When Mark di Suvero’s monumental, painted steel sculpture, Rumi (1991), was deinstalled in 2000 due to construction of the Museum's underground parking garage, it was discovered that the bottom of the base plate and the area behind the attachment bolts of the sculptural components were rusted.
In preparation for repainting the sculpture, the heavy layer of corrosion on the base plate was removed by sandblasting, while the lighter corrosion around the attachment holes was removed with a chemical peel. These bare areas were painted with a special zinc-based primer, the entire sculpture was covered with an epoxy-based paint and a polyurethane topcoat layer of orange paint was applied.
In order to eliminate the possibility of future rusting, a cathodic protection system was added to the base plate during its reinstallation. The system consists of 320 pounds of finely ground manganese metal in bags buried in the ground around the sculpture and connected to it with three electrical wires.
Natural moisture in the soil causes an electrical current to flow between the bagged manganese and the steel of the sculpture. As long as the electrical current flows between the two metals, the manganese will corrode, leaving the sculpture protected. When all of the existing manganese is used up (approximately 18 years), it will be replaced with new manganese, and the protective system will be renewed for another 18 years.
A grant from the Institute of Museum and Library Services helped fund the conservation of Rumi.