Centrifugal forming of glass

Centrifugal forming of glass uses a rotating mould to distribute hot glass outward. Norwegian technical descriptions also call the process sentrifugering av glass.

How the glass is formed

Glassblower Hanna Karlsen describes placing molten glass in the centre of an open metal or graphite mould. Rapid rotation then distributes the glass by centrifugal force. This differs from blowing, where air shapes a glass bubble, and pressing with a plunger. Rotation forms the object; it is not a subsequent grinding process.

Assessing an object

A circular bowl alone does not prove this method. Compare its form with manufacturer information, catalogues or documented workshop history. Do not assign a particular glassworks merely because an object appears mechanically formed. Describe scratches, rim chips and repairs separately from production characteristics. The technique specifies neither a particular glass composition, date nor automatic collector value.

Sources: Glassblåser Hanna Karlsen i Store norske leksikon: sentrifugering, pressing og blåsing.