Outdoor Sculpture Conservation, Public Art Conservation, Architectural Features Conservation:
The Woodbourne Library in Centerville, Ohio just outside of Dayton has a unique architectural feature lining the south and west sides of the building: rows of painted boxes made from Cor-Ten, or weathering steel. The boxes are an artwork known as Sunscreen which is attributed to Harry Bertoia. It was likely installed in the 1960s, but there are limited records about the original artist and installation. Sunscreen is composed of 15 individual panels consisting of 10 by 10-inch open metal cubes which form a large screen structure. Some of the interiors of the cubes are painted while others have a brownish red passive corrosion layer. The pattern is random, and originally the colors varied between white, blue, and orange. In addition, some cubes are straight, while others are set at a forty-five degree angle. All cubes are titled downward, allowing rainwater to drain off the surface.
The building itself is currently under renovation providing a perfect opportunity to assess and treat the artwork. Years of exposure to the elements and lack of maintenance took a toll on the unusual piece. Only remnants of the original paint color remains, and the metal shows some signs of active corrosion. The paint had faded, chalked, and cleaved from corrosion undercutting. In 2017, the piece was assessed by NACE Certified Coatings Inspector, Emmett Lodge.
At this time, Lodge examined the dry film thickness (DFT) and adhesion of the previous paint film. He confirmed that despite the poor visual appearance of the sculpture, it was still in structurally stable condition. Lodge observed that a two-layer coating system was present, a colored top coat, likely an oil-based enamel paint, and a red primer layer. This red primer layer was tested for lead in multiple areas, an important step for future treatment and containment. Tests were negative for lead. Chips of the paint were also taken and color matched with standardized color charts. He determined that the most cost effective and safe treatment method for the artwork was to restore the weathering steel sculpture in-situ.
Emmett Lodge, Conservator of Objects Christina L. Simms, and Conservation Assistant Curtis McCartney all took part in this large scale weather steel treatment of the outdoor artwork. First, the original colors: blue, white, and orange were marked on the boxes. This information was critical to retain, since it was the only record available for the original color scheme. Next, areas of loose, flaking paint and corrosion were removed with power tools according to industry surface preparation standards. Areas to be painted were wiped clear of debris as needed.
An epoxy primer was applied before the paint colors; this provides a water impermeable barrier and better base for the top coating. Epoxy coatings, however, generally do not have the color retention and resistance to ultra-violet (UV) light like other paint systems. For this reason, a polyurethane top coat was then applied with rollers and brushes, ensuring that the coat was complete and even as possible. All work was completed by carefully working from either a lift or by ladder, especially in the tight area between the building and artwork.
The result of the conservation treatment of the weathering steel artwork reveals a renewed surface. Time spent carefully matching and mapping the color scheme is demonstrated in after treatment images. The weathering steel conservation was just a small part of a major renovation of the Woodbourne Library, which added a 10,000 square foot addition to the structure. Be sure to check out the newly renovated space, a good book, and Sunscreen on opening day.