Updated 10:45 p.m. Friday.
URBANA — The Alma Mater may need more extensive surgery than originally thought.
And that familiar blue-green patina? Turns out it's not the original color but corrosion that is eating away at the surface, experts say.
Tests show that hundreds of iron bolts on the interior of the University of Illinois' signature sculpture have corroded or disintegrated, indicating serious structural problems, conservator Andrzej Dajnowski said Friday.
"This is much beyond what was expected," said Dajnowski, owner and director of Conservation of Sculpture and Objects Studio Inc. of Forest Park.
The sculpture still could return to campus before commencement in May, but it depends on how the university decides to approach the project, he said. The Alma Mater, originally cast in 30 pieces, might have to be taken apart to be fully repaired, he said.
The campus Preservation Working Group, which is overseeing the project, plans to meet with Dajnowski to discuss the options over the next few weeks.
The restoration is being funded by gifts to the UI through the Chancellor's Fund. The original cost was projected at $100,000, and it's too soon to say whether the budget will have to be increased, said Christa Deacy-Quinn, collections manager at the Spurlock Museum and a member of the Campus Preservation Working Group.
She said the working group needs more information from Dajnowski about the repairs needed and the potential cost before making any decisions. The X-rays were just completed Tuesday, she noted.
Dajnowski briefed donors on the project at the annual meeting of the University of Illinois Foundation.
Deacy-Quinn and others had noticed signs of corrosion on the Lorado Taft sculpture back in 2009, and the working group decided to take on the restoration project.
The 10,000-pound sculpture was removed from its base at Green and Wright streets in early August and shipped to Dajnowski's studio for restoration.
When it was first lifted, Dajnowski noticed that the lower bolts were mostly stainless steel and in good shape. Then the sculpture was raised up further, and pieces of corroded bolts started falling off, he said.
Further inspection showed that all of the bolts above the knees of the three figures — Alma, Learning and Labor — were the original iron bolts and had corroded. Chemical analyses and X-rays showed the extent of the damage, including the presence of damaging chlorides, he said.
Some bolts are missing pieces; others are stuck in place; and some have disappeared. The back of Learning has no bolts holding it together, he said.
Dajnowski estimated that 300 to 500 bolts will have to be replaced on each of the three figures, plus the chair, which was too big to be X-rayed.
"We know there is a major problem," he said.
He said sculptors in the 1920s usually used bronze bolts, but this is the second Taft sculpture he has seen with iron ones. For some reason, the foundry that Taft used must not have understood it was "creating a big problem."
The lower bolts were replaced during repairs made in 1981 by sculpture Professor Robert Youngman, but he couldn't get inside the sculpture to reach the upper bolts, Dajnowski said.
Some of the seams in the sculpture also were caulked to keep water out, but that inadvertently sealed moisture inside, causing more problems, Dajnowski said.
Deacy-Quinn said her team had hoped the project would mostly involve surface repairs.
"I never expected this extent of work," she said Friday.
Chemical analysis also showed evidence of graffiti, including above Alma's eye and in her sleeve.
And the blue-green hue so familiar to generations of students? Corrosion that's "eating the surface," Dajnowski said.
He said he took samples from inside the crevices of the sculpture to try to find its original color, but they included many signs of corrosion, too.
Deacy-Quinn said campus officials haven't decided on a final color. The only thing they know, she said, is that the blue-green is "actually a corrosion product that was dangerous to the sculpture."
Once a decision is made, the studio will apply a protective wax coating that can last three to five years, Dajnowski said.