WASHINGTON, DC.- The 76-foot-long mobile designed by Alexander Calder for the central court of the East Building of the National Gallery of Art will go back on view in early June after undergoing conservation treatment. Calder’s mobile is scheduled to be reinstalled on June 7 by National Gallery staff and engineers, including artist-engineer Paul Matisse (grandson of Henri Matisse).

Calder (1898-1976) created his first "mobiles" in the early 1930s. Using an ingenious system of weights and counterbalances, he eventually designed constructions that moved freely when suspended, powered only by slight air currents. The work he created for the East Building, Untitled (1976), is a prime example of this kind of construction. In 1972, when the East Building of the National Gallery was under construction, the artist was asked to create a large mobile that would complement the monumental atrium of the building.

Originally planned in steel, the sculpture would have been too heavy when enlarged to function as the artist intended. At Calder’s request, Paul Matisse transformed the design into an aluminum construction that retained the look and dynamism of the steel construction with a more employable weight. The sculpture was installed on November 18, 1977, one year after Calder died; it was his last major work of art. The monumental mobile is a feat of engineering, being lightweight, extremely strong, and capable of being moved by air currents. Weighing 920 pounds, it consists of thirteen panels and thirteen arms constructed of aluminum honeycomb and aluminum and steel bars.

In 1988, the mobile was removed from exhibition for conservation treatment for the first time. Since that refurbishment more than 15 years ago, the wearing of the mobile’s metal parts has slowly impeded its free rotation. The mobile was disassembled on April 19, 2004 in order to repair worn metal surfaces and clean and repaint its multicolored parts. The metal parts have now been repaired by welding and the addition of a hard facing coating of tungsten carbide with cobalt. As an additional preventive measure, steel liners have been fabricated and attached to a few of the contact points that had the most wear. Finally, the entire sculpture was repainted using the original color and paint formulation specified by Paul Matisse and the Calder Foundation. When it returns to its prominent perch in the East Building atrium, it will move and look once again as Calder had envisioned it.