Glasswork Glossary

Abrasion-The technique of grinding shallow decoration with a wheel or some other device.

Acid Etching-The process of etching the surface of glass with hydrofluoric acid.

Annealing – After glass has been worked with heat, it will have residual stress within from temperature differences. Annealing is the process of heating the glass very slowly to a set temperature determined by the make and type of glass. It is held at this heat for a soaking period, during which the glass relaxes all stress, but does not change shape, or slump. It is then cooled very slowly to room temperature.

Applied Decoration-Heated glass elements (such as canes and trails) applied during manufacture to a glass object that is still hot, and either left in relief or marvered until they are flush with the surface.

C.O.E. – Stands for “coefficient of expansion” which is a measure of how much a material expands for each degree it is heated, expressed as 104 x 10-7/0C. The whole number value is generally used by itself when comparing different types of glass, such as COE 104 for Moretti, and COE 90 for Bullseye.

Calliper - Tongs that help create and control the molten glass piece.

Cane – Glass rod or cane, is produced by slowly and steadily drawing a piece of glass from a molten pot of raw glass, or by heating and drawing out a block of glass that can have complex patterns inside. The cane is cut to lengths, or in slices, for use in glassblowing.

Cane - A cross section of glass made by pulling and stretching molten glass from both ends. Several colour pattern and designs can be created. Whatever design is used along with the detail will continue to hold the precise shape, scale all the way down to an invisible dimension.

Casing – Covering the entire surface of the work with glass, using clear glass on beads, and generally a neutral colour on mosaic work.

Chill Mark- An area on a hot worked glass piece, that has become slightly cracked on the surface because of being over-exposed to steel.

Cold Work - Using grinding wheels, wet sanders, a diamond drills, U/V Glues… to shape, flatten or polish glass at normal temperatures.

Coloured Glass - Glass that is coloured by (1) impurities in the basic ingredients in the batch or (2) techniques of colouring glass by one of three main processes: (a) using a dissolved metallic oxide to impart a colour throughout, (b) forming a dispersion of some substance in a colloidal state, and (c) suspending particles of pigments to form opaque colours.

Core - The form to which molten glass is applied to make a core-formed vessel. In pre-Roman times, the core is thought to have been made of animal dung mixed with clay.

Decoration - A technique whereby a hot parison is rolled in chips of glass, which are picked up, marvered, and inflated.

Didymium - Protective eyewear worn by glass artists have pink lenses to help cut down on the UV rays emitted by the furnace and gloryhole

Drawn glass beads – In the manufacture of glass beads, drawn canes with a central hole are produced the raw material from which many nearly identical beads will be cut. They can be produced in great numbers in a short time, compared to wound glass beads which must be made one at a time. The cut pieces of cane are finished by flame polishing, or by tumbling with abrasives.

Embossed - Raised or lowered text or design on any surface of glass.

Eye beads – Beads made of any material that have circular or spotted decoration may be considered eye beads. They were considered to ward off evil, by always watching out for the owner.

Faience - A fired silica body containing small amounts of alkali and varying greatly in hardness depending on the degree of sintering. It is covered with glaze, which may also be present interstitially among the quartz grains within the body. The term “glassy faience” is often used to describe a faience in which the reactions have proceeded to such an extent that the glass phase defines the visual appearance of the material.

Feathering - Dragging a thread across a hot piece of glass thus creating a decorative effect

Filigrana – A clear cased glass rod with a coloured core.

Flameworking - Using a tabletop torch and cold canes & tubes of glass to make a variety of glass objects

Flashing- The application of a very thin layer of glass of one colour over a layer of contrasting colour. This is achieved by dipping a gather of hot glass into a crucible containing hot glass of the second colour.

Frit – Granulated coloured class, sometimes referred to as crumb glass. Hot glass is rolled in frit to create the effect of small dots of colour. A single colour can be used at a time, or mixed colours applied to form a pattern of spots.

Fusing – Fusing is the joining of glass while in its molten state. It is what happens to each gather of glass added to the piece being worked, a fundamental step in all glassblowing. It also is used to describe work done in a kiln or an oven where the pieces of glass are allowed to fuse together while hot.

Gathering – Another fundamental step in glassblowing, molten glass must be accumulated in the proper amount and location, referred to as gathering. The glass rod when heated in the flame will form a “gather” at the tip as it is rotated and softens.

Gilding - The process of decorating glass using gold leaf, gold paint, or gold dust. The gilding can be applied with size or amalgamated with mercury. It is then usually attached to the glass by heat. Gold leaf can be picked up on a gather of hot glass.

Hand Press - A tool shaped like a pair of pliers, with flat jaws containing molds. Hand presses were used extensively in Europe for making chandelier parts. Later, they were introduced in the United States for pressing stoppers and bases.

Hard Glass - A generic name for glass (e.g., borosilicate glass) with a relatively low coefficient of expansion. Soft glass (e.g., soda-lime glass), by contrast, has a relatively high coefficient of expansion.

Hot-Worked - The generic term for glass that is manipulated while it is hot.

Hothead Torch- The Hot Head torch is not as hot as an oxy/fuel torch, but you can still make soft-glass beads, marbles, and small sculptural pieces.

Kiln - An oven used to process a substance by burning, drying, or heating. In contemporary glass working, kilns are used to fuse enamel and for kiln-forming processes such as slumping.

Lampwork – A form of glassblowing where the glass is heated over a flame. Originally from the Middle Ages, the term lampwork referred to oil lamps with a blowpipe directed into the flame to increase the heat generated. Today, modern torches use propane, natural gas, or hydrogen mixed with compressed air or pure oxygen to generate the intense heat required.

Latticino – The twisted canes of multi coloured glass, cased in clear, are called latticino. In the basic design, the coloured glass will look like a flat ribbon twirling inside the clear glass but may also be many thin strips of colour which spiral lengthwise.

Mandrel - In glass working, a metal rod around which beads, and other small objects can be formed.

Marvering – To shape heated glass into a cylinder, it is rolled over a flat marble, stone, or cast-iron surface called a “marver”, and the process is called marvering. Most bead makers today use a graphite plate or handheld paddle.

Moretti – A brand of soft glass from Italy, that comes in many colours both transparent and opaque that is generally compatible for fusing together.

Murini - Glass tiles and round tiles that are fused together in glass coloration designs, usually they are quite intricate.

Punty – A temporary handle attached to the glass piece in work where a “cold touch” of glass to glass to glass will break off easily when the piece is finished.

Sand - The most common form of silica used in making glass. It is collected from the seashore or, preferably, from deposits that have fewer impurities. For most present-day glassmaking, sand must have a low iron content. Before being used in a batch, it is thoroughly washed, heated to remove carbonaceous matter, and screened to obtain uniformly small grains.

Soda - Sodium carbonate. Soda (or alternatively potash) is commonly used as the alkali ingredient of glass. It serves as a flux to reduce the fusion point of the silica when the batch is melted.

Sodium Flare - The bright light that is given from the reaction of oxygen rich flame and the sodium of the glass in a kiln. Didymium glass in the glasses to avoid serious damage to the vision of one’s eyes. Usually, Flame-workers Lamp-workers are at the primary concern here.

Soft Glass – (soda lime glass) Glass is composed of quartz sand (silica, silicon dioxide, SiO2) soda (sodium carbonate Na2CO3 or sodium oxide Na2O) quicklime (calcium oxide CaO) and other oxides added for clarity or colouring. The glass used in most of our beads is a soft glass, referring to the relatively low temperature that it is worked and how fluid it gets. The soda acts to lower the melting point of silica and was originally produced from the ashes of seaweed and certain salt water tolerant plants. Lime is added to strengthen the glass. In some areas potash (potassium carbonate K2CO3) was substituted for soda which is produced from wood ash. Historically, glass produced in factories varied depending on the local materials available.

Stringer – Glass rod of perhaps 2 mm or less diameter, that is used to add detailed decoration.

Threading - The process of winding a thin trail of glass around an object to create the appearance of parallel lines. In 1876, W. J. Hodgetts of Stourbridge, England, patented a machine that produced very regular and closely spaced threads.

Tweezers - To be used to pinch and pull glass.

Twist - A type of decoration in the stems of 18th-century and later drinking glasses, made by twisting a glass rod embedded with threads of white glass, threads of coloured glass, columns of air (air twists), or a combination of all three.

Vermiculite – product to slow the heat of the beads down.

Wound glass – Molten glass is wound around a mandrel like thread on a spool, forming a bead.