No two pieces of glass are alike, but all fused glass does go through steps that include design, kiln firing and cold working.
Fuse – to fuse glass is a process of firing compatible glass in a kiln, melting the pieces together. In the kiln, each firing process is programed individually to suit the shape, size, thickness and type of glass. Firings typically run 7-9 hours, as unlike pottery, glass needs to heat slowly with strategic hold points. Once it reaches the highest temperature it can then move quickly back to its “annealing” temp and remain at the temperature for an extended time to strengthen the glass piece from within. Finally once the firing schedule is complete, the glass needs to cool to room temperature before it is removed from the kiln.
Slump – generally a 2nd firing for a fused glass piece at a lower temperature, to moldthe glass into a specific shape by way of a commercially produced mold or self manufactured molded form.
Vitrograph (stringers a similar term) – I place compatible glass in a terracotta pot; this is generally varying shades of one color of glass, mixed with approximately 1/3rd of clear glass. The “pot’ is place in an elevated vitrograph-kiln centering the hole in the pot over the hole in in the bottom of the kiln. The kiln is heated to 1700° over a period of 4 hours, once it reaches the target temperature glass begins to flow downward out of the kiln. With Kevlar gloves, extra large tweezers and scissors to cut the glass, I beginning pulling, shaping and twisting the red-hot glass, cutting it at a manageable lengths and landing it on a metal surface. As various shades of colored glass go into the pot and the glass flows from the center of the pot out, each section of glass that is pulled is unique. I form and shape the hot glass as it flows out, sometimes I grab the “tail” and just twist and twist it in a circle; “Twisties” look beautiful when used in a FG piece as the melt their twisting design becomes so very striking. Vitrograph is so uniquely formed it takes on amazing shapes like vines, leaves, birds, signatures…..merely limited by your imagination. I can also pull the glass straight in various thicknesses – this is more often referred to as a stringer. I can purchase Straight Stringers where I buy my sheet glass, by shaped vitrograph is hand-made.
Murrini (Millefiori) I create Murrini from a square stainless steel vessel, it has a little larger hole in the bottom than the terracotta pot allowing a thicker glass flow. Murrini is generally1/4” to 1/2” in thickness (Vitrograph may be 1/32-1/4”). When glass is placed into the SS to make Murrini, it is methodical and systematic. Color combinations and placement of colors and types of glass next to one another are reflected in the finished product. As the 1700° glass flows, each section of glass will result in a different overall pattern within the glass. I pull approximately 18” Murrini pieces, cut them, and then lower them to the metal surface and straighten them while they were still extremely hot. Millefiori is Murrini formed in a flower-design.
In general Fused Glass should never be used in an oven and we always recommend hand washing.