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Caring for Bronze in the Community

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Jul 21 2010

This summer I am fortunate to have two dedicated and hard-working interns working with me to help take care of the IMA’s many outdoor sculptures.  Here is a post by Jessica Ford and Katherine Langdon discussing their experiences treating the Sewall Memorial Torches which are on loan to Herron High School. Katherine and Jessica take their work very seriously and are pursuing careers in conservation.

Historic photograph of Sewall Memorial Torches

“Hey, I have a new project for you guys,” Richard greeted us as we came into the conservation lab one morning. “The museum owns a pair of bronze lampposts that have just been loaned to Herron High School and installed at their original location at 16th and Deleware. The school is really excited to have them back. Since they are IMA property, we are responsible for taking care of them. That’ll be our job, so start researching bronze. Chop, chop!”

Thus began our first adventure into the world of outdoor bronze treatment and our blossoming knowledge of the subject. Our research fell into two categories: the history of the Sewall torches themselves, and the characteristics and treatment of outdoor bronze sculpture.

Bronze is one of the oldest and most important materials in human history. Its strength, beauty and other characteristics make it well suited to industrial, military, and artistic uses, giving it such prominence in the archaeological record that it lends its name to an entire stage of human technological and social development (the Bronze Age!) .  Check out the bottom of this post for more information about bronze!

The Sewall Memorial Torches are intimately tied to the history of the Indianapolis Museum of Art and the arts movement in Indianapolis at the turn of the 20th century. As the savvy blog reader will remember, May Wright Sewall was the founder of the Art Association of Indianapolis. Shortly after her death in 1920 the Association honored her contributions to society by erecting these torches outside what was then the Herron Art Institute, the city’s first art museum and art school (the school is now located on the campus of IUPUI).

When the museum component moved to the present location in 1970 and became the IMA, the torches came with.  They remained in storage (indoors and out) until this year, when they were returned to their original location.

Armed with this knowledge, the three of us boldly set out for Herron High. There we began our first official documentation project of the summer.

Conservation is full of documentation, and we had to learn how to do it the right way. Materials needed: camera, tape measure, pencil, and paper (and a good eye). We examined the torches, their installation, stability, and overall appearance, and then wrote a condition report complete with a thorough description and pictures of their pre-treatment state.

Conservation Treatment Report

The first thing confirmed was that the torches are structurally stable—the installation was excellent; new mounts were bolted into the limestone, not directly attached to the torches but merely holding them in place underneath. All evidence of the torches’ original patina bronze is now lost from decades of exposure to the natural elements.

Exposed surfaces showed the bright green of verdigris, and the sheltered areas were a crusty black. This splotchy appearance made the overall shape of the lampposts and the designs within the intricate bronze-work difficult to fully appreciate.

Sewall Memorial Torch before treatment

We decided that the best treatment short of a complete restoration of the patina would have two stages: 1) cleaning off the lose corrosion on the surface, and 2) coating the entire surface with a thin layer of wax, which would unify the appearance of the bronze by saturating the light green corrosion layer.  The wax would also protect the bronze from further weathering and graffiti.

Once we developed a satisfactory treatment plan, we gathered our materials. First, the white van, a monstrosity big enough to haul around the three of us and all of our necessary items, including:

  1. Ladders—these torches are tall, standing 10.5 feet on their own, and mounted on limestone bases about 3 feet tall.
  2. Power washer.
  3. Propane tanks, torches, and lighters.
  4. Brushes.
  5. Wax.
  6. Traffic cones.
  7. Various tools.
  8. Sunscreen!

Upon arriving at the scene of the assignment, we drove directly onto the sidewalk and scattered the contents of the van around to broadcast our official purpose.  A group of Herron summer school students stared on curiously while eating their lunch as we began taking turns blasting the torches with gallon upon gallon of high pressure water.

Katherine Langdon power washing

It was a hot day, but we didn’t feel it. Within five minutes we were soaked from head to toe from the water ricocheting off the bronze. This went on for hours. Even half-blinded by the force of the water in our faces, we could see patches of darker bronze emerging from beneath the verdigris. Finally the first torch was clean, revealing a much healthier surface.

Jessica Ford power washing

Richard meanwhile attended to many important cell phone calls and internet searches on his iPhone, which never seems to leave his side.

After the water we progressed to fire.

Hot wax treatments are ideal for outdoor sculptures because the wax used has a very high melting point and hardens into a rigid coat that lasts fairly well through the effects of the changing seasons. Richard formulated the wax compound we used on the torches earlier in the year.  The microcrystalline blend consists of 80% Microwax W-445, 17% Bareco 2000, and 3% Cosmolloid 80 H.

Application of hot wax requires the bronze to be heated with a propane blow torch, which makes the wax fluid upon contact and allows for a smooth and even coating.

Katherine and Jessica hot waxing

Swapping tasks between heating the bronze and spreading the wax, we began the arduous process of coating the lampposts. The wax had the immediately satisfying effect of unifying the color of the surface into a rich, dark greenish-brown. We vertically challenged interns took responsibility for the intricate crevices and detail-work on the lower portion of the torches, and Richard used his height advantage to coat the upper reaches.

Katherine showing the torch waxed half way

In detailed areas we also used Trewax, a commercially available paste wax (applied cold) made mostly of carnauba wax.

Richard applying Trewax

And so it was that after days of work, a little bit of sunburn, and a lot of learning that we brought the Sewall Memorial Torches to their more dignified current state. Their appearance now more closely reflects the originally intended aesthetic, allowing visitors and passersby to enjoy their design.

As we packed up to go, one of the first passersby to see our finished work was an elderly man taking a stroll with the aid of a cane. He stopped to admire the torches and then addressed us with an excited smile. “I’m so glad these lampposts are back. You know, I used to be a student here when it was still the Art Institute, and I was sad to see them go. I always loved these lampposts. I’m so happy they’re back!”

Whoa. That was the moment we realized that we’d done more than just re-wax some old bronze. We had helped return a fondly remembered piece of history to the Old Northside. As the former posh stomping grounds of a U.S. President and the blighted scene of countless crimes and drug deals, the neighborhood has seen multiple transformations since the torches were first installed, some for better, some for worse.  Another recent addition to the neighborhood is Indiana Landmarks, whose new headquarters is in the former Central Avenue Methodist Episcopal Church, which is currently under major restoration.

The lampposts recall the most valuable contributions of the neighborhood during one of its most successful moments; back in their place of prominence, they are now symbols of the restoration of the community.

Sewall Memorial Torches after treatment

After we packed all of our supplies back into the van, we drove straight to Dairy Queen for a much-needed reward. We decided to enjoy our treats while taking the scenic route back to the IMA through the neighboring Crown Hill Cemetery.  Richard pointed out the many different bronze, limestone, and marble monuments that quietly reveal the development of Indianapolis. One of these is the elegantly heartbreaking homage to Albertina Allen Forrest created at the turn of the 20th century. It features a bronze figure of a young woman in mourning made by Rudolph Schwartz, the same artist who sculpted the roundels on the front façade of Herron High School (next time you’re there, look up).

These objects, their relationship to their time, and their role in the progression of our city are history lessons worth preserving. Now we are equipped to assist in these efforts.

Finally, for those of you who like factoids, here are a few interesting ones we learned about bronze during our research:

  • Bronze is an alloy usually containing 88% copper, 12% tin.
  • It is used in sculptures for these reasons:
    • it is a hard but relatively non-brittle metal alloy;
    • it protects itself from damage to a certain extent by forming a surface layer of corrosion that seals and protects the rest of the bronze — this is called the patina;
    • it sets in detailed molds particularly well.
    • The final surface appearance of bronze is up to the maker, who controls the patina via various complicated chemical processes. For example, the surface can be patinated to appear black, brown, dark gold, green and many other colors. It can even be patterned.
    • The earliest surviving bronze artifacts date to the late 4th millennium BC.
    • When bronze corrodes outdoors, the most frequent results are:
      • verdigris, the sea-foam colored powdery corrosion often seen on copper roofs, fountains, and other untreated copper-based alloy pieces. (Verdigris is also frequently used as a decorative patina.)
      • black corrosion (copper-sulfur compounds) that builds up as a result of air pollution and gathers on parts of the bronze that are sheltered from rainfall.

Filed under: Conservation, Guest Bloggers, Local

This entry was posted on Wednesday, July 21st, 2010 at 8:50 am and is filed under Conservation, Guest Bloggers, Local. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

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