Mural Art Casting: A Step-By-Step Look.

The creation of this red brass mural overcame several production obstacles with the right mix of talent and creativity.

Just as industrial castings go through several phases before they are produced and passed on to customers, art castings undergo their fair share of planning. With commissioning, sketches, sculpting, molding, casting, welding, patinas and curators to deal with, the development of an art casting not only takes time but requires a great deal of cooperation among those involved.

This statement especially rings true with the creation of the "City of Modem Explorers" mural casting. Tracing the life of this 2-year project, this article details the evolution, from conceptualization to unveiling, and the obstacles that had to be overcome in order to produce this remarkable art casting.

The Conception

The casting's beginnings can be traced back to a 1997 centennial celebration for Dow Chemical Co., a main source of employment for Midland, Michigan, a city of 50,000. A subcommittee of the Midland Foundation, a volunteer service that conducts local non-profit projects, was given the task of memorializing this momentous event but could not decide what to do.

In May 1998, the committee decided to create a park that memorialized not only Dow's 100 years in Midland but the city's growth as well. The park, which would be located at the intersection of Jerome and Main Street on land donated by Midland citizens, would be a welcome addition to the city, represent the historical relationship between Dow and Midland, and commemorate the city's past and hopes for the future.

Later that year, the Foundation met with Joel Straus, president, Joel Straus Consulting, Chicago. After discussing a "hodgepodge" of philosophic ideas, Straus introduced the idea of a park that combined both landscaping design and sculptures. In their search for qualified artists, the team contacted more than 200 landscape architects and galleries, narrowing their choices to three. The team of sculptor Neil Goodman and Peter Lindsay Schaudt Landscape Architecture, Inc., Chicago, was chosen to design the park.

At the same time, the 55-year-old Midland Circle Theater, which had been modified as a bowling alley during its annals and scheduled to be torn down in November 1998, was undergoing a demolition inspection. Amidst the search, workers came upon an 11 x 24-ft plaster mural hidden above an acoustical drop ceiling in the theater's foyer. The mural, which had been hidden for more than 40 years, was sculpted by Corrado Joseph Parducci in 1942 as a decoration for the theater. Its subject matter--the agrarian, riparian and industrial history of Midland, its patriotic elements and the statue of its artist--mirrored the paintings found in the foyer of the Midland County Courthouse constructed 18 years earlier. Both artistic examples seek to chronicle, as a seamless evolution, the history of Midland from its native American roots on the banks of the Tittabawassee River to its massive industrial growth as the home of Dow. The mural's title, "Midland: The City of Modern Explorers," is emphasized by the inclusion of the f igures of Thomas Edison and Henry Ford, holding, respectively, a light bulb and a mechanical gear.

The bas-relief (two-dimensional) mural was salvaged and donated to the Midland Historical Society, which funded its removal and reinstallation. Upon discovering the piece, the Foundation and Straus knew right away that it would make an ideal centerpiece for the park.

Production Begins

Due to plaster's poor performance in outdoor conditions, the Foundation presented Straus with the idea of producing the relief as a bronze casting, to which he was in full agreement.

In June 1999, the first step in producing the bronze mural was creating a mold from the plaster relief. Dow Corning used this opportunity to test a new thixotropic silicone material that could be sprayed onto a vertical or upside-down surface. The result was a successful eight-piece silicone mold of the relief. Dow believed this would serve as a proper pattern for tooling for the art casting, so it was shipped to Wagner Brass Foundry, Inc., a 16-employee green sand and investment casting shop in Chicago. This foundry, which accounts 90% of its production to art casting, was chosen to cast the relief based on its previous work for Goodman and its ability to meet cost demands.

To create the new tooling, the foundry contacted Michael Re, a sculptor in nearby Roselle, Illinois, who had previously constructed molds for the foundry, including those for the Harry Caray statue outside of Chicago's Wrigley Field.

In August 1999, Re worked in Wagner's plant for 2 weeks. He filled the eight silicone molds, each 7 sq ft, with Forton MG, a modified gypsum, or architectural outdoor material, used to produce facades. This fiberglass-reinforced hydrocal, consisting of powdered resins and hardener, bonds on a molecular level with a liquid polymer rather than being activated by water. This provided added flexural strength to the molds to ensure that they would not break under pressure.

After setting the open-faced molds in a horizontal position, Re prepared 60-lb batches of the gypsum, adding polymer to activate it. He also used an accelerator (an aluminum sulfate) to speed up the activation while keeping the material in a manipulative state. After pouring the mix through a strainer to eliminate debris, Re applied the first coat by brush to the inside of the molds, making sure not to leave any entrapped areas where bubbles could form.

In the next batch, Re added chopped strands of fiberglass to increase the material's strength exponentially, then applied the slurry by hand. Spreading and padding the mix in a thin layer, he ensured a good contact between the first and second coat and paid close attention to the smoothness of the back of the mold, avoiding undercuts.

When situating the eight hardened patterns on the floor, it was discovered that they did not fit together and no longer created a seamless, unified piece. The varying thicknesses and planes of the patterns came as a result of some breakage of the mural when it was cut into eight sections for the silicone molds.

After nearly scrapping the project, Wagner weighed its options for casting the relief. Investment casting would require extensive welding and reconstruction while sand casting would require new, refinished patterns. With the current patterns unable to produce a finished bronze casting, Wagner decided to have Re reassemble the relief with the damaged sections, restoring the imperfections caused by the original molds. By eliminating the production of new molds, this method not only would save a step in the process but a considerable amount of money as well.

In the Right Hands

Re transported the eight patterns to a garage in Naperville, Illinois, where he built a 15 x 30-ft wood wall on which he mounted and leveled the gypsum relief to work on both its front and back. To combine the eight sections by their seams, he applied fiberglass from the back of the relief and the gypsum mix to the front, followed by grinding, pneumatic sanding and hand sanding.

In order to adjust the levels of the sections, 0.5-in threaded-rod pegs were drilled into each of their four corners, ensuring a seamless, balanced casting that would later mount on a perfectly flat surface. As the relief neared its completion, Re moved and increased the number of pegs to more than 60. These pegs were covered with the gypsum mix so that Wagner could pull them out without damaging the piece.

With several detailed areas of the mural's surface lost, Re filled the gaps and touched up the broken components and parts where needed. Using only a couple of photos of the original, it was a daunting task to undertake. "I got a feel for Parducci's style," said Re. "After working with the piece for a while, I was able to mirror his approach to different situations. I had to invent here and there but not too much."

Careful Casting

Following a successful inspection by representatives from Midland and Dow, Re and Wagner President Rick Wagner decided on the best places to cut the relief into sections so that they weren't too heavy for cranes or too large for the foundry's flasks. Using a reciprocating saw with the thinnest blade he could find, Re carefully cut the piece into 15 sections and brought them to the foundry in January.

More familiar with casting smaller sculptures, plaques and nameplates, Wagner handled the relief with extra care and attention. Before creating the molds, workers ground the plaster, making it thinner in specific areas. This practice allows for more efficient casting and welding. When ramming the green sand molds, workers made sure the edges were matched up perfectly. Because of the large pockets and deep returns, it was essential that the patterns were well-bedded in sand. Re's exceptional work on cutting the sections played a big role in producing these seamless molds.

"When this casting is assembled, it will be our largest job ever," said Wagner. "We're used to working with smaller castings, so we treated the sections like a series of large plaques. The only difference is that the scale is much larger."

At a pace of 1 per day, each section required a 400-lb red brass pour from Wagner's induction furnace. In order to maintain the exactness of the seams, each section's gates were carefully cleaned and ground.

In March, the sections were sent to the Midland park where a 1-ft-th1ck concrete wall was waiting to display the relief. In order to hoist the sections, cranes were used, and for support, stainless steel angles were strategically placed (depending on weight distribution and area thickness of the mural) both on the wall and the backs of the sections. After the levels of the sections were checked, Luke Grimm, a contractor from Chicago, spent 1.5 weeks blend-welding them together.

Next, Wagner employees sandblasted the relief, eliminating fingerprints, oils and welding residue. A medium-warm patina then was applied by Wagner. Patina refers to the color of the metal surface caused by oxidation, weathering or chemical treatment. This application also acts as a protective coating, and the warmer the patina, the longer it will last. To bring out a more natural bronze coloring and to highlight certain sections of the mural, such as the individuals' faces, steel wool was applied to these areas.

The final steps were lacquering and waxing the surface, which will protect it and prevent it from turning green over time due to inclement weather.

The end result is a stunning 6000-lb 10 x 25-ft casting (4 ft from the ground) that beautifully reflects Parducci's original relief, which now is featured at the Midland Center for the Arts.

The Unveiling

On May 12, at a well-attended celebration, the mural was unveiled to Dow management, major funders and the Midland community in the Dow Centennial Garden of Ned S. Asbury Park. The relief is set off in the 120x240-ft garden in its own "amphitheater" among beautifully handcrafted landscapes and other sculptures.