauba wax may be varied
between 10% and 15% to produce a slightly
harder-wearing polish that is still easy to buff.
The proportion of solvent may vary between
roughly 50% to 60% depending on the desired
consistency of the final paste. The wax paste
may be prepared by melting shavings or
blocks of wax in a double boiler, removing
from the heat when melted and then adding
colouring material (if required) and solvent. A
soft thin paste may be made by adding one
part carnauba wax, three parts beeswax and
six parts solvent, whilst a proportion of 1:2:3
of these ingredients will produce a harder,
thicker wax paste for a more durable wax
finish. Turpentine was the traditional solvent,
though because this solvent contains turpenes,
which may leave insoluble polymerized
residues, many conservators prefer to use
white spirits or mineral spirits.
Proprietary formulations may include soft
cheap waxes such as paraffin as extenders and
solvents vary from turpentine to white spirit,
xylene or toluene. It is not always necessary
to clean a wax surface before applying a fresh
coating, since the application of a wax paste
partially dissolves the extant dirty material.