If you've visited Chicago's Millennium Park, you probably noticed Cloud Gate, a sculpture nicknamed "the bean" for its familiar shape. It's hard to miss. Cloud Gate is more than 30 feet (9 meters) high and 60 feet (18 meters) long, coated in highly polished stainless steel plates. Inside is a massive steel frame assembled using arc welding. The sculpture's 168 stainless steel exterior plates were stitch welded (an arc welding technique) to the interior frame and polished to a mirror finish, creating a unique attraction for the Windy City.
Cloud Gate, a public sculpture by Indian-born British artist Anish Kapoor
Performance Structures, Inc. (PSI) was chosen to fabricate it because of their ability to produce nearly invisible welds
plates were welded together on-site, creating 2,442 linear feet (744 m) of welded seams. Welders used keyhole welding machines rather than traditional welding guns.[7] The plates were fabricated so precisely that no on-site cutting or filing was necessary when lifting and fitting them into position.[30]
Every weld on the Cloud Gate underwent a five-stage process, required to produce the sculpture's mirror-like finish.[30]
Removed welded seams
Shaped the weld contours
Smoothed the weld contours
Removed the fine scratches that were left from the Sculpting stage
Buffed and polished the surface to a mirror-like finish
The sculpture was finally completed on August 28, 2005, and officially unveiled on May 15, 2006.[38][39] The cost for the piece was first estimated at $6 million; this had escalated to $11.5 million
