Like so much in modern society, glass and glass art has benefited from advancements in technology. Glass was most likely discovered accidentally when sand (silica) melted and fused in cooking fires. However, archeologists have established that humans were purposefully making glass objects for utilitarian and adornment purposes for thousands of years with ancient Egypt and Mesopotamia, followed by Rome, being centers for advancement of the art.
Rudimentary glassblowing, a major advancement, was first developed in Jerusalem in the first century BCE. This new technique quickly spread throughout the Roman Empire.
Opening a bowl with "jacks"
Other glass art techniques, such as stained glass, casting, fusing, and mosaic, continued to develop (for example, stained glass rose to prominence in the cathedrals of Europe during the Middle Ages; 5th to 16th centuries CE). However, it was glassblowing that came to dominate. What is now Murano, Italy, quickly became a center for glass art and, even though there are now more glass artists working in Seattle than in Murano, it is that Venetian island that is still held to be the birthplace and center of modern glass art.
Today, glass manufacturers cater to the special needs of artists by producing a huge palette of colors and by precise quality control in production. NASA made its contribution to glass art when it required a special, non-glare coating for space ship windows and helmets. To meet the need, glass manufacturers borrowed from a method of coating glass with very thin layers of metal oxides that had been developed in Germany more than 100 years ago. The unique reflective/refractive properties of this "dichroic" glass result in vivid and changing colors as it is turned in the light. Glass artists quickly adopted it for their own explorations.
While the equipment and the availability of art quality glass have changed over the centuries, the basic method of creating art with glass has not. For most glass art, the artist needs a supply of compatible glass and a source of heat. Depending upon the technique used, the source of heat can be a furnace, a kiln (oven), a torch, or a combination of these. Again depending upon the technique being employed, working temperatures range from 1,100 to 2,400 degrees Fahrenheit.
Compatibility of glass refers to the rate of expansion and contraction as the glass is heated and cooled. Annealing, or controlled cooling, of the glass is critical. Work can crack or break in the kiln (or even months after coming out of the kiln) if it is not properly cooled. Annealing times of one to two months, or more, are not unusual in very large pieces.
Functional and decorative glass can be produced commercially by machine, but it takes the hands and the heart and the practiced skill of the artist to produce something truly beautiful and unique. It is from that quality and uniqueness that the value of Handmade Glass Art found on this website derives. No two pieces are ever exactly alike.
Blown Glass Art
Inflating molten glass, rather than pouring or wrapping it, was initially experimented with in Jerusalem during the first century BCE. The new technique spread throughout the Roman Empire and the process was refined and passed down through the generations. What is now Italy became, and remains, a renowned center of glass art.
Using a torch for heat while
blowing to expand the neck of a vase.
For many centuries after it became popular, glassblowing was only done in large factories. It was not until the 1960's that the technology for the required furnaces and kilns was scaled down to permit one individual to be both designer and maker. This is what is referred to as the American Studio Movement. Even after the Studio Movement, glass blowing, in what today are called Hotshops, is generally a group endeavor. Simple pieces can be created by a solo blower. However, at least one assistant is required to create large-scale pieces with complicated patterns or attachments.
The term "glass blowing" is now used for any piece created in a Hotshop setting, whether it is inflated or solid sculpted. After the first "gather" of molten glass is removed from the furnace at the end of a rod or tube, additional colors and successive layers are applied as the glass is shaped with a variety of ancient and modern tools to create a sculpture, plate, vessel, vase, or bowl.
Due to the weight of the glass at the end of the long tube, extreme temperatures, and delicate timing, the process of glass blowing is both challenging and rewarding.
Cast Glass Art
Casting uses a mold to shape the glass into its final form. The three main methods for casting glass are hot-casting, kiln-casting, and pate de verre.
Pouring molten glass into a mold.
In hot casting, a ladle is used to scoop molten glass (at about 2300 degrees Fahrenheit) from a furnace and then pour it directly into a mold. Most commonly a sand mold, very similar to metal casting, is used. This is an "open face" process where the model or design is pressed directly into the surface of the mold.
Kiln-casting utilizes a mold filled with pieces of glass (billets, frit and/or powders). The mold is then placed in a kiln and heated until the glass melts and fuses to form a solid cast glass object. Alternatively, a container sitting above the empty mold in the kiln is filled with glass and the glass is heated until it flows into and fills the mold.
Pate de verre (French for "paste of glass") uses a paste of powdered glass and a binder that is carefully placed or "painted" on the inside surface of a mold to create the desired color-pattern and design. The mold is placed in a kiln and heated until the glass fuses.
Depending on the glass used, and the desired result, temperatures for Kiln-casting and Pate de verre range between 1200 and 1550 degrees Fahrenheit.
Kiln cast and pate de verre molds are almost always made of plaster mixed with other materials to resist cracking and high temperatures. The models or designs are generally made of clay or wax that is then encased in the plaster mix to create the mold. Once the mold has hardened, the clay or wax is removed, leaving an exact copy of the model to be cast. Clay needs to be dug and washed out, so designs aren't as intricate as wax castings. Wax models can be very intricate and complex since wax melts and can be burned out. Use of a wax cast is the same technique as in the classic "lost wax" process used to create fine jewelry.
Cold-Process Glass Art
Glass is often thought of as requiring heat to shape. Heat may have been required to produce the glass but cold-process glass art is created without the need for furnace, kiln, or torch. Glass can be painted, printed, laminated, etched, engraved, sandblasted, cut, polished, glued and assembled to create unique art pieces. Glass can also be a component in mixed media pieces with other materials.
Laying out a glass mosaic design.
Stained glass and mosaic art have been produced for thousands of years and are still sought after forms of art today. Stained glass flourished in the Middle Ages with the assembling of glass pieces using lead seams to decorate the windows of many European cathedrals and Tiffany lamps dating to the 19th century are world-renowned. Mosaic glass art involves assembling pieces of glass into a picture, abstract, or "painting" on an adhesive background. Today examples of early Middle Eastern, Greek, and Roman glass mosaics are prevalent in the remains of public buildings.
Kiln-Formed Glass Art
The kiln-formed technique can involve one or more of a number of different processes (fusing, slumping, bending, draping, and sagging) all performed using the heat of a kiln. Artists using this technique create a pattern, picture, or design by fitting together and/or stacking colored pieces of glass sheets, stringers (thin rods), and/or frits or powders (ground glass). The resulting assemblage is then placed in a kiln and fired at sufficient heat to cause it to fuse (melt together) and form a single piece.
Glass designs ready for fusing inside a kiln.
Firing temperatures range from 1100 to1550 Fahrenheit. Firing at the high end of the range is called a "full fuse." Firing in the middle range is known as "tack fusing"; the pieces of glass adhere to each other but do not fully melt together. Firing at the lower end of the temperature range is where the glass is shaped. It can be bent, draped, sagged, or slumped using a mold. All of these techniques can be applied to a single piece of glass art in separate firings to add depth, relief and shape.
Fusing glass fell out of favor following the advent of glassblowing in the first century BCE. It began to revive in the early 20th century but it was not until the 1960's when glass manufacturers gained the ability to consistently produce compatible glass in a rich palette of colors that this glass art form saw a true renaissance.
Lampworked Glass Art
Lampworking (today also known as torch-working or flame-working) derives its name from the original use of oil lamps as the source of heat and the use of blowpipes or bellows to obtain a sufficiently hot flame to melt the glass. Artists working in this technique today use a torch (commonly fueled with propane and oxygen) to heat rods or tubes of glass to a molten state.
Creating a glass bead.
The basic technique in bead making involves use of a mandrel (stainless steel rod) dipped in a clay-like substance called bead release. Molten glass is wrapped around the mandrel to form the basic bead. From there, what can happen next is limited only by the imagination. Beads and pendants for jewelry most often use soda-lime (soft) glass.
Delicate and intricate sculptural pieces and ornate goblets and dishes can also be created using a torch. These are primarily produced using borosilicate (hard) glass which is less sensitive to temperature change (think Pyrex). Instead of a steel rod, the art piece is shaped at the end of a glass rod that is removed when the piece is finished.
As with all warm and hot glass art creation, a kiln is required for annealing; the process of controlling the rate at which the glass is slowly cooled to room temperature.
Lampworking is also used to create the glass tubes for neon signs and to shape scientific tools for use in science laboratories.
Wearable Glass Art
Wearable Glass Art is the end product of artists' creative talent in one or more of nearly all of the techniques represented on these web pages. Wearable glass art may primarily be thought of as jewelry but it is also used in a wide variety of other ways. Wearable glass disk was so precious that it was used in the fifth century BCE to send emperors of China to the afterlife. Today we wear clothing that has glass "gems" incorporated into it.
Designing and stringing a necklace.
Glass beads and tiny sculptural pieces produced by artists using a torch are incorporated into necklaces, earrings, and bracelets. Fused glass jewelry pendants, belt buckles, scarf ties, pins, and more come out of the kilns of other artists. Others work without heat using "found" glass such as beach glass or other recycled glass as their primary material. Still others search for vintage glass beads, sometimes hundreds of years old, as their choice of focus in creating new pieces of jewelry or wearable glass art.
In order to finish a piece of wearable art, most artists have also learned skills in working with precious metals (wire work and fabrication). Gems, semi-precious stones, pearls, precious metal beads, antique beads, and other quality materials are also often used in the finished piece to complement the handmade glass components.