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Jed Boal ReportingWhile lawmakers get back to work in temporary quarters next to the State Capitol, construction workers stream into the grand old rotunda to push ahead with restoration. One chilly innovation makes paint stripping a blast.
Coat after coat of paint and primer cover many surfaces in the Utah State Capitol. One way to blast it all off is dry ice.
Randell Heath, Coldsweep, Inc.: "All the dry ice disappears on impact, and doesn't leave any secondary waste."
The Director of the Capitol Preservation Board says workers strip steel, iron and decorative marble without damage.
David Hart, Architect of the Capitol: "We're able to remove the paint and primer and reveal all of the detail of the metal that was cast into it."
Carbon dioxide freezes at 109-degrees below zero, that's dry ice. When workers blast it, the dry ice goes through a process called sublimation. It turns from solid to gas and expands to eight hundred times its original volume.
Randell Heath, Coldsweep, Inc.: "It can get kind of under a nook or in a crack and can lift things off, where sandblasting is like taking an ice pick and pecking away at things."
Traditionally, workers would sandblast the surface or use a chemical stripper.
David Hart, Architect of the Capitol: "The sandblasting would damage the delicate detail in the beehive and the leaves and the medallions."
With chemicals, they'd have to take everything apart and take it off site to treat it.
Randell Heath: "Dry ice blasting is a good, environmentally sensitive cleaning method that they probably never dreamt of."
It's actually a rather simple solution to a complex problem. If they were to attempt to clean the surfaces with sandblasting, they would create a site that was not only messy, but also hazardous.
David Hart, Architect of the Capitol: "If we were sandblasting, we'd create a certain amount of breathable dust, which would be hazardous."
The dry ice blasters take safety precautions in a contained area, but simply sweep up the paint chips when the job is done.
When all surfaces are cleaned, painters will restore them with original colors. Unfortunately, the process is still too expensive to consider for home use.
