Working
with Glass
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Today
glass is worked in an astounding variety of ways, from glory holes for blowing glass to
grout and cement for glass mosaics. So far I've contented myself with 3 methods: lead
windows, copper foil windows and fused glass. I've dabbled in other methods but, with a
background in drawing and painting, making pictures is what I love and these 3 methods
allow me to do that.
Leaded Glass 
Of the 3 methods, leaded glass is the most traditional. It lights the walls of European
cathedrals and is still the method of choice for many artists today.
Leaded glass involves cutting pieces of colored glass to match a master drawing, then assembling the window using lead came. A lead came is a long spaghetti of H-shaped lead. The edges of the glass fit into the sides of the tipped over H with the crossbar (or heart) in between. As each glass piece is put in place the pliable lead is bent along its edge and snipped off at the corner. Once the window is assembled each lead intersection is soldered, on both the front and back. Lead is soft so strength is supplied by a process called puttying. Putty is pushed in between the lead and the glass to hold everything tight and is cleaned up with whiting, similar to plaster of paris, and a bristle brush. Once the putty has dried the window is complete. While leading is ideal for large windows with smooth curves and straight lines it has serious limitations. Although pliable, the lead does not allow for tight curves and intricate detail, and intersections of multiple leads tend to become big blobs of solder. For those who want more detail in their work, copper foil is the way to go. Copper
Foil Method Again the glass is cut to shape but this time copper foil is used. The foil is actually a roll of thin copper tape with adhesive on the back. Each piece of glass is wrapped by pressing the edge against the adhesive, bending the tape over the sides of the glass and burnishing it down tight. The width of the tape determines how wide a margin of lead will eventually surround each piece. When the pieces are assembled the artist runs a bead of solder down each seam, front and back. Then the window is cleaned and ready to install. Although copper foil allows for more freedom of design and greater detail, the effect is much the same. The artist is forced to put dark lead lines between each piece of translucent glass. Only fusing allows the artist to eliminate those lines altogether. Fused Glass Fusing is the process of heating glass in a kiln. It can take many forms from fire-polishing, just rounding off the edges, to full firing where glass is heated to a liquid state and bonded into one piece. When making a fused window the pieces are cut out just as for a copper foil window, but to assemble it, the glass is first set on a base sheet of clear glass. Once each piece is free of dust and fingerprints which might fire into the glass, it is set in the kiln and fire it to around 1500 degrees. When the piece cools it is a solid piece of glass with the image bonded right in and no heavy lead lines to distract the eye. Fusing also allows freedom in other ways. Glasses can be layered to change or blend colors, frit, a powder of ground up glass can be added for effect, or the whole thing can be slumped over a form to give it shape and depth. Yet fusing, too, has its limitations. Different glasses can expand and contract at different rates during firing causing the piece to crack unless compatible glasses are used. So far only a few manufacturers are making glass that is tested to be compatible, but as the demand grows more lines become available. Glass can be finicky, too much heat causes bubbling, heating too fast causes cracking and colors may change when heated. Despite that, fusing offers the artist some fascinating possibilities and often the limiting factor is only the artist's imagination. Working with glass is a fun and rewarding experience. I encourage anyone who is interested to pick up one of the many excellent books on the subject and dig in. |
