dk nkf - Nordisk Konservatorforbund Danmark

clockmaking restoration). These professionals with
knowledge of the most complex mechanisms seek to
restore the timepiece to working order in accordance
with traditional know-how [25]. For presentation to
the public, objects are restored to working order
and given a pleasing appearance. Plastics with
their poor mechanical strength easily fall victim to
clock and watch restorers, who very often decide
to replace damaged polymer parts. Their choices,
often opposed to those of conservators who prefer
to sacrifice the “use value” of an object if the repairs
called for are too extensive [26], [27], [28], risk
sacrificing a fundamental cultural dimension and an
essential part of an object’s authenticity. To evaluate
this risk, it is necessary to explore the patrimonial
value of plastics from all angles (technical, aesthetic,
historical, symbolic, economic, etc) because it is the
value given to a cultural object which “generally
decides how it will be conserved.” [29]. In the
context of conservation of an industrial heritage one
should thus measure the importance of historical
and ethnographic research to reveal the patrimonial
value of ignored objects or materials.
Plastics: a fundamental
heritage
Plastic is an essential material because it is eminently
representative of the watch and clockmaking
industry of the 20 th and 21 st centuries. According to
art historian Claude-Alain Kunzi, it is regrettable
that in the field of horology it is primarily the
scarcity of an object that determines its patrimonial
value and its place in a collection, eclipsing “the
concept of the pre-eminence of representativeness”
of the low-priced timepieces that form “part of
our history” [30]. In terms of representativeness,
historical research shows that plastics should have
a key place in collections because they have been
used since the 19 th century in clocks and since the
1960s have slowly been introduced into almost all
parts of timepieces [31], [32].
In fact, there are two phases involved in the
introduction of plastics [33], [34]. The first phase (1860
– early 1960s) corresponds to a discrete but significant
appearance of plastics in timepieces (fig. 4). According
to historians it is difficult to document precisely when
112
Figure 4. The Landeron 4750 electro-mechanical movement
(1960). The motor’s electric coil is overmoulded with plastic .
the first plastics appeared in timepieces from the end
of the 19 th century and there is very little information in
specialist literature. The oldest polymers were used for
isolating electrical parts of clocks. There is more precise
information from the 1930s about the use of polymethyl
methacrylate (PMMA) for glass replacement. Then,
in the 1940s-1950s, various plastics were tested for
making joints and circles, such as polyvinyl chloride
(PVC), acrylonitrile butadiene (ABS) or polyurethane
(PU). The second phase (1960s to the present) is
characterised by the increasingly visible use of plastics
in the watch and clock industry (fig. 5). The first watch
cases made of polymers were developed in the 1960s
Figure 5. The “Symbol” Watch, one of the numerous models of
the 1960s and 1970s. Except for the movement, the entire watch
is plastic 33x43mm.