United States Steel introduced Cor-ten steel for railway cars in the 1930s. By the 1960s and 1970s, sculptors including Louise Nevelson, Barnett Newman, Beverly Pepper, Richard Serra and Tony Smith took to this industrial alloy as a miracle material because of its formal character (Cor-ten’s other name is “weathering steel” and, over time, its surface exhibits a velvety rust-colored patina) and its tough durability (a boon for making large-scale outdoor public art works). Half a century later, prominent sculptors including Anthony Caro and Anish Kapoor are still using Cor-ten. However, some artists, conservators, curators, and public art guardians are wrestling with the material’s promise as they work to stave off unanticipated outdoor forces like water accumulation, acid rain, smog, humidity, and pollution from traffic while simultaneously trying to save major sculpture from being mothballed.
In a 2007 discussion with the J. Paul Getty Museum and the Getty Conservation Institute in in Los Angeles, Storm King Art Center director and chief curator David Collens noted that Cor-ten did not fulfill its initial assurances. “There are endless surprises with Cor-ten scultpures… the wonder material that did not turn out to be one,” said Collens. “They have problems of decaying on the inside, no matter what maintenance you do… It really is engineering. Bolts, welds, concrete foundations underground – a whole range of things that became far larger projects than originally anticipated.”
Case in point is Barnett Newman’s Broken Obelisk, 1963-67, a massive twenty-six foot tall sculpture in front of Houston’s Rothko Chapel. Challenges with the geometric structure of the Cor-ten as well as its placement over a reflecting pool have necessitated two rounds of conservation, the first between 1983 and 1984 and the second beginning in 2004. Broken Obelisk was re-installed in 2006. In documenting the restoration process, former Menil conservator Laramie Hickey-Friedman described how the metal had deteriorated so severely that conservators and a committee considered “the radical option of bringing the sculpture inside and possibly making an exhibition copy” for outdoor display.  Ultimately, this prospect was denied by the Barnett Newman Foundation.
Another key example of Cor-ten sculpture maintenance is Louise Nevelson’s Night Presence IV, 1972, a towering twenty-two foot tall public artwork located for four decades in the median strip at Park Avenue and 92nd Street in Manhattan. The artist donated the work to New York City and chose the installation site as a symbolic gateway between the Upper East Side and Harlem neighborhoods. After monitoring the piece for over a decade, “by 2007, it became apparent that adverse conditions of the Cor-ten steel were accelerating,” according to Jonathan Kuhn, Director of Art and Antiquities for the New York City Department of Parks and Recreation. In February of 2011, the sculpture was removed for restoration, and Kuhn anticipates that Nevelson’s work will be back in place by next year. This may be optimistic timing as the conservation team must first weather the sculpture off-site for up to one year to “allow the various elements to integrate (unify) visually” before its re-installation on Park Avenue, Kuhn emphasized.
Night Presence IV will have a facelift that, pragmatically, includes shoring up corroded sections with stainless steel so that the sculpture has a prolonged life. In consultation with Nevelson’s original fabricator, Lippincott, and sculpture conservators, segments of the work will be reinforced with “stainless steel internal framing, interior protective coating, and internal hidden cavities that will permit air to circulate and mitigate moisture entrapment,” Kuhn said. The City’s goal is to retain as much of the original Cor-ten as possible.
Nevelson’s first public work in her adopted city was based on a small sculpture of 1955 called Model for Night Presence IV in the collection of the Lowe Art Museum at the University of Miami in Coral Gables. The model is made of painted wood and measures just over two feet high. What was a tabletop sculpture of castoff wood fragments was transformed and magnified into magnificent architectural scale in the form of Night Presence IV.
Those who live near the site where the Cor-ten sculpture stood now witness an empty pad of turf and sidewalk with a sign directing inquiries to the Department of Parks and Recreation. At a recent gathering of neighbors to discuss the sculpture and to seek additional funds for restoring Nevelson’s work, the most urgent question asked of Parks Commissioner Adrian Benepe was “When do we get it back?”
 For an extensive report on the project of restoring Barnett Newman’s Broken Obelisk, see Laramie Hickey-Friedman, “Broken Obelisk: A Case Study,” The Getty Conservation Institute, Summer 2007. Retrieved from http://www.getty.edu/conservation
Featured Image: Louise Nevelson, Night Presence IV, 1972.