What materials did Alexander Calder use for his large outdoor stabiles?

Alexander Calder’s large outdoor stabiles are primarily constructed from sheet metal. These monumental works consist of flat, curvilinear metal shapes that are either welded or riveted together.123

Typically painted in solid colors, most often red or black, these sculptures are designed to be stationary, contrasting with his famous mobiles that move with air currents. While Calder utilized a variety of other materials throughout his career—such as wood, bronze, wire, and found objects—his large-scale public stabiles are defined by their substantial sheet metal construction.123