16. Conserving Mechanical Elements in Technological Artifacts: Three Case Studies from Museo Nazionale della Scienza e della Tecnologia “Leonardo da Vinci,” Milan
- Marianna Cappellina
- Claudio Giorgione
Abstract
Developing a single protocol for the preservation of kinetic artifacts in technical and scientific museums can be challenging. Many factors need to be taken into consideration, such as the number of identical technical and scientific artifacts produced and displayed in other collections, their productive processes, and whether they are serial or handcrafted as unique pieces. The museum also needs to address essential issues such as long-term storage of artifacts, perishable machines, whether or not to display objects with parts in motion, and how an exhibit can help visitors understand the movement of a machine.
Technical and scientific museums are involved daily with the issue of preserving objects with moving parts. A display of moving machines provides an immersive experience for the visitor, but it can generate risks to the objects’ materials and components. Unlike unique works created by an artist with aesthetic intentions, technical and scientific machines were developed for practical purposes and often have a productive function. They can also be handcrafted, as in the case of scientific instruments, models, or replicas. For this reason, the development of a single preservation strategy can be difficult. The case studies below illustrate some of the challenges routinely faced by the museum.
Cockcroft-Walton Generator
First designed in 1932, the Cockcroft–Walton generator is an electric circuit that produces a high voltage from a low voltage. A system of capacitors and diodes generates this voltage, along with kinetic components such as dynamos (fig. 16.1), which are housed inside rounded aluminum casings. The machine is assembled over two Bakelite isolating cylinders. The electrical components were lost during the first installation in the museum in the 1960s; furthermore, safety concerns prevent us from activating the machine. It was decided not to reintegrate the electrical functionality but to potentially keep the dynamo system moving. The conservation treatment was realized in January–June 2016 by Strati s.n.c.
40-Horsepower Cassani Tractor
The Cassani 40 is an important diesel tractor first produced in 1927. It underwent conservation treatment, performed by Strati s.n.c., in February–April 2015 for display in a permanent exhibition gallery about nutrition. The artifact involves two kinds of movement: the ignition of the diesel engine, and the kinematic motion of the wheels and gears. The movement of its wheels, including the steering wheel, was used to place it inside the gallery. The engine remained turned off for safety reasons and, during conservation, all the diesel tanks were drained.
Nineteenth-Century Jacquard Loom
There were many discussions about the conservation of this complex Jacquard loom, which was originally used to create textiles with complicated patterns such as brocades. The first idea was to return it to working order by replacing many of its parts, such as ropes and dobbies. However, 1,200 silk warp threads out of the beam were destroyed and detached from the finished fabric. The installation of a new warp would have been very difficult and expensive. A simpler and more sustainable conservative restoration was chosen, with a static presentation. Only the broken ropes have been replaced; the damaged section of warp threads was cut and placed as near as possible to the finished fabric. The conservation treatment was realized by Giuseppe Pellegrini in June–September 2015.
