Traditional glass is an integral part of the overall
aesthetic and character of historic buildings, but is often maligned for its
perceived imperfections. Luckily, traditional glass is being preserved and
protected more and more; allowing it to be enjoyed for years to come.
So how do you know if you have historic glass in your property? We take a look at the top five different varieties of traditional glass and how you can identify it in your own home.
1. Cynlinder Glass
Cylinder glass was constructed by blowing a cynlinder of molten glass, which was then cut at the ends and along the side before being flattened out in a furnace. It is also known as “broad”, “sheet” or “muff” glass and was popular until the mid 1700s.
Cylinder glass can be indentified by its slightly rippled surface (which the ripples generally running in the same direction). This is usually accompanied by a pattern of long air bubbles that lie in straight, parallel lines.
2. Crown Glass
Crown glass is made by blowing and then spinning molten glass into a large thin disc knows as a table. This large thing disc would then be cut into smaller panes. Crown glass is often slightly curved with distinctive semi-circular lines known as the ream. It is thinner, brighter and shinier than cylinder glass. It tends to have a visible pattern of concentric circles, and may hav a small thick circle of glass or “bullseye” from the centre of the table.
3. Plate Glass
To make early plate glass, thick cylinder glass or cast glass was ground down to make it flat and then the surface polished until smooth. Plate glass was very expensive as a result of this labour-intensive process. So it was used, from the late 1600s onwards, mainly for mirrors and to glaze high status buildings.
4. Patent plate glass
James Chance invented the process for making ‘patent plate’ glass in 1839. This process made it possible to grind and polish thinner sheets of glass than the traditional plate glass technique allowed. Manufacturers could then make more finished glass from the same quantity of raw materials.
5. Drawn flat sheet
Glass production became more mechanised from the early 1900s. Various methods were invented to allow a continuous sheet of glass to be drawn out of a furnace of molten glass. Each sheet was passed through a series of rollers and cooled, and then mechanically ground and polished.
You can find out more information on historic buildings, including traditional glass, at the Engine Shed.
Cocoon Window Insulation is a trading style of Glaze and Save Ltd