Series editors' preface - Wood Tools

116 Conservation of Furniture
purposes or to increase their resistance to corrosion.
Generally speaking, the larger tacks and
staples are used to hold webbing, the smallest
and finest to hold the top cover. Metals include
iron, steel and copper alloys. Close examination
of tacks and nails may indicate the type of manufacturing
process (see Bradley Smith, 1966;
Neilson, 1968). Features to look for include
tapered and non-tapered shanks, uniform sizes
and shapes, surface burrs and striations, gripper
die marks and metal type. These features may
indicate techniques of manufacture and may
suggest a date. For example, uniform sizes with
flashes may suggest casting whilst identical features
may indicate machine manufacture. For
additional information on nails see Bodley
(1983). Identification of metals is discussed in
Chapter 5.
3.4 Understructures
Understructures include the support system of
webs, springs and fills. The understructure has
several functions. It provides comfort for the
sitter, it takes the weight of the sitter, it
enhances the design through the lines of the
frame, it prevents loose covers from slipping
off and it holds the shape of the object while
in use. Examples of different structures are
illustrated in Figure 3.8. Fills are shown in
Figure 3.9. These features, and springs, are
also beautifully illustrated in James (1990).
Individual materials and upholstery structures
have to withstand heavy wear over long
periods of time. The higher the grade the more
durable the product. In top-grade work,
materials of the highest quality would be used.
These include, for example, curled hair, linen
cloth and webbing of flax, cotton, jute and
hemp. Attention would also be paid to detail
(historical correctness in profile and fabric,
trim, seam construction etc.). Such work will
last well but can involve much hand work. In
low-grade work, materials would be of lower
quality and might include coir fibre, Algerian
fibre and, in particular, foamed plastics, jute
cloth, textile waste, adhesives and poor quality
staples. Such work will not stand up to heavy
use. Lower-grade work may involve use of preformed
units requiring less skill to fit. Many
commercial mass-produced pieces are of poor
quality – but not all. The main concern for
such pieces is to look good from the outside;
long-term durability is not a major concern.
There follows a survey of the most commonly
extant materials and structures, however,
if a material was locally available,
economically viable and practical, it may have
been used in upholstery. Pine needles, thistledown,
leaves, bracken and chaff have all been
used but are less resilient and therefore less
likely to survive than more resilient materials
such as curled hair.
3.4.1 Fillings
Fillings may be loose, prepared, sprung, or
elastomeric (see Figure 3.9). Loose fillings are
supplied as an amorphous mass which requires
encasing between layers of other materials, for
example cloth stretched over the fill and
tacked to the frame. They may require to be
teased into position and stitched to take and
retain the desired shape. Prepared fillings have
already been given a form, either by machine
or by hand. They may consist of one or more
layers ready for use, requiring only to be cut
and attached to the frame. The selection of fillings
is guided by price, comfort and durability.
These in turn are influenced by factors such as
density, resilience, ease of use and the amount
of training required to use them properly.
The quality of filling is often judged and
graded by its resilience, that is, its ability to
recover its size and shape after deformation,
especially after compression. Loose fillings
require skill and judgement in handling and
are therefore expensive to use. Prepared fillings
have an economic advantage over loose
fillings in that they may be cut to size and less
skill is required to use the materials, both in
judging quantities and in applications.
A common characteristic of loose fillings is
that they are highly compressed for shipping
and transportation. Therefore, they require
opening out before use. This may be a manual
or mechanical process. Different terminology is
used for different grades of filling in different
countries and there is no agreed international
standard.
Animal materials
Curled hair is the highest quality filling as it
maintains good resilience over long periods.