Cloud Gate aka the ‘Bean’

The Cloud Gate sculpture by Indian-born British artist Anish Kapoor, lovingly referred to as ‘The Bean’, is the centerpiece of AT&T Plaza at Millennium Park. At 66 feet long, 33 feet high, 42 feet wide and weighing in at 110 tons (yes – 220,000 lbs!) the sculpture is comprised of 168 stainless steel plates welded together and polished to a seamless mirror finish.

MB Realty Company, who manages Millennium Park for the city of Chicago, is charged with maintenance of the sculpture as well as the rest of the park.

The Challenge

As a highly-visited tourist destination, service has to be scheduled in ‘off-hours’ to allow public access. The sculpture is cleaned and polished during off-peak months while the park is closed, generally between 11pm and 6am.

Anyone who’s worked to keep stainless steel appliances fingerprint-free can appreciate the monumental task of maintaining the metallic luster of Cloud Gate. The 66 ft. long, 33 ft. high, 42 ft. wide piece is continuously exposed to the elements and combined with the resident pigeon population, regular cleaning and polishing is a necessity.

Maintenance crews wipe down the bottom six-feet of the three-story sculpture several times a day with soft polishing cloths, but what about the rest of it?

How does the ‘Bean’ keep that high shine all year long?

The Solution

The crew sets up a lightweight aluminum scaffolding around the ‘Bean’ after 11 p.m. and works until about 5:30 a.m., removing the scaffolding until the next evening.

Next, a mild detergent and low-pressure sprayer is used to remove dirt and bird droppings. Then the crew hand polishes the steel with an environmentally friendly solution to achieve that mirrored look.

The Benefits

Day-to-day activities of the park were not affected.

All events continued as planned.

The project was completed safely and efficiently.