Perpetual Conservation: a Continuing Collaboration to Conserve Jack Nelson’s Kinetic Sculpture Clock

Nicole Flam, Laura Kubick, and Kristin Cheronis

Abstract

Jack Nelson was an artist and educator who was part of the Experimental Studios in the College of Art at Syracuse University in New York. Although he was known primarily for his kinetic sculptural assemblages, as a teacher Nelson inspired a generation of multi-media artists including celebrated time-based media artist Bill Viola, to whom he served as an advisor. 

Jack Nelson’s Minneapolis Sculpture Clock was fabricated in 1967, and installed in 1968 on Nicollet Mall, Minneapolis’ downtown pedestrian shopping street. An early example of integrated public art, the Sculpture Clock is the last remaining element of the respected historic design from the 1960s Mall, created by visionary landscape architect, Lawrence Halprin in an effort to keep downtown vibrant in the era of burgeoning suburban shopping malls.

From the start, this timepiece and artwork was engaging and distinctive, quickly becoming a well-known and beloved landmark. It is both a street clock, with 4 large dials in the upper cabinets of the case; and it is also a kinetic sculpture, or as the artist called it, a “Perpetual Motion Stabile.” A 16’ glass and steel case encloses a complex grouping of more than 830 copper alloy moving parts. After installation, the kinetic sculpture ran for 34 years, receiving minimal maintenance and occasional minor repairs and modifications by city workers to keep it running. However, by 2002, only the clock elements were still working. The kinetic artwork had ground to a halt. The motors were beyond repair; the metal was heavily tarnished; and there were many missing and broken elements.

A large-scale renovation of Nicollet Mall began in 2015. In preparation, the City of Minneapolis conducted research within the community about the existing collection of public art on the mall. The results showed that Minneapolitans felt the Sculpture Clock contributed to the community, provided continuity with the Mall’s past, and was the work of art that the public most hoped would return after the redesign.

Between 2015 and 2017, KCI Conservation undertook the complex, collaborative conservation treatment of Jack Nelson’s perpetual motion sculpture and clock. A team was assembled consisting of KCI conservators and interns, clock experts, metal artists and fabricators, electricians, engineers, and Minneapolis’ public art administrators. After discovering a remarkable trove of historic documentation, KCI was able to repair and restore the intricate kinetic sculpture, replacing motors and re-creating missing elements, re-engineering hidden functional components for longevity, as well as repairing and returning the clock case and clock dials to their intended appearances.

Since the full conservation treatment, KCI continues to work with members of the treatment team to carry out regular inspections and maintenance on the Sculpture Clock, thanks to an ongoing commitment to its upkeep by the City of Minneapolis and the Minneapolis Downtown Improvement District. In 2024, the clock received another conservation treatment after an incident of vandalism which shattered the glass on one of the case doors. This paper explores the history, treatment, and continuing work it has taken to conserve this extraordinary example of public art.

2025 | Minneapolis | Volume 32