In December 2006, 27 mega-steel columns were arc-welded together to anchor New York's Freedom Tower at the former site of the World Trade Center. Each column stands more than five stories tall and weighs as much as 30 tons.
In 1962 DuPont patented the explosion welding process, which it used to produce the clad metals needed by the U.S. Mint for new coins. In the next three years DuPont make over 70 million pounds of dime, quarter and half-dollar blanks.
The U.S. Navy recently set a world record by completing a west weld at 2,000 feet below the surface. The job: to train for deep sea submarine rescue.
Today GM employs more than 20,000 robot welders. But in 1961 there was only one: Unimate, the first industrial robot in history. Unimate performed spot welds by following step by step command stored on a magnetic drum.
Narrator: It arcs, explodes and blisters steel. It's used to make 50% of all products and it puts the power to build a skyscraper in a man's hands. By friction or robot, even underwater, these are the tools the world can't live without. Now: Welding, on Modern Marvels.