Glassmaking has been a part of American life for more than 400 years. Like other products with a long history of use, manufacturing techniques have changed over time. However, the usefulness of glass will never go out of style.

Early Days

Organized glass production in what would later become the United States began in the early 1600s in Jamestown, part of the colony of Virginia. However, for several reasons, these initial manufacturing efforts did not last long. More than a century later, relatively large glass factories started opening further north in the colonies of New York and New Jersey.

In the middle of the 1700s, a tax on glass led to the production of thinner, more delicate products, including stemware. Still, prior to the American Revolution, the colonies still got much of their glassware from Europe. Changes in manufacturing techniques led to the development of clearer glass. In addition, in the early 1800s, glass-pressing machines began to appear.

Window and Sheet Glass Production

For a long time, the available options for window glass were limited to fairly small panes. In the 1800s, one of the most popular products was crown glass, which varies in thickness from its edges to its center. U.S. factories also produced a form of window glass called blown plate, which required more intensive manufacturing processes than crown glass, and therefore cost more money.

Until the 1900s, the manufacturing of sheet glass was a relatively complex process. This fact limited the availability of high-quality window glass. However, things changed in 1902 with the invention of the sheet glass drawing machine. This machine allowed manufacturers to automate the glassmaking process and produce sheets as large as 10 ft. in length. The arrival of sheet glass drawing heralded the beginning of large-scale window glass output in America.

Float Glass

Window glass manufacturing truly entered the modern age in 1959 with the invention of float glass production. In this method of production, molten glass is poured onto a base of molten metal, then gradually cooled. There are two benefits to this technique. First, it makes it possible to reliably create sheets of glass in precise thicknesses. In addition, the float glass process makes it possible to produce sheets with extremely flat surfaces.

Float glass was actually invented in the United Kingdom by a man named Alistair Pilkington. However, American manufacturers quickly adopted the technique and put it into use on a large scale. Today, roughly 90 percent of all the world’s flat glass is still made through the Pilkington float glass process.

Color and Patterns

Colored and patterned drinking glasses entered mass production in the early 1900s. By the 1920s-1930s, the American market was shared by seven large-scale manufacturers. Together, these companies made products available in roughly ten colors, including blue, pink, black, yellow and crystal. In addition, their products were available in almost 100 different patterns.

Surviving Manufacturers

Today, two of America’s oldest glassmaking companies still survive: Corning and Blenko Glass Company. Corning first opened for business more than 165 years ago. In addition to sheet glass, its current product line includes ceramics and advanced optics for a range of commercial and industrial applications. Blenko opened its doors in the 1890s. In modern times, the company specializes in drinking glassware and various types of architectural glass.