Worldwide, 95 percent of flat glass is currently produced using the float glass process invented by Alastair Pilkington. The disadvantage of the production methods commonly used until then, such as rolling or mechanical drawing, is that the surface of the glass is affected. This resulted in time-consuming processing by means of grinding or polishing. To overcome this deficiency, Pilkington decided in the early 1950s to cast glass onto a tin bath in a controlled process. Due to its low specific gravity, the molten glass floats on the metal bath and is free to spread.
The idea for the process of using liquid tin as a carrier for the production of flat glass had already been conceived by Henry Bessemer in the middle of the 19th century. In 1902, William E. Heal was granted a U.S. patent on the manufacturing principle. However, this patent was never used commercially until Pilkington’s experiments. Although the principle by which float glass is produced seems simple, its implementation was immensely complicated.