Page "Stained glass" Paragraph 14

Architectural glass must be at least 1 / 8 of an inch to survive the push and pull of typical wind load.

In order to make red glass, the ingredients used must be of a certain concentration, or the color won ’ t develop, but the resulting color is so concentrated, that if a sheet were made that is 1 / 8 ” thick, little light could actually pass through it – it would look black.

So another method is usually used for making red glass, where most of the body of the glass is clear or a colored tint.

This lightly colored molten gather is dipped into a pot of molten red glass, forming a laminate that is then blown into a sheet of glass using either the cylinder ( muff ) or the crown technique as described above.

Once the solution was found for making red glass, other colors were also made this way.

A great advantage is that the double-layered glass can be engraved or abraded to reveal the clear or tinted glass below.

The method allows rich detailing and patterns to be achieved without needing to add more lead-lines, giving artists greater freedom in their designs.

A number of artists have embraced the possibilities flashed glass gives them.

For instance, 16th century heraldic windows relied heavily on a variety of flashed colors for their intricate crests and creatures.

In the medieval period the glass was “ abraded ” ( ground off ), later hydrofluoric acid was used to remove the flash in a chemical reaction ( a very dangerous technique ) and in the 19th century sandblasting started to be used.