Dry Ice Blasting Restores Historic Union Terminal
Gentle Cleaning Removes the Grime but Leaves the Years Intact
Once a bustling Cincinnati train station that was filled to nearly five times its capacity during World War II as soldiers left and returned from deployment, the art deco Union Terminal in Cincinnati was deteriorating and desperately in need of restoration.
The iconic 1930s-era building was designed with a mammoth half-sphere rotunda, a tiered fountain that jetted water, gigantic glass mosaic murals and bands of gold on the ceiling, according to the National Trust for Historic Preservation. With the advent of automobile and plane travel, the station described as an “art deco palace that embodied American optimism at one of the country’s lowest economic points,” sat idle as crowds disappeared.
Following decades of decay, and years of planning and fundraising, a much-needed restoration was launched in 2016 with some of the top contractors in the nation. From architects to conservators, the project drew from a wide range of experts from across the country. The Polar Clean Team was among them.
Among the items that needed attention were hundreds of exterior aluminum window frames rising across the face of the rotunda entrance. There were more than 1,300 of them, etched by bird droppings, sun-faded and coated with decades of residue that included carbon from cigarette smoke and auto exhaust. The restoration company and a conservator hired to oversee the project wanted a cleaning process aggressive enough to remove the layers of grime, gentle enough to avoid the risk of collateral damage and precise enough to leave exactly the right amount of history in the patina.
Aluminum Window Frame: Before Dry Ice Blasting
Aluminum Window Frame: After Dry Ice Blasting
A Delicate Cleaning Job Calls for Dry Ice
It would have been an impossible task for nearly any other cleaning method, but it was an undertaking tailor-made for dry ice cleaning and Polar Clean processes.
Dry ice blasting, also known as CO2 cleaning, uses no water and can employ a wide variety of pellet sizes and varying amounts of pressure and was the ideal solution. With patented nozzle types and processes that allow for cleaning that employs a delicate “dusting” of fragile surfaces, Polar Clean’s dry ice cleaning left the windows grime-free, undamaged and with a finish that would not be out of place in 1932.
As the project went on, Polar Clean’s role was expanded to include cleaning of marble, terrazzo and terracotta tile throughout the terminal, as well as the brass fittings on an elaborate ornamental fountain.
In each case, dry ice cleaning made believers of project managers, contractors and restoration architects, many of whom knew little of its capabilities before seeing them firsthand.
All Aboard! The Many Advantages of Dry Ice Cleaning
The advantages of dry ice cleaning start at the finish: dramatically clean results that can restore a wide variety of surface material to its original glory. But along the way, there are savings of cost, time and clean-up that are very nearly as dramatic, if slightly less glamorous than the gleam on an iconic art deco train station.
Dry ice is fast, cost-effective, non-abrasive and mess free, eliminating the need for post-cleaning cleanup, repair or drying efforts. Dry ice pellets sublimate, or turn into a gas, on contact so the only cleanup required is the actual debris itself, which the Polar Clean team minimizes with carefully planned containment practices.
Dry Ice Produces a Superior Clean with a Delicate Touch
At Polar Clean, we have deep experience in the use of dry ice blasting for historic restoration, fire restoration and a wide variety of heavy industrial applications. Our processes have been honed over decades of collaboration with engineers, architects and university researchers.
Our expertise includes the cleaning of hard-to-reach spaces, like ceilings, narrow tubing and turbines, as well as best practices for the delicate work of restoration.
Getting the results exactly right for the Union Terminal project took a bit of artistry on top of our usual efforts, but the results were more than worth the effort.
“The results were beautiful,” said Polar Clean partner and COO Joseph Sergio. “Everybody was super happy.”