Manual glass production until 1900 covers the traditional methods of making flat glass by glassblowing, without machines. Window glass was entirely handwork until the end of the 19th century. The glassblower gathered molten glass on the blowpipe and shaped it into a pane using breath, tools and great craftsmanship.
Application
Two main methods existed. In the crown glass process, the glassblower blew a sphere, opened it at one end and, by spinning it rapidly, let it flare out into a flat, circular disc. A thick lump remained in the centre, known as the bull’s-eye or crown. Small panes were cut from such a disc.
In the cylinder or muff glass process, the maker blew a long cylinder, cut it open lengthwise, removed the ends and unrolled the glass in the furnace into a flat sheet. This method produced larger sheets than crown glass.
Characteristics
The limitations were clear: panes stayed small, the surface showed bumps, waves and air bubbles, and the thickness was uneven. Large windows were therefore built up from many small panes held in a framework of glazing bars or lead. Bull’s-eye panes were deliberately used as decoration.
Related terms
- glass
- building glass
- wired glass
- leaded glass
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