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Float Glass Production Process

21 Mar 2011

In 1952 the process of glass production was revolutionised by Sir Alistair Pilkington when he developed a new method of creating glass that is referred to as float production. Imagined as an alternative to the expensive and time consuming polished plate glass process the float line is able to efficiently manufacture clear, tinted and coated glass for buildings, and clear and tinted glass for vehicles.

The process, originally able to make only 6mm thick glass, now makes it as thin as 0.4mm and as thick as 25mm. Molten glass, at approximately 1000ºC, is poured continuously from a furnace onto a shallow bath of molten tin. It floats on the tin, spreads out and forms a level surface. Thickness is controlled by the speed at which solidifying glass ribbon is drawn off from the bath. After annealing (controlled cooling) the glass emerges as a 'fire' polished product with virtually parallel surfaces.

A float plant, which operates non-stop for between 10-15 years, makes around 6000 kilometres of glass a year in thicknesses of 0.4 mm to 25 mm and in widths up to 3 metres. The float process has been licensed to more than 40 manufacturers in 30 countries. Around 370 float lines are in operation, under construction or planned worldwide with a combined output of about one million tonnes of glass a week.

Float Glass Raw Materials

These remarkable figures reveal the impact that Sir Pilkington’s invention has had on the modern world as it provided us with improved means to glaze our homes, cars and places of work along with providing glass for a variety of technical appliances that are now considered essential to our daily lives. Seeing the float line operating is an awe inspiring experience that illustrates how modern engineering feats like this have impacted the world around us. Also, as glass plays such an integral part in people’s lives you can be rest assured that float lines will be churning out glass to meet our needs for years to come.

Finished ribbon of float glass