Ian McMahon, Tether, 2018. Plaster and steel hardware, 65 x 25 ft. Photo: Clements Photography and Design, Boston, Courtesy the artist

“Sculpting with Air”

Lincoln, Massachusetts

deCordova Sculpture Park and Museum

Ian McMahon and Jong Oh are both interested in shaping the intangible, though their work, and processes, couldn’t be more different. Brought together for “Sculpting with Air” (on view through September 30), they also introduced a new experience for deCordova visitors, who were invited to watch the progress of their site-specific installations.

McMahon, because of the size and complexity of his works, has to plan everything down to the last detail. Engineering and computer modeling are essential for him. His process (much simplified) goes something like this: first he blows up big plastic forms, then he sprays a plaster coating inside, lets it harden, peels off the plastic, and voila—a rigid form that looks soft and balloonish. Of course it’s more complicated than that—the inter-connected balloons are big enough to walk into, and they have to be airtight. Inside, the plastic is supported by a wooden armature; where the forms come together, McMahon builds a wooden doorway, sealing the joints between units with plywood lath. He inflates them during the plaster-spraying phase with powerful air compressors, and he has to construct a double-doored airlock to enter into his construction. He builds the whole thing in his studio first. Besides being a plasterer, he is a carpenter, materials specialist, metalworker, designer, mechanic, and computer geek. A video shows the spectacular destruction of earlier McMahon works—columnar forms smashed by one swing of a long pipe. Tether will also be destroyed at the end of its run, but viewers won’t get to see it happen.

In contrast to this massive work, Oh produces delicate, challenging lines in the air. Because his installations depend on optical illusion, he has to see and think about the spaces they are to occupy before he knows what he wants to do. Here, he worked in two adjacent small galleries. The first appears to be an empty room. As eyes and brain focus, forms, lines, and boxes begin to emerge. One horizontal seems to pierce the wall and continue into the next room. For the verticals, Oh uses extremely fine chain, sometimes with a brass plumb bob on the end so it will hang perfectly straight. He makes the horizontals with fine-diameter rod; fishing line contributes but remains invisible. Oh’s works demand that we concentrate and truly see.

Though McMahon and Oh couldn’t be more unlike, they are both illusionists. McMahon’s work, an engineer’s dream, looks like it’s full of squishy stuff, but it isn’t. Oh’s geometries convince us there is a form hovering in space—and there isn’t. His works are subtle and intellectual, a thinker’s art. Pairing these two artists was curatorial genius, an inspired way to get us thinking about the seen and unseen, about how air shapes the world as we know it.

—Marty Carlock