Glass Making Techniques

How was glass made in ancient times?

Core-formed glass

The earliest glass vessels were made by forming a core of sand, mud, or clay around a metal rod (hence the alternate term “rod-formed” glass). The core was dipped in or covered with strands of molten glass. Handles and bases could then be attached and the core removed.

Core-Formed Glass Video by the Getty Museum

​Blown

A mass (“gob”) of molten glass is attached to a hollow tube and then inflated by blowing through the tube. The object can then be transferred to a solid metal rod to be further decorated and shaped. Th technique probably arose in Syria-Palestine.

Ancient Glassmaking Video by the Art Institute of Chicago.

Mold-Blown

Molten glass is blown into a mold to form a vessel and its decoration simultaneously.

Mold-Blown Glass Video by the Getty Museum

Millefiori (mosaic)

Varicolored rods (“canes”) of glass are fused together and sliced. The slices are arranged in a mold and heated to form a vessel.

Mosaic Glass Video by the Getty Museum

Splash-decorated

Small fragments of multicolored glass are sprinkled onto a partially blown vessel and stretched out by further inflating the vessel.

Threaded

Streams of molten glass are wound or trailed over the body of a hot vessel.

Tooled

Hot glass is shaped with tools.

Other interesting videos

Ennion and His Legacy:

Mold-Blown Glass from Ancient Rome –

Corning Museum of Glass Lecture

Engaging Roman Glass by Harvard Museum of the Ancient Near East

Conservation of a Roman Glass Bottle by Toledo Museum of Art