An artist catching molten lava inside the University foundry.
Marriage of iron and fire: Minnesota Iron Pour turns 35
Minnesota Iron Pour turns 35
By Pauline Oo
Published on April 29, 2004
The first thing that strikes you--if you're new to an iron pour--is the smell in the air. It will either be burning coke in the cupola or melting chemical binders in the sand molds. The second thing you'll notice is the hodgepodge of protective helmets and leather in constant motion. On April 23, the annual Minnesota Iron Pour took place inside and outside the University's foundry on the Twin Cities campus. The 35-year-old tradition, sponsored by the Department of Art and the College of Liberal Arts, saw students and artists making more than 100 iron cast sculptures for class and independent study or research. "It went pretty good," says Wayne Potratz, University sculpture professor. "Everybody's sculpture got poured, we had a lot of visiting artists from out of town, and it was over a little faster than usual because we were producing more metal per hour with two machines." About 2,400 pounds of donated radiator iron was broken down into smaller pieces and 300 pounds were fed every 20 minutes or so into two cupolas, which are cylinder-shaped steel furnaces with heat-resistant linings that melt iron with heat from burning coal. While Potratz oversaw the feeding and heating of the larger cupola housed inside, his teaching assistant Allen Peterson reigned in the courtyard. "What I enjoyed most about the pour was being able to teach one of my students [who is building his very own furnace as an independent study project] how to run the furnace," says Peterson, a University graduate student who's been pouring iron since 1995. The University's cupolas do not run on common coal, but a purified coal called coke. "We use that because it burns cleaner and hotter than regular coal," explains Peterson. "Coke's been used ever since the industrial revolution. There are coking plants that burn out everything from coal except for the carbon. So what's left is close to 100 percent carbon." Peterson and Potratz managed teams of people who rotated jobs during the four-hour event. Feeding the cupola was only one of many tasks at hand. When the burning coke reaches the right temperature, the cupola's drain is plugged and iron is added. The metal, which can heat to beyond 2,400 degrees Fahrenheit, is given time to melt before the drain is unclogged with a tapper or blunt metal rod and molten iron is poured into a bucket. Its contents are then emptied into molds made of sand and a chemical-binding mixture. "It's a rhythm," says Potratz, a 35-year cast iron veteran. "As soon as the iron comes out, you have to pour it because it starts to cool down. It's kind of like a dance that happens on a choreographed basis." And the dance that Friday was called Feiticeiros de Ferro e Fogo. Potratz and Peterson came up with this Brazilian theme, which means "Sorcerers of iron and fire" simply as a tribute to a culture they both admire. "We just sort of asked the question, 'If the University Sculpture foundry had a parade in a Brazilian Carnival what would our theme be?'" recalls Peterson, who has family in Brazil. "Although we didn't have any Brazilian artists participating, we thought that carnival energy was appropriate to the 35th annual because [reaching five-year marks] are always cause for more celebration."