Each spring, Doug Martenson stands eye-to-eye with Benjamin Franklin.
He cleans the buckles on Franklin’s shoes, the folds of his robes, and the buttons on his vest. Martenson then covers Franklin in protective wax.
Martenson takes about two weeks each spring—before the humid days and punishing summer sun—to clean and maintain Penn’s 19 bronze sculptures across campus. This annual maintenance cycle is a must to protect the iconic Franklin sculpture on College Green, William Pepper in the Perelman Quad, Pan With Sundial in front of the Van Pelt-Dietrich Library and others from sun, acidic rain, and normal wear-and-tear.
Martenson, a lecturer in drawing in PennDesign’s Fine Arts Department, has been working on the bronze sculptures since 1991, when the University began the process of restoring and maintaining the historic figures that adorn the campus landscape.
All of the bronze pieces were made around 1900, and until 1991, had not been maintained. In 90 years, copper inside the bronze had started to oxidize, turning the figures either bright green or black. “We came to these statues and they had deep, heavy green streaks on them, and other areas were quite black, and then in the recesses was the original patination,” explains Martenson.
In order to restore the bronze to their original splendor, he took walnut shells that had been ground up to a fine dust, blew it out on the sculptures at 60 pounds per square inch, and reduced the layer of corrosion, much like a gentle exfoliant removes debris from skin. That allowed Martenson to apply a layer of wax to protect the sculptures.
Each year since, he perches on a platform (much like a cherry picker to prune trees) to first clean the works of art, removing any debris with a PH-neutral detergent and water. The statue is then dried before Martenson heats up the bronze to about 177 degrees with a propane torch. Next, he applies a petroleum-based wax mixture that is absorbed by the bronze.
If he applies too much wax, it will bubble. If the bronze isn’t heated enough, the wax won’t settle into the sculpture.
“It’s got to have a consistent layer that will show the sculpture’s design and intent and not the surface that’s been damaged, which distracts you from seeing the whole form,” he says.
The sculpture is allowed to cool overnight (or for a couple of hours if it’s a cool day), before Martenson returns to buff it. A shiny, hard surface will more easily resist the elements, he says.
Martenson, a painter who studied at the Pennsylvania Academy of the Fine Arts, began working on bronze sculpture in 1985 with renowned conservator Virginia Naudé and her conservation group. Naudé was one of the first sculpture conservators in the area to start treating outdoor bronze. “What this satisfies in me is this need to do public works, because I really have that desire,” says Martenson. “I like the physicality of the work. I like the torches, I like the equipment. Each sculpture has its own personality, so you get to know that personality and track it.”
His favorites include the Franklin statue on College Green, sculpted by John J. Boyle in 1899, and R. Tait McKenzie’s 1914 statue, “Youthful Franklin,” which sits in front of Weightman Hall on 33rd Street. “It’s so animated, it’s so alive,” says Martenson of McKenzie’s work. “It looks like he’s ready to take another step.”
Once the annual work is completed, the sculptures are ready to face the summer heat and the start of the school year.
“If [the sculptures] were to be left, not only would they be unsightly, but the corrosion that builds up just starts rinsing away the sculpture, so eventually, there would be nothing left,” he says. “It’s incumbent on us to do what we can to try and save it for future generations. It’s an important thing.”
Originally published on June 6, 2013