The conservation and restoration of clocks refers to the care given to the physical and functional aspects of time measuring devices featuring "moving hands on a dial face" exclusive of watches. Care for clocks constitutes regulating the external environment, cleaning, winding, lubrication, pest-management, and repairing or replacing mechanical and aesthetic components to preserve or achieve the desired state as specified by the owner. Clocks are typically composed of multiple types of materials such as wood, metal, paint, plastic, etc., which have unique behaviors and environmental interactions, making treatment options complex. The materials used and the complexity of clockwork warrant having a Horological Conservator complete the work.
Conservation and restoration Interventive actions can be taken by trained conservators when clock issues arise, with treatment varying depending on the type of clock and situation.
Horological conservation history The history of clock conservation dates back to ancient times. Horology, the study of the measurement of time, dates to 1450 BC, "when the Ancient Egyptians first observed the earth's natural circadian rhythms (Meadows, C., (n.d.).Meadows, C., (n.d.). Horology: A Brief History. Retrieved from: https://www.artsandcollections.com/article/horology-a-brief-history" Some examples of instruments used to measure time include: clocks, watches, sundials, hourglasses, time recorders, and atomic clocks. Horological Conservation is the science and art of preserving timepieces to connect humanity with the history and heritage of timepieces. Conservators
A conservator who specializes in clock care will have the qualifications and training to properly treat a clock with the wherewithal to "[...] not totally compromise the historical worth of the object [...]." Conservators rely on a system of examination, documentation, and research prior to treatment so that proper treatment is received, as "Sometimes the only way one can understand the detailed history, quirks, and specific eccentricities common to a particular timepiece is by studying it to glean as much information from it as possible [...]." Aside from pinpointing clock issues and providing care to a clock in need, conservators are also able to impart knowledge about procedures like clock winding to ill-informed clock owners so that future clock damage due to human error may be avoided.
Conservators are encouraged to use restraint when restoring objects due to ethical concerns and only make necessary repairs rather than altering the appearance of objects such as clocks for aesthetic preferences. One exception to this dilemma is conservation done to correct previous treatments, which scholarship and investigation have proven to be dishonest or poorly-conceived efforts that took an object further away from its original form.
Preventive conservation Preventive conservation involves the proper handling, creating and maintaining suitable storage and display environments, and regular maintenance to prevent issues from arising and impacting a clock's sustainability. Such controls can extend the life of a clock.
Correct handling
Handling is a potentially a major source of damage to any heritage item. Any handling of an object should be planned in advance and requires some precautions. Certain measures taken by a clock handler can prevent opportunities for damage.
Work areas should be clean and arranged to support the safety of the clock: uncluttered, free of any potential for the clock to be bumped, jostled, or moved unnecessarily, and secure from theft.
Wearing "[...] cotton or Nitrile gloves when handling the metal portions of the clock" can limit opportunities for transfer of contaminants from hands to clock surfaces.
Loose items such as jewelry and loose clothing like scarves or bulky jackets worn by a handler have the potential to come into contact with, and cause damage to, a clock. Removal of these items prior to clock handling can lower the risk of damage.
Pendulum damage during clock movement can be prevented by either removing the pendulum or fixing it within the interior of the clock via a latch or padding prior to clock movement. This can also prevent damage to other interior components.
When moving or handling a "weight-driven clocks, it is advisable to wait until the clock has wound down before it is relocated. Once it has stopped running, carefully remove the weights and pendulum".
A clock "[...] should always be grasped at its most sturdy area" and moved from one location to the next on its back.
The correlation of the size of a clock with the number of people moving it can ensure the safety of the clock. A small, mantle clock for example may only require one mover, while a tall clock can necessitate a number of movers to safely carry it to another location.
Proper storage and display
Proper storage and display mechanisms can work to ensure a clock's safety. For safety and mechanical reasons, conservators securely fix long case clocks and wall clocks to a wall to avoid accidents and to ensure the clocks area to run properly. The use of a solid, sturdy surface when storing or displaying a clock can prevent it from falling on a hard surface. A wall clock for example requires a secure attachment "[...] to a wall if accidents are to be avoided and clocks are to run properly." Clock cases, which come in many different materials, require special consideration and treatment in their own right. Conservators further advise not exposing a clock to a heat source of any kind, including strong sunlight or a mantel over a working fire, as this can cause damage to the clock cases and movements.
Motion sensitive lighting and use of non-direct light sources can limit the amount of light and heat withstood by a clock, both of which are sources of clock damage. A clean clock environment can eliminate opportunities for dangerous contaminants to come into contact with a clock. An HVAC system can add an extra level of security by removing such contaminants from the air.
Correct humidity and temperature levels The humidity and temperature of the environment in which a clock is being displayed or stored can adversely affect the clock's condition. Damage may be avoided by maintaining certain levels of humidity and temperature within the clock environment, dependent on the materials from which the clock is constructed. a. Wood clocks The ideal humidity and temperature ranges for clocks whose cases are made from wood vary depending on the season. In the summer, an environment with a temperature of 70 to 75 degrees Fahrenheit and 40% to 60% relative humidity is suitable. During the winter, an environment with a temperature of 70 degrees Fahrenheit and 35% to 50% relative humidity is prime.
b. Metal clocks Clocks whose cases are made from metal function well in an environment with a temperature of 68 degrees Fahrenheit and a relative humidity of 30%.
Running clocks vs. static display Clocks can be simple display objects if they are not required to run. This reduces the physical force on the clock. Whereas "running any functional object will result in wear and handling, which contributes to the degradation of the parts. Replacing the inner workings of a clock still requires handling, which could potentially damage the clock. Conserving a non-functional clock is much less invasive (cheaper!) and preventive protection against corrosion and environmental hazards is the main concern for its stabilization and care.[viii] Perhaps the least invasive solution to highlight a functional clock would be to purchase a replica clock and safely store the original". Running clocks also require winding, which adds to the wear-and-tear of the gears and leads to more handling of the object.
Regular clock maintenance Regular maintenance of a clock can ensure its long-term preservation. Conservation experts advise clocks need to be serviced regularly. A clock is a complex mechanical contraption made of a variety of materials and with many small moving parts.Historical Clocks, 2012. Retrieved from: http://publish.illinois.edu/cuhistoricalclocks/preservation/ Even under perfect conditions lubricants deteriorate. Clocks should be examined and re-lubricated every three years. After five years, and certainly no longer than eight years, the whole movement is advised to be dismantled and 'cleaned' if excessive wear and expensive attention is to be avoided
Visual inspection can determine whether a clock should be cleaned and/or lubricated, whether any signs of infestation and/or damage exist, and whether a clock should be wound and/or set to the correct time.
Regular maintenance also applies to the environment surrounding the clock to ensure that the correct storage conditions are present.
Cleaning, polishing, and lubrication Regular clock surface dusting can negate opportunities for corrosion or abrasion as a result of dust buildup. It should be stated that such surface cleaning can also result in a loss of information about a clock's history, as "[...] various "dirt" or "salt" deposits can provide precious clues to an objects past [...]." Loss of clock function due to clockwork wear can be avoided through regular clockwork cleaning, polishing, and lubrication performed by a trained professional. In performing such maintenance, a professional will disassemble clockwork so that it can be thoroughly examined "[...] for worn or broken parts, fatigued springs and accumulations of dirt or oil."
Cleaning clocks consist of multiple steps, which may or may not all be done as part of a treatment plan: washing, ultrasonics, rinsing, drying, polishing, refinishing, chalk brushing, and pegging out. At this point, should cleaning be the only treatment employed, the pieces could be reassembled with proper lubrication; however, depending on the type of clock, the pieces could also be primed for further treatments to the various parts such as mechanisms, frames, wheelwork, pivots, mainsprings, screws and screw threads, escapements, balance springs, pendulums, etc.
Winding and setting In order to function as time keepers, and to prevent damage to clockwork, clocks must be regularly wound. An established winding schedule eliminates the threat of over-winding."Traditionally, the job of winding the clocks was given to an horologist or a trained individual. Winding had to be done at certain times of the day; ideally when the temperature was just right and the room vacant. Each clock had its own unique keys, doors, and intricacies within the mechanisms." Regular winding can also ensure that clockwork is still functioning. In setting the correct time, the minute hand is turned clockwise to the desired time.
When hand setting a clock, manually moving the hour or seconds hand rather than the minute hand to set the time can be damaging, as can be counterclockwise hand turning. Moving the minute hand ahead on a clock by several hours when setting the time can also lead to clockwork damage. For this reason, "Rather than turning the hands forward through several hours it is better to stop the clock and re-start it when the time matches that on the dial."
Agents of deterioration
Damage can occur via a variety of mechanisms, either rooted in human error or naturally caused. Agents of Deterioration (AOD) are the ten primary categories of threats to heritage objects. These agents of deterioration can occur while an object is in storage, on display, undergoing conservation, or during handling or transportation of the object.
Physical force
Physical force is any impact, shock, vibration, pressure or abrasion that causes damage to an object. Physical force damage commonly occurs when handling the object. Any excessive physical force will break, damage, splinter the clock frame or easily shatter the glass of the object.