Glass casting is one of man's oldest art forms. Archeologists have found Mesopotamian glass beads dating back to 2500 B.C. and the Egyptians molded and twisted glass in its hot, liquid state calling it "stone of the kind that flows." In 63 B.C. the Romans conquered the Syro-Palestine area bringing glassmakers to Rome. Soon after the word "vitrum," meaning glass, entered the Latin language.

Even with today's technology, the glass casting process can be quite arduous. From a creative standpoint, however, the drawn out process provides the artist opportunity to focus on sculpting, coloring and cold-working (polishing, etc) separately. The aesthetic range seems limitless when the artist also has access to a palate that ranges from transparent to opaque. This high ceiling for beauty combined with the great difficultly in actually achieving it has made glass art one of the world's most respected forms of art.

The glass casting process begins with sculpting a model. This is most often done using wax or clay . If the sculpting is done in anything other than wax a rubber mold is made in which wax is poured into to make a wax replica of the original sculpture. Plaster mixed with myriad of other potential materials is made into a slurry and poured over the original wax sculpture to make a refractory negative. Once the plaster hardens, the wax is melted out, and an empty mold is left. The wax is said to be "lost" and hence this is referred to as the "lost wax technique".

In ancient times, the mold was filled with sands that contained impurities that gave the glass color, such as iron, which produced a light-green tint, manganese, which produced pink and violet, and sulphur which gave rise to yellow and dark green colors. Ancient glassmakers also deliberately added other minerals to color the glass . Almost colorless glass could be created by selecting sand free of silver, or by using antimony as a de-colorant. Colorless glass became the preference by the 3rd century AD.

By the early 20th century, glass casting had evolved into the French style of pate-de-verre (meaning "paste of glass") with French masters such as Francis-Gabriel Decorchement, Amalric Walter, and Argy Rousseau. Pate-de-verre was often referred to as "the phantom technique" during the art nouveau period, because elements of the technique were kept secret from new or competing artists.

Pate-de-verre involves applying powdered glass of different colors into the mold, as if it were paint. The different color powders fill in the deepest relief of the mold first, so the "painting" is done in layers. The powders may be moistened, or mixed with an adhesive that will burn out of the mold while firing in the kiln. As HibriGlass artists are working, they paint the powdered glass into the interior sides of the mold. If done correctly, no additional interior mold is needed to hold the glass in its place. Most other artists choose to use an interior mold, but color streaking usually occurs. When the piece fires, (around 1,400 F) the particles melt and bond with each other creating a frosted, or nearly opaque glass that is rich in color and texture. Some air bubbles between glass particles are usually visible. The highest quality pate-de-verre is very thin, semi-transparent, and has a fire-polished interior surface due to the glass particles fusing without contacting a plaster interior. Pate-de-verre is widely considered one of the least forgiving, yet most rewarding, glass techniques. As such there are only a few people alive who can execute the technique at a quality comparable to the Art Nouveau masters.

The pate-de-crystal technique differs from pate-de-verre in particle size and composition of glass. In pate-de-crystal, the mold is filled with different color pieces of leaded crystal that range in size from fine particles to pebbles. Color application may be random and flowing, or it may be controlled, but it is usually not as precise as pate-de-verre. Using larger chunks of glass increases transparency, and the highly leaded crystal gives rise to a beautiful sparkling finish not found in other forms of glass art. Pate-de-crystal pieces may fire up to 1700*F.

In both pate-de-crystal and pate-de-verre, the annealing (or cooling) phase is slow, and monitored by the kiln's computer to make sure that the glass equalizes at a consistent temperature so as to prevent cracking. The thicker the crystal, the slower it must anneal. Sometimes de-vitrification occurs if the cooling rate is not perfect for the different minerals contained in the different colors of glass chosen - there are many different variables! De-vitrification may be in the form of: wrinkled skin on the surface of the glass, or discoloration/muddied mixtures of colors. Once the piece has reached room temperature, it is submerged in water to dissolve the plaster mold, and the cold-working process begins.

"Cold-working" refers to any work done to the glass once removed from the kiln. First, any rough edges of the glass are ground with diamond pads or a lathe. Then polishing with various abrasives is often needed to get the highest sparkle, or a glass piece may be sandblasted to give it a frosted or etched appearance. Some HibriGlass pieces are gold or silver leafed from behind to reflect light back through the glass, eliminating shadows and adding to the richness of color. We may also use metal coatings and acid patinas to obtain rough weathered looks in contrast to the sparkling shine. The newest technique in the HibriGlass studio is electroforming metals onto the surface of the crystal.