Plate Glass

Plate glass, also known as flat glass or sheet glass, is a type of glass that is typically used for windows, glass doors, fascades, and windscreens. Flat glass can also be bent after production of the plane sheet for modern architectural and automotive applications.

Why is it Called Plate Glass?

The first method of producing flat glass was to pour molten glass onto metal tables or “plates” and roll it flat before cooling. This method produced the plates of glass that are known as plate glass – hence the reason for it’s name (plate glass).

History of Plate Glass

In modern times, the vast majority of plate glass is produced using the float process which was invented by Sir Alastair Pilkington in 1952. However, many other methods used to provide flat glass throughout history including –

Broad sheet method (13th century) – Invented in Germany, this method used molten glass poured onto a cast with water on top to produce large sheets of flat glass.

Window crown glass technique (14th century) – Hand blown glass method that created a flat glass pane with a characteristic “bullseye” in the middle

Blown plate method (17th century) – A labor intensive method which involves hand grinding broad sheet glass to create

Plate polishing (17th century) – Polished plate glass is a type of hand-made glass which is produced by casting glass onto a table and then grinding and polishing the glass.

Cylinder blown sheet method – Glass is blown into a cylindrical iron mould in this manufacturing technique. The ends of the cylinder are removed, and a cut is made down the side. The cut cylinder is then rolled into a flat glass sheet in an oven.

Machine drawn cylinder sheet method (early 20th century) – The earliest mechanical method for “drawing” window glass was machine drawn cylinder sheet. Glass cylinders 40 feet (12 metres) tall are extracted vertically from a circular tank. After that, the glass is annealed and cut into 7 to 10 foot (2 to 3 m) cylinders. They are then cut lengthways, reheated, then flattened.

Rolling (rolled plate glass, figure rolled glass) (19th century) – Molten glass is poured onto a metal plate and flattened with rollers. As it allowed for the production of large flat sheets of glass, it was the preferred manufacturing technique for architectural glass such as those used in large windows and shopfronts.

Is Float Glass the Same as Plate Glass?

Plate glass was previously made by grinding large “plates” or ribbons of rough formed glass until they were clear before the invention of the float process. As a result, all plate glass can be considered as float glass but not all float glass can be considered as plate glass. Check out this article to learn more about float glass.