Rev. 3/30/95, 8/22/95, 2/11/97, 11/29/97, 1/3/99,
8/19/99, 2/18/2000, 2000-10-29,
... 2003-01-02, -09-27, 2004-01-03, -09-12, 2005-10-23, 2006-03-06, -06-03,
-07-08
2008-02-05, 2009-01-30
Prepared by Mike Firth
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Glass working activities range from cold to
very hot.
Generally the cost goes up with the temperature, so
this discussion has three sections.
1) A simple list of categories roughly by cost
of working the glass
2) A set of brief descriptions in the same order.
3) A longer narrative giving costs, sources of
information, etc., in the same order.
Exploration of glass using frames
Best Books
About Glass
Uses for Glass (Architectural, etc.)
Glass As Addiction
Because this is my site about furnace glassblowing, here are two detailed descriptions. |
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1) A simple list of categories ordered roughly by
cost of working the glass * With the passage of time, grouping of glass activities into categories have changed. In the early 90's when I started, coldworking, stained glass and glassblowing were common terms. By the mid-90's, lampworking, an old term, had come forward again for torch working glass and not long after, warm glass was used in exhibitions for kiln worked glass that had been categorized with stained glass. Now, about '05, a number of schools are using flat glass, lampworking, warm glass and hot shop with some adding cold working for traditional etching and engraving with sand/abrasive blasting included in flat glass.
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2) A set of brief descriptions in the same order. There are three major groupings of glass working: cold working, warm glass, and hot glass. Most people working with glass end up doing work in more than one area and combining areas has led to some very interesting art. Cold worked glass begins with using copper foil and solder or solid lead came to frame cut pieces of stained glass and beveled clear and mirror. Besides flat panels, foiled glass can be used to make boxes and lampshades. Glass may be vacuum coated with thin metallic films (dichroic) for special effects. Glass may be laid with cement to form mosaics or thicker pieces (dalles) may be held in cement or epoxy so light shines through. Glass may be cut, carved, ground, and polished with wheels and diamonds to make images or patterns. Optical glass may assembled with special glue to appear to put things inside blocks glass that shouldn't be there (e.g. square bubbles, dichroic films.) Glass may be sandblasted or chemically etched to produce frosted patterns. Stained glass work is the most popular. Sandblasted pieces are often used in buildings. Kaleidoscopes are arrangements of two or three mirrors to form star shaped images; the housing for the mirrors may be stained glass or any other material. Glass is also used as a canvas for painting and as a stone for printing like lithographs. Warm glass work involves setting up cold glass and heating it in a kiln, also called kiln working. Glass may be arranged in a cold kiln and the temperature raised until the glass flows (sagging or slumping) or melts (fusing); often colors are fused on a flat surface and the result is then sagged into a form. Glass may also be cast by arranging broken glass in various sizes in a mold and heating it until it flows to fill the mold (pate de verre and kiln casting.) Glassblowing takes two forms, furnace work which is what I do and lampworking
or torch work. Hot glass is melted in a furnace. Furnace work involves a lot more prep (hours) before the first glass can be blown or keeping the glass melted all the time, which is costly. From the furnace it may be poured into a mold (casting.) or it taken out very hot on pipes to be blown and shaped. This last is what I do, mostly, and what my site is dedicated to.
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3) A longer narrative giving costs, sources of information, etc., in the same order. In more detail: Before or after fabrication glass may be covered with thin metallic films (dichroic) in a vacuum facility to produce an iridescent colors. Dichroic glass may be used like any other glass - foiled, fused. etc. This kind of glass is most often used in smaller pieces, fused jewelry and plates and paperweights. An older use of the term referred to glass that was one color in light passing through it (usually red) and another in light reflecting from it (usually green.) Mosaics and dalles are a
relatively low cost activity that has become much more popular
recently. Making stepping stones of glass and cement has
increased as molds become available so the craft involves laying
bits of glass in a reusable plastic mold that provides an
interesting outline. Both involve breaking or chipping small
pieces of glass and arranging them to make a picture or color
image. Some of the most unusual pieces made with glass use modern glues. Pieces of window plate glass may be stacked into sculptures with the layers (and green edge) visible. Optically clear glass pieces may be carefully ground and and then glued with special "water-clear" ultraviolet curing glues to appear solid while putting things inside the glass that shouldn't be there (ie. square bubbles, dichroic films, cities.) The assembled pieces may be ground onto spheres. Careful examination still reveals the interfaces as slight changes in the light flow. Silicone and epoxy glues may be used to join unlike glasses and join glass to marble, wood, or metal for special contrasts. Pieces of glass used in foil or came work can be etched or the etching may be applied to full
pieces of glass, including mirror, used like paintings; a major
business for architectural partitions. Air pressure blasting can
use abrasive or other materials (usually not sand, because of
silicosis) and may produce deep looking effects; the least
expensive blasting equipment (siphon) providing less control than
a pressure pot. Etching can be done with acid pastes, but only a
shallow effect. Blasting requires an air compressors, material
tanks, ventilation, and protection for lungs (respirator) and
surroundings (shielded, filtered room/box.) Silicosis is a risk.
Equipment cost is several hundred dollars, most of it in the air
compressor which must be fairly large. Painting and reverse painting on glass take advantage of the thickness of the glass. Glass has also been used like a stone for printing paper similar to lithography, notably by Harvey Littleton in his later years. Kaleidoscopes are an arrangement of 2 or 3 long slender mirrors inside a more or less decorative shell with something to view at the far end. From a collectors viewpoint, the shell is the most important. Stained glass is a common, easy, shell. A discussion group is at http://groups.yahoo.com/group/kbkb/ signing on to yahoo is required. Warm Glass At temperatures just above fusing, casting and Pate de Verre can be done. This requires a heat proof mold. Broken glass pieces, perhaps mixed with binder, carefully placed, can create pictures. Or glass can be stacked above a mold to melt to a uniform mass. The kiln is heated after the glass is placed and raised in temperature until the glass flows or fuses depending on the desired result. The whole mass is then cooled to the annealing point and annealed for many hours, up to days or weeks, because of the mass of the glass and mold together. Periodical: None known Hot Glass More Hot Glass Molten glass casting is also done from a furnace where the glass is scooped out and poured into a heated mold, which is then annealed. Because of the thickness of the glass and mold, the annealing times can easily run to days of slowly lowering the temperature. Some of the most complicated glass pieces seen today are cast from several different colored glasses, producing shaded effects. Periodical: None known Paperweights are made with a combination of skills, although they can be made entirely on the pipe or its solid relative, the punty. Classic paperweights require much preparation which may include flame working to make millefiori rod or animal or plant figures which are encased in clear molten glass to make the final piece. Modern style abstract glass forms and bubbles are less complicated to make. Paperweights require an extended annealing time that can take days if large. Marbles may be made by lampworking or off hand techniques requiring special tools (primarily graphite pads with hemispheric holes) to make totally round objects. Best Books (Also, you might look at my
longer bibliography page) A GLASSBLOWER'S COMPANION - Dudley Giberson [Joppa Glassworks,
Inc., P.O. Box 202, Warner NH 03278 603-456-3569 FAX 603-456-2138,
e-mail joppaglass@conknet.com] announces via post card his
completion of A Glassbower's Companion, ready to ship in mid-December,
136 pages 300 illustrations, $39 including shipping. The best books on fusing are those by Lundstrom available at
many libraries. "I'll "ditto" Kathy Cowan's advice
- Boyce Lundstrom's "Glass Fusing Book One" is the very
best! I have most every book ever published on fusing, and his is
the easiest to understand and the most comprehensive." AVERY
H. ANDERSON CompuServe. Boyce Lundstrom wrote three wonderful
books that deal with fusing, slumping and casting. .. Kiln Firing
Glass (Glass Fusing Book I) .. Advanced Fusing Techniques (Book
II) .. Glass Casting and Moldmaking (Book III) Many community colleges offer continuing education classes at very reasonable cost on making stained glass objects. My new (2000-3-6) nominee for best book on all aspects of glass working is the 1998 book by glass artist Lucartha Kohler, Glass, An Artist's Medium, [ISBN:0-87431-604-x, Krause Publications, 700 E. State St., Iola WI 54990-0001, orders 1-800-258-0929, 715-445-2214; Dallas Public Lib. CFA 748.2 K79g]. Because Kohler has worked in many of the variations of glass that she is writing about, she gives excellent coverage of almost every aspect of glass working (except furnace glass where casting gets more coverage than blowing and that not much.) More importantly, she seems to give enough information about doing stuff, like glass painting or kiln working or cold working that a person can understand how to do it. This is not an elementary exercise book and it is not a complete coverage of all aspects of glass; it is a good coverage of some aspects of many ways of working with glass with particular attention to kiln worked and cast glass which she has done a lot of. A good list of sources, a glossary, and notes on Safety. The best overall book on a wide variety of glass working activities is probably The Complete Book of Creative Glass Art, by Polly Rothenberg, 1974, which is apparently not in print, but which is available in many libraries and thus by interlibrary loan to all. "500 Photographs Apparently superb introduction to most aspects of doing things with glass; the parts I know are dead accurate. Includes photos, sample projects with all steps. Leaded stained glass, Bonded glass (epoxy), Fired glass, Painting glass, Glass jewelry, Blown Glass, Glass Sculpture & Architectural Art." Mike Firth Glass is a material made from silicon oxide (quartz, sand, etc.) made easier to melt with chemicals including limestone, soda, and potash. When cold and broken, the pieces are usually very heavy and very sharp. Obsidian, a volcanic glass, was used to make sharp weapons and tools by stone age peoples around the world. Yet if heated glass is sharply cooled by a heavy long blast of cold air it becomes extra tough tempered glass, but if that toughness is scratched or nicked, the shattered pieces are round edged chunks that can be rolled in the hands, as can be seen after many automobile accidents in the remains of side and rear windows. (Front windows on cars have a layer of plastic to keep people from going through.) The properties of glass vary with the formula which can be tuned for different results, just as cast iron is different from cast steel is different from stainless steel. As a midpoint figure, we might take the specific gravity to be 2.4 so a cubic foot weighs about 150 pounds. Unlike many materials which melt at a specific temp, like ice at 32°F (0°C) or lead at 621°F (327°C), glass is squishy to liquid over a long range of temps. Art glass for example is commonly worked as a thick liquid at 2050°F while it is soft enough to sag slowly under its own weight at about 1000°F. Glass does not easily blend when two colors are heated and melted together. This allows a glassworker to make pictures by aligning rods of various colors and then reducing the picture size by pulling the glass. Yet a thin layer of clear colored glass, applied to the inside of a thick layer of clear glass can make the whole piece take on the color. Like all materials, glass changes size with heating and cooling. Unlike many other materials where related materials (say kinds of steel) behave similarly, different formulas and colors of glass may expand and contract differently. The measure is the COE - Coefficient of Expansion. Because glass is brittle when at room temp, differences in COE at hot temps can introduce strain that will crack the glass. Unlike most materials in which changes in the heating and cooling schedule may produce various results (changes in grain size and hardness in steel.) but do no harm, with the exception of tempered glass, glass must always be cooled under controlled conditions, annealing to keep strain in the glass as low as possible. Glass normally has to be cooled over several hours, longer for thicker glass, over the range from the annealing point, about 900F (13 dPas viscosity) to the strain point (about 600F for art glass, 14.5 dPas.) Faster cooling results in broken glass, the sound of breaking glass being common in studios as pipes are set aside in bins with fragments of glass attached. 2003-01-11 [In answering an newsgroup query, it occurred to me to add some notes on uses of glass that fall in the categories discussed above, but from the opposite point of view, not doing them, but buying them.] The page Glossary of Blown Glass Objects GLOS-OBJ.HTM lists a great many tableware and decorative glass objects, so this list is focused on groups of non-blown objects.
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From: "Mike Firth" Links to other sites - perhaps useful http://www.signmakershop.com/links/glass.html
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Because this is my site about furnace glassblowing, two descriptions about that. |
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