Series editors' preface - Wood Tools

350 Conservation of Furniture
fibres and also contribute to other degradation
reactions, such as acid hydrolysis, in which
water is involved. Particulate soiling lodges
easily in interwoven structures which may
then abrade the material, contributing to loss
of strength or the destruction of a surface.
Acidic pollutants in both gaseous and particulate
forms may also contribute to degradation
processes (Florian et al., 1990).
Cellulose is prone to enzymatic degradation
caused by cellulytic bacteria and fungi in
damp conditions, which can result in pitting
of the surface (visible under magnification)
and staining. Fibrous materials interwoven in
furniture are subject to biopredation by a
variety of insects which may feed on the
material or on coatings or dressings applied to
it. Wicker work seems to be highly susceptible
to attack by wood boring insects, both
furniture beetle and wood boring weevil. This
damage is evident because of flight holes in
the surface of the material and frass left
behind by the feeding larvae. The material
may be very much weakened by the attack
and may seem unnaturally light in weight if
the attack has been severe. The susceptibility
of this type of material may be due to the high
water content as the materials are soaked
before and during construction. Also, water
soaking or spraying was often advocated as a
renovative/restorative treatment during the life
of these materials. Good environmental control
is advocated as a preventive measure. Rushbottomed
seats are more likely to harbour
vermin than cane and rodents are a risk to
straw-work furnishings (Doussy, 1990).
Over a period of use the materials lose the
ability to recover shape and may become
‘seated’; that is the seat takes up a curve below
the rails. This puts extra stress on the material
in use causing rubbing along the rail edges
which may eventually become breaks. Sometimes
an area of weaving may break, which
leads to a rapid loss in strength of the
structure.
When in use, objects may be subject to
restorative or maintenance treatments. Some
such treatments might be described as popular
myths. For example, over-dry or embrittled
wood, leather and plant materials are each
popularly supposed to benefit from ‘feeding’
with oils or waxes. In fact, these treatments
are unnecessary and may inhibit moisture
regain and contribute to degradation reactions.
Alternatively oils, waxes, varnishes, dyes, or
paints may be applied to ‘revive’ colour or to
consolidate friable or delaminating materials.
Colouring does nothing to improve mechanical
strength and may lead to the impression
that material is stronger than it really is.
Attempts to repair an existing structure with
new material may result in additional and
unbearable stress being imposed on the existing
dry and brittle deteriorated original.
The recommended environment for rush,
reed and cane is a steady relative humidity
between 40% and 60%. In low humidity these
materials become brittle and at high humidity
are subject to bio-predation. A temperature
below 25 °C is recommended to avoid embrittlement.
Exhibition light levels of 50–100 lux
combined with the elimination of ultra violet
radiation are suggested. Acid-free, unbuffered
storage materials are preferred. Dust protection
is advocated as the structures are liable to trap
surface dust. Material should be checked twice
a year for pest infestation. For further information
on these materials see Florian et al.
(1990) and Doussy (1990).
Textiles
Textiles are under a variety of physical stresses
related to manufacture or construction, including
stretching and flexing. How well the textile
fibre responds and recovers from these
applied forces largely depends on the fibre
type, construction and condition. For example,
webbing constructed in reverse twill weave
with jute thread is most resistant to stretching,
an essential feature of seat webbing. This is
due to a combination of the fibre and weave
types. However, jute degrades very quickly
compared, for example, to linen. Therefore in
the long term, in the same environment, linen
webbing of identical construction would be
less resistant to stretching but more resistant
to deterioration. Either fibre in a plain weave
would be less resistant to stretching. The two
fibre types combined together in a plain
weave or reverse twill would possess a combination
of qualities. On ageing, stretched
textiles may no longer have the strength to be
re-stretched to the same dimensions (particularly
after wet cleaning). This is most relevant
if the intention is to remove and re-apply a
top cover to its upholstered frame. A fold or