Glass Art Dictionary, Terms, and Phrases
Art Glass Working Terms & Phrases

Annealing Oven
The process of gradual cooling of the outside and the inside of  the molten glass to assure that the glass won’t cool to fast causing cracks or breaks.

Assistant
The glassworker that works directly for the Gaffer.  In some situations, there may be several assistants depending on the size of the project.

Blank
A molten glass object ready for the further creation of the Art Glass piece.

Block
The forming tool used for the shaping of the molten glass.  The “Block” is usually made of cherry wood and is “wet” while used with the hot glass.

Blocker – The glass worker that actually “blows” the first bubble through the blowpipe and then subsequently transfers that blow-pipe to the Gaffer.

Blower – The glass worker that blows the air through the blowpipe (within the mold or freehanded).  Upon occasion, the gaffer might do the blowing of the air themselves to have more control.

Blowpipe – A steel pipe with a air passage way throughout it’s entire length.  One end has the mouthpiece and the other has the larger built up area for the molten glass to gather and blow the bubble on.

Bubbles – Gases in the molten glass while melting in the “pit” get trapped.  The hotter the molten glass along with the purity of the quality of the glass can greatly diminish this problem.  While gathering the molten glass those bubbles will be transmitted to the actual art piece itself.  Some artists do like the bubble effect and use them in their works by forcing a bubble.  Installing bubbles may me made with a sharp object being punctured into the molten glass or countless other methods.

Burner – Runs the air and gas mixture control for lampworking.

Burn-mark  - The residue left from the usage of a newspaper ash in the assistance of shaping of the molten glass.

Button – A small usually clear amount of molten glass placed on the “working end” of the art piece project to assure proper connection of the glass to the pipe to avoid dropping damage.  A button may also be used as a part to the actual glass project to enhance a particular art piece.

Caliper – Tongs that help create and control the molten glass piece.

Cane – A cross section of glass made by pulling and stretching molten glass from both ends.  Several color 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.

Carving – Removing excess molten glass off of the working piece.

Casing – Placing an additional layer of glass over and existing layer of another color.

Casting – The process of pouring molten glass into a form designed to receive that glass.  After the glass has cooled, that mold or the removing of the sand will then reflect the filled image.

Chill-mark - Any time and instrument is used on hot glass there's a potential for it to leave a cooled surface that refracts light differently.

Chord - These are lines of clear glass that have a slightly different expansion coefficient enhance refract light at different rates.

Chunked – A glass piece that has been badly damaged.

Cold Working - Any work, grinding, surfacing, and drilling that is done on the glass that has been finished after the annealing process is completed.  Working without heat. 

Collar – A ring that is used to hold the cane glass into place on a working piece.

Color - 99% of the color used comes from Germany or Bulgaria. The transparent colors are nearly all black until blown out in a piece and come shaped like a small rolling pin. The opaque colors are most often the same color as they started before melting.

Contemporary Glass – Artist designed glass exclusively for their own creative use.

Cord – Visible deficiencies in the glass quality product itself from streaking to slight color haziness.

Cullet – Mixing slag, scrap or other extra glass materials into a  pit to assist in the melting process.  This also reduces the quality of the glass product itself.

Cutting – Grinding any pattern into the glass by using a consistent speed rotating wheel coated with either cloth, diamond dust or an abrasive.

Cut-to-Clear – Showing the under layers of the glass by cutting however many layers needed to complete the desired effect in the glass.

Double Overlay – Coating a glass works twice.

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

Etching Decoration – Using acid to etch the glass.  Strengthen or get an chemical reaction or effect with the glass surface.

Finisher – The glass worker (generally the Gaffer) that puts the finishing touches on the glass before it goes into the Annealing Oven.

Flashing – Quickly placing the working glass into the Glory Hole to reheat the entire piece to assure that the glass will be pliable and keeping it safe from cracking.

Fluted – The vertical lines, grooves or designs in the glass.

Founding – Heating the glass to a proper usable temperature.

Fritt - Clear or opaque color that is crushed and graded to specific sizes.

Gaffer - The senior member of the blowing team in charge of the entire production of a project

Gather – Placing molten glass on the end of the blowpipe or pipe for the further development of that glass project.

Gathering - obtaining a layer of clear glass over a subsequent layer of glass.

Gilding – Using leaf (golf or silver), painting or effects to add interest to the surface of the glass.

Glory Hole – The opening of the furnace used to keep the glass hot and workable.  Several different sizes may be attached to a large furnace or you might have only one size on a small one that rotate open and closed depending on were the glass project is at. The cylinder is usually heated up to 2300 degrees.

Hand Blown – A glass project is handmade and was not assisted by machinery.

Iridescence – Spraying a shiny metallic finish onto hot glass.

Jack - A tool shaped like huge tweezers used to manipulate hot glass.  Making a Jack line is often the line that will be used to separate the glass work from the blowpipe or pipe with the droplets of water.

Knurling – A glass band or bead wrapped around a larger project.

Lear -  A gigantic oven that is computer-controlled to relieve stress during the annealing process.

Marver – A flat steel plate that’s used for the picking up color chips or the shaping of molten glass on the end of a blowpipe or pipe with a rolling action.  A Marver can also help in the uneven cooling of the glass for a desired effect.

Mould Blown – An open ended cylindrical designed to create effects or grooves in the molten glass by blowing into the blowpipe while in the mould vertically.

Murrini – A cross cut piece of glass (with a design or color pattern) used in the creation of  a larger glass works.

Necking – Reducing an end of a blown glass to form a bottle neck.

Overlay – A thin layer of clear or colored glass is folded, formed or coated over another.

Overshot Glass – Rolled molten glass is covered with splinters covering the surface as a final completed surface.

Parison – The first small bubble at the end of a blowpipe.

Pattern Mould – Pre-shaped patterned on the molten glass before the bubble is blown.

Pegging – Placing a Parison (small air bubble) into a gathering pit.

Pick-up Decoration – Picking up color from a Marver before blowing the glass out.

Polishing – Buffing the glass cuts or grindings to a bright clear luster.

Pot – A holding area for molten glass where the glass is continually kept at a designated heat for gathering.

Power – Is the ground glass that is put into the Pot for melting the final molten glass that will be used by the hot glass workers.

Punty -  Is the hot glass or gathering that is placed on the receiving pipe for transferring the glass work that is currently connected to the blowpipe. The technique used to change the end of the glass that is being worked on.

Rag – Tick layers of wet newspapers folded to provide a cool safe pad for the glassworker to shape the hot molten glass.

Ringer – the glass worker that applies the ring for glass to the larger piece.

Rondelle – A flat blown glass that was spun hot.

Sandblasting – A method used to remove layers of glass.  A cloudy dull finish will result with every layer removed.  Some artist use the sandblasting process to remove enough glass to actually go through the glass for different effects.

Satin Glass – A acid matt finish or frosting.

Sawing -  Cutting glass with a rotating wheel with a blade usually diamond tipped.

Scavo – A process where a corrosive chemical is added to the surface of a hot glass while cooling to give the surface a rougher matt finish.

Sculpting – Handmade free forming solid glass works designed while in molten glass form.

Shard – Glass fragments usually colored of which would be rolled or melted into a working piece for the additions of colors of textures is not melted all of the way.  Different colors melt at different temperatures lending creative textures with variation.

Shears – Glassmakers scissors that are used for the cutting, trimming and shaping of hot glass.  Usually very primitive in design with heavy gage steel.

Silesia – The main ingredient of glass used for art glass.

Silveria – Is a type of art glass with incased silver foil.

Slumped – Flat glass that is melted to take the shape of the form designed to sink into taking the actual shape of that form.

Sodium Flare – The bright light that is given off of 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.

Soliflore – A French term for a vase with a bulbous body and a long drawn out neck for a single flower.

Spatter Glass – The glass with flecks of contrasting color rolled into it.

Sputtering – A metal coating process for the glasses surface.

Stretch Glass – A cracked iridescence on the surface.

Strike – The change in the color of the surface after the glass piece is reheated with intense heat on that surface.

Stringer - Like cane but applied from a molten glob of color over the surface of hot glass.

Teardrop – A glass shape that is usually blown from above and allows a consistent growth of a glass blown into it.

Thermal Shock – The cause by a sudden shift of temperature hot or cold causing the glass to break, crack or shatter.

Thermocouple – Bimetal probe that measures the kiln’s temperature.

Tongs – Glassmakers tool for picking up, transferring and applying water to the Punty to remove the glass piece from the pipe of blowpipe.  

Virtual Production Replications –  is the remaking and replacement of an unattainable (non-art) original "production" glass piece with an as close as possible custom made glass piece for repair, recovery or restoration for historic purposes, etc.

Wetting Off – The separation line for the glass work from the blowpipe or pipe uses cold water to fracture control the break and separation.

Wrap – A term used for the heavy outside bead of glass that is used generally for creative style sometimes used as a contrasting color from a vessel.

Yoke – The weight support for the glassworker while in the glory hole while being flashed.