GLASSMAKING

HOW IS GLASS MADE?

What evidence do we have for glassmaking in the UK?

Historic England's Archaeological Evidence for Glassworking provides an overview of the types of glass used in Britain from the Bronze Age to the early 20th century, and how the raw materials, processes and products changed over time.

How sheet glass is made

Crown glass is mouth-blown glass blown and spun into a disc – it often has curves from the centrifugal force of spinning while blowing down the blowpipe. It was the most common method of making glass until 19th century (and used in medieval period).

Cylinder glass is mouth-blown glass blown into a cylinder and then scored and opened up into a sheet. It was a new way of making sheet glass from the 19th century and still used today.
[bold:
Cathedral glass] is textured on one side and produced by rolling molten glass on a metal plate. It is often used for plain windows and the trade name ‘Cathedral’ is a little misleading. It can be made in different colours and textures. It is a modern invention (from 1830s).

How is glass coloured?

Glass is coloured by the addition of metallic oxides to the molten glass mix. For example, cobalt produces blue glass, gold produces a red-pink, and manganese a purple colour.