The invention of Float Glass
In 1952 Alastair Pilkington was searching for ways to improve the quality of plate glass. It had always been a challenge to produce a consistent, undistorted product. It was a complex process that involved extensive rolling and polishing and significant costs and time. Many people wanted to make glass with the brilliant surfaces of sheet glass and the flat and parallel surfaces of polished plate.
There had to be a better way.
The moment of inspiration came when he was washing plates in a washing up bowl. The floating washing up liquid on the surface of the water was the inspiration for the development of a process that would change the manufacture of glass.
In 1959, seven years and seven million pounds after the ‘washing up bowl spark’ a commercial float glass process was born. In the process, a continuous ribbon of glass moves out of the melting furnace and floats along the surface of a bath of molten tin. The ribbon is held at a high enough temperature over a long enough time for the irregularities to melt and for the surfaces to become flat and parallel: because the surface of the molten tin is flat, the glass also becomes flat. The ribbon is then cooled down while still on the molten tin, until the surfaces are hard enough for it to be taken out of the bath without rollers marking the bottom surface: so a glass of uniform thickness and with bright, fire-polished surfaces is produced without the need for grinding and polishing.
The end product was a more economical, high class glass without the distortions that has enabled a new era of glass inspired construction. The stainless steel and glass structure, the Petronas Twin Towers in Kuala Lumpur, Malaysia, is 452 metres tall and contains 32,000 windows.
Glass made its first appearance in Mesopotamia, nearly 5000 years ago, in the form of pearls and jewels. The Egyptians also used it, from around 1500 BC. But it was the Romans who made the first glass windows, of a composition very close to that of present-day glass.
Most pre-Roman glassware was fashioned by the core technique, created using a mixture of clay and dung.
The original eyeglass first made an appearance in Northern Italy in 1269, although the true identity of who first invented spectacles will probably never be known.
Glass never wears out - it can be recycled forever. The energy saved from recycling one glass bottle can run a 100-watt light bulb for four hours.
Glass can help heal, repair and build bone and tissue. It is also used in the purification of DNA.
If every single glazed window in the UK was replaced with low emissivity double glazed units, the national CO2 savings would be nine million tonnes annually.