A monochrome segment of glass cut from a trail.

An iron or steel tube, usually four to five feet long, for blowing glass. Blowpipes have a mouthpiece at one end and are usually fitted at the other end with a metal ring that helps to retain the gather.

(from French paraison) A gather, on the end of a blowpipe, that is already partly inflated.

(corruption of “grandfather”) The master craftsman in charge of a chair, or team, of hot-glass workers.

(1) The bench used by the gaffer while forming a glass object. Traditionally, this is a wide bench with arms, on which the gaffer rests the blowpipe with its parison of molten glass and rolls it backward and forward so that the parison retains its symmetrical shape during the forming process. (2) The team of glassworkers who assist a gaffer.

The process of pulling semimolten glass to elongate it. It is used, for example, in the production of canes.

A tool with two metal arms joined at one end by a spring. The distance between the arms is controlled by the glassworker, who uses jacks for a variety of purposes while shaping the parison (for example, to form the mouths of open vessels). This tool is also known as a borsella or pucellas.

A tool with two metal arms joined at one end by a spring. The distance between the arms is controlled by the glassworker, who uses jacks for a variety of purposes while shaping the parison (for example, to form the mouths of open vessels). This tool is also known as a borsella or pucellas.

A tool with two metal arms joined at one end by a spring. The distance between the arms is controlled by the glassworker, who uses jacks for a variety of purposes while shaping the parison (for example, to form the mouths of open vessels). This tool is also known as a borsella or pucellas.

Any instrument used by glassworkers to develop and shape an object. Glassworkers’ tools include the blowpipe, pontil, gathering iron, jacks, shears, clapper, pallet, block, pincers, battledore, lipper, and crimper.

(Noun) A mass of molten glass (sometimes called a gob) collected on the end of a blowpipe, pontil, or gathering iron; (verb) to collect molten glass on the end of a tool.

A tool used to trim excess hot glass from an object in the course of production. Many modern shears are embedded with chips of industrial diamonds.

The process of reheating a blank until it becomes soft and gradually flows under its own weight over or into a former mold and eventually assumes the shape of the mold. Soda-lime glass becomes soft at about 1110°F (600°C). Slumping is also known as sagging.

A glass cylinder intended to be cut into sheets.

The technique whereby glass is removed from the surface of an object by grinding it with rotating wheels made of stone, wood, and cork. The first stage of the process employs a stone wheel under a continuous stream of water. Later, wheels of fine-grained stone and wood, fed with various abrasives, are used to grind and polish the surface.

(1) The process of founding or melting the batch; (2) heating pieces of glass in a kiln or furnace until they bond (see Casting and Kiln forming); (3) heating enameled glasses until the enamel bonds with the surface of the object.

The technique of forming an object by inflating a gather or gob of molten glass on the end of a blowpipe. Traditionally and in modern furnace working, the gaffer blows through the tube, slightly inflating the gob, which is then manipulated into the required form by swinging it, rolling it on a marver, or shaping it with tools or in a mold. It is then inflated to the desired size. In flameworking, one end of the glass tube is heated and closed immediately, after which the worker blows into the other end and manipulates the hot glass.

(German, “gold between glass”) A type of decoration, produced in Bohemia and Austria in the 18th century, in which a design in gold or silver leaf is incorporated between two vessels that fit together precisely. Unlike Hellenistic and Roman gold glass, which is fused, Zwischengoldglas is bonded with cement.

The term applied to several types of Hellenistic and ancient Roman glass objects decorated with designs cut and/or engraved in gold leaf, which is sandwiched between two fused layers of glass. Hellenistic gold glass was made by sandwiching the decoration between two closely fitting cast, ground, and polished vessels, which were then fused. Many Roman gold glasses apparently were made by applying the gold leaf to the surface of an object, reheating it, and inflating a parison against the decorated surface.