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Glassblowing Terminology and Fundamental Techniques

Photo by Amalgamation, Jacob Patrick, and Ben Holmes.

New to the world of glass? Need a refresher on terminology? This post covers select basic glassblowing terminology including tools and fundamental techniques.

Maestro, Lino Tagliapietra, has openly shared that no matter how creative of an artist you may be, you must get the basics right to produce great work. Understanding glassblowing terminology is crucial.

Back when Lino conducted a master class for MIT Glass Lab instructors, he shared the following information with Denis Paiste of the Materials Processing Center: “A half-hour to an hour of concentration on these few basic things can help you realize where you are making mistakes, Taglipietra says. Holding the pipe too close, for example, is a mistake that can result in someone getting burned if someone bumps you. ‘You must move in the correct way,’ he says. ‘The balance, how you move it, you want kind of an elegant movement.'”

ANNEALING | Cooling molten glass slowly to relieve stress.

BATTUTTO | A technique that means “beaten glass”. The surface is textured using grinding discs to create tiny dents of varying depth producing a distressed surface similar to the “hammered” surface seen in metalwork.

BIT | A freshly gathered mass of molten glass from the furnace. Bits are also known as gobs.

BLOWN | Glass produced by the traditional process of using blow pipes, punties, and hand tools.

BLOWPIPE | 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.

CALDA | A repeated process for shaping the glass object by inserting the glass attached to the end of a blowpipe or punty into the furnace where it softens so that the glassmaker can shape it.

CANE | Small  rods of colored or clear glass used for different techniques. Cane types include: filigrana, latticino, murrine, reticello, etc.

CASED GLASS | The application of a thin layer of clear or colored glass over another layer of glass.

COLD WORK | General term for techniques that do not involve hot glass, such as cutting, grinding, etching, polishing, sandblasting and laminating.

COLORED IN FUSION (COLORI IN FOGO) | Glass that is colored while still molten using oxides or mineral salts.

CONSTRUCTED | Objects of glass that are glues, epoxied, fused, bolted or otherwise joined together.

CULLET | Raw glass chunks or marbles, often broken from a cooled melt that can be re-melted with fresh ingredients.

ENGRAVING (INCISIONE) | Abrading or stippling the surface of glass white a copper, diamond, or other wheel or tool.

EPOXY RESINS | A synthetic resin used to bond glass in laminated or sculptural construction.

FILIGRANA or FILIGREE | A composite cane, spirally deformed, whose internal linear pattern is made from lengths of pulled, fused, and bundled canes that are colorless, white, and colored from time to time.

FERRO | A piece of steel coated clay that is used as a plate under murrain when they are fused.

GAFFER | The lead of chief glassblower.

GATHER | A glob of molten glass.

GLORY HOLE | An opening on a glass furnace that is used for reheating the glass.

HOT APPLICATION (APPLICAZIONI A CALDO) | A technique involving the application of threads borders, handles, etc. of various shapes, colors and sizes during the working of a glass piece.

HOT COLORING WITHOUT FUSION (COLORAZIONE A CALDO SENZA FUSIONE) | A unique coloring process that involves the insertion of chemical substances or other elements between two layers of clear incandescent glass.

ICE GLASS (VETRO A “GHIACCIO”) | A technique of plunging a blown piece, while hot, into a tub of water, achieving a crackled appearance.

INCALMO | A difficult glassmaking technique consisting of welding together two hot open-sided blown glass objects generally of different colors along their two edges of equal circumference.

MAESTRO or MASTER | A glass artist who has achieved the highest level of skills.

MARVER | A flat metal surface sed for cooling and shaping the hot glass.

MILLEFIORI | Millefiori dates back to the XV century on the island of Murano, and it was then practiced in the XIX century. Glassblowers used to create pieces of art with a particular design that consisted in solid or perforated glass canes characterized by concentric layers of different colors creating star or flower shapes. The surface of the glass decorated like this reminds us a flower field, hence the name.

PEA | The first stage in the making of all hollow glass objects. Once attached to the blowpipe, the pea is rolled and rounded as required.

PUNTY | A steel rod or tube used in the blowing process.

SANDBLASTING | The use of compressed air to project an abrasive (sand, aluminum oxide or silicon carbide) against glass to create a matte surface or penetrate a surface or a layer of color, revealing an underlying color.

SHEARS | 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.

SLUMPING | The technique of heating glass until it slumps into a  |desired shape as configured by a mold.

TOOL | 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.

VETRO A CANNE | A technique consisting of placing canes or rods that are solid and cylindrical or flat next to each other in different color combinations, melted and then blown into the form of a glass object.

VETRO MURRINO | A type of hot-worked mosaic, where small pieces of glass are fused together.