Do you remember the first time you saw sunlight streaming through a stained glass window? Did you fall in love with glass? Many people begin their glass journey by making a window or mosaic stepping stone. Then some move on to working with glass in other forms.
What follows are descriptions and photos of glass techniques used by our members to create their art. More examples can be seen in our Members’ Gallery. If you want to learn how to do it yourself, many of our members teach these techniques or contact the Play Day coordinator and we’ll see if what you want to know about can be the topic of a Play Day or General Meeting.
Glass work falls into three broad categories based on the how high a temperature you fire the glass to/ or if you heat it up at all):
Cold Glass (or “Flat Glass”) includes stained glass, mosaic, and appliqué techniques. Stained glass artists create windows by cutting pieces from large flat sheets of glass, wrapping the pieces with either lead came or copper foil, and then assembling the pieces with solder into finished artworks.
For Appliqué, instead of being encased in metal, the cut pieces are glued to a substrate and grouted. Mosaics traditionally start with small glass pieces or cast glass tiles (“tesserae” and “smalti”) instead of sheets of glass. These small pieces are nipped to shape, if necessary, and used to make the design, like the dots in an impressionist painting.
“Cold” glass techniques also include surface treatments such as etching, sandblasting, silvering, guilding, glue-chipping, and polishing. These can be used to further enhance pieces created by any technique.
Hot Glass includes glass blowing and lampworking (also called flame- or torch-working). Artists manipulate glass which is fully melted in a hot furnace (“glory hole”) or worked with a torch. These are the candy-makers of the glass world: hot glass artists see their results immediately. The finished hot pieces must be cooled in a controlled manner in a kiln to keep the glass from breaking. This is called annealing and the kiln is called an annealer or annealing oven.
Warm Glass (or Fused Glass) includes all those techniques in which the glass is partly or fully melted in a kiln. Artists in this group are often called “fusers”. They use time, temperature and gravity to coax the glass into doing what they want while it is being heated in a closed kiln instead of directly manipulating it. Think of them as the glass bakers: fusers spend a lot of time setting things up and then turn on the kiln and leave it alone, sometimes for days.
Modern fusers program their firing schedule into their computerized kiln controller instead of staying up all night to control it manually. The controlled cooling to anneal the work is also part of the firing schedule. Since they don’t need as much equipment as hot glass workers do, this is a good path for artists looking for techniques they can do in a home studio.
Temperature effects: Tack fuse, where glass just starts to stick together (about 1225 degrees F)
vs. full fuse, where glass is fully melted flat (about 1500 degrees F).
Accumulated time at peak temperature has an effect too. For example 10 minutes at 1425 F has a certain amount of effect on melt. 30 minutes at 1425F is about half way to the same effect as 25 degrees hotter for only 10 minutes.
Glass starts getting soft at about 1100 degrees F. As you go hotter, stacks of glass thicker than 6mm will spread out if given enough time and not contained.
Simple shaping, Slumping, draping, and drop molding, are done at about 1200F for a short time. At that temperature glass merely bends like a warm chocolate bar.
Greta Schneider placed a flat disk of glass in this mold and slumped it to produce this red dish.
Greta Schneider also makes dishes with a drop mold like this. The drop needs to be watched and stopped when the dish gets as long as desired or you may get a puddle.
Bob Heath coated a disk of clear glass with green powder, fired it, used a drop mold to shape this vase, then sandblasted away the green to make the pattern.
Gravity vs. surface tension:
At about 1500 degrees F (full fuse) pieces thinner than 6 mm will try to become 6 mm thick. Small scraps will bead up to become “frit balls”.
Most sheet glass is 3mm thick. This means 1 sheet thick will thicken and shrink inward with firing, 2 layers of glass won’t change size much, and 3 layers or more will expand until they become 6mm thick unless you constrain the volume with a container of some sort.
Kiln carving, like this cat from Greta Schneider, can be done by draping glass over cut out fiber paper shapes or holes. If you want a flat top you put a dam around it, use more layers of glass, and go hotter.
Get members’ favorite tips on glass cutting, tack fusing, roll-ups and other parts of the process by joining the Guild and coming to our events.
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