Functional glass art is made using an almost endless selection of fused glass. Many textures, including reed and herringbone ripple; and styles, such as transparent and opaque compatible glass, are available. Each glass art project goes through a series of steps including design, kiln firing(s) and cold work for specific results. Each is custom made to meet client specifications.
Fused glass and kilnformed glass are interchangeable terms referring to melting pieces of glass together in a kiln. For example, to make a bowl, pieces of glass are cut into circles and fused together in the kiln. Then in a second kiln firing, this round disk is place inside a mold and slowly heated in the kiln so that the glass slumps into the bowl mold to achieve the shape.
Glass fusing is the process of using a kiln to melt together pieces of
glass. If you apply heat to glass, it will soften. Two or more pieces of
glass will stick (or "fuse") to each other. Most fusing takes place in a
temperature range of 1450 - 1500 degrees Fahrenheit.
The most common method of shaping fused glass is slumping, where a mold is used to cause already fused glass to take on the shape of the mold to make- a vessel bowl, lighting fixture, or similar art object. To achieve shaping of the fused glass in or over a mold, the slumping temperature of 1200 - 1300 degrees Fahrenheit is typically used.
Once a glass art piece has been kiln fired, a special treatment known as cold-working can be performed to shape, grind, and polish the edges or surface of the glass. It involves the use of grinding and polishing tools to achieve the desired finished appearance.
Most glass art has a shiny, high-gloss appearance after kiln firing. A matte surface can be achieved through one of a number of treatments once removed from the kiln including sandblasting, acid etching and cold-working. Each treatment results in a different surface appearance; we'll work together to achieve the finish needed for your glass art.
Kiln-forming is the general term which refers to fusing, slumping, and other
glass processes and which takes place at temperatures between 1100 and 1700
degrees Fahrenheit (600 to 925 Celcius). That doesn't sound warm, but it is
when you compare it a glassblower's working temperatures, which often exceed
2000 degrees Fahrenheit.
In kiln casting the glass artist uses a kiln to melt and shape glass pieces
that are arranged inside a mold. This technique is often used to make
thicker glass art such as vessel sinks and countertops where a specific
size, shape and depth is required. Kiln casting is normally achieved with
temperatures greater than 1500 degrees Fahrenheit.
While blown glass, stained glass and glass mosaics have been around for
hundreds, even thousands of years, fused glass is a modern day medium
introduced in the late 1970's and early 1980's. Why the late arrival? It's
because glass pieces need to be compatible in order for them to fuse
together. The various glass pieces you select for your art need to expand
and contract as the same rates when kiln-formed (fused) and then cooled.
If you use incompatible glass pieces, your piece may crack or shatter. The technology of developing compatible glass was in large part advanced by three glass masters in Portland, Oregon who formed Bullseye Glass Company.
Over the past 3 decades compatible fusable glass has continued to evolve and is now available in hundreds of colors. New types of glass have been introduced such as iridescent glass, dichroic glass, frit, stringer, rods, confetti, and billets.
These terms will introduce you to the vocabulary of glass.
- Kiln: A very hot oven used to melt and fuse together pieces of glass.
- Frit: is simply crushed glass. Available in hundreds of colors, frit is
made in sizes including powder, fine, medium, coarse and mosaic.
- Compatible: All of the glass will expand and contract at the same rate in the kiln.
- Inclusions: Glass or metals that are used in fusing.
- Iridescent glass: Sheet glass that has been treated with a coating resulting in a metallic sheen. One of three coatings is applied results in a rainbow, gold or silver sheen.
- Dichroic glass: This process was originally developed for the US space program and it also involves spraying a thin film on the glass. Dichroic glass is quite unique in that it reflects one color while transmitting another.
- Stringer: are long thin threads of glass made by 'pulling' melted glass and
are often used as decorative elements on fused glass art.
- Confetti: The traditional (and dynamic) way of making these very thin, delicate fragments of glass is to blow a very large glass bubble and allow it to burst into shards. Amazing to watch and it's beautiful as highlights on fused glass art.
- Billets: are large, regularly shaped 'bricks' of glass commonly used in kiln casting. When increased clarity is needed for thicker glass items, such as countertops, I use billets to achieve this look in thick slabs.
- Non-glass Inclusions: In limited quantities non-glass materials can be
added to glass for special effects. Gold leaf, copper foil and powder,
palladium leaf, wire mesh and mica powders are some of the materials I use
as design elements in my glass commissions.
- Pot Melt:: A technique used to make custom sheets of patterned
glass. Strips of glass are arranged in a clay pot and is elevated above a kiln
shelf. The glass is fired in the kiln to melt and flow through the pot's
hole. The resulting sheets of glass are one-of-a-kind originals.
did you know?
The Egyptians were familiar with rudimentary techniques ca. 2000 BCE.
Fusing was the primary method of making glass objects for approximately 2,000 years, until the development of the glass blowpipe.