Saturday, February 12, 2011

I just spent a wonderful day at ArtifactsPlus, a new art supply store in Petrolia, ON with Marie-Josée Girard, a glass artist from Georgetown, ON. Through ArtifactsPlus, she was offering a Beginner's Workshop in fused glass.  I've dabbled in the past in stained glass at the copper foil level and enjoyed that but I've never gone beyond in my interest in glass work.

I've often been tempted by things I've seen on the Internet but classes and workshops have never come my way until now.  This workshop with Marie was a great introduction. 

She explained that fused glass is made by layering or stacking thin sheets of coloured glass to create patterns or images.  A clear sheet of glass is always used as the base layer.  The completed stack of glass is placed into a kiln to be fused by heating it through a programmed series of increases in temperature (ramps) and (soaks) holding the temperature at certain points until the separate pieces of glass begin to fuse together (between 1400ºF and 1500ºF).

Once fused, the glass is cooled at a programmed rate, quickly through 1500ºF to 1000ºF so it doesn't lose its shine and more slowly through the lower temperatures.  A full cycle in the kiln can take 12 to 24 hours depending on the size and thickness of the piece(s) being fired.

We also learned that all glass is not compatible when it comes to fusing.  The glass we were using was coded system 96.  The other major classification is system 90.  Marie uses system 96 exclusively for all her work and is happy with the wide colour range.  System 96 glass when fused at high temperatures and cooled and soaked (held) at 960ºF begins to form a very strong bond (this is what will provide the strength for the piece).   For system 90 glass, this temperature comes at 1000ºF.  This difference in temperature point is why the two types of glass should not be mixed.

We received that technical information in small pieces throughout the day, complete with visual examples that Marie brought along.

When it came to designing our pieces we learned that it was going to be a two stage process.  We were going to pick out a slump mold that was going to determine the size and shape of our piece.  We would be doing a small ring dish and a larger piece.  Colour choices would be up to us. 

Marie showed us a wide range of samples using clear, white and black backgrounds and the effects that other colours had upon them.  We had a wide choice of opaque and transparent sheet glass (system 96) colours to choose from.  We also had glass stringers, which were the thickness of pencil leads; glass noodles, which were like fettuccine noodles; pebbles, which were like blueberry sized blobs and confetti, which were like very thin flakes of glass.

Our base of clear glass had to be cut to the size of our mold. If it was too large, when it was heated it would melt over the side of the mold and stick to it.  It had to be just the right size to sit on top of the mold so that when heated it would slump into the mold and take its shape.  (I forgot to take a picture of my mold).

We used our stained glass cutters to cut out our shapes and prepare our designs after we sketched them on paper.  Because we are layering glass, we had to be careful that we didn't make the edges of the glass too thick or it would spread.  Glass has a memory and it wants to be about 6mm thick.  We wanted our layers of glass to add up to approximately 6mm.  If it was going to be more than 6mm high, we wanted it to be more towards the middle than near the edge since the molds all had a dip in them.

After cutting, the pieces of glass were all cleaned with Windex and lightly tacked in place with a gel glue (just so the pieces won't slide while moving them to the kiln).  They are then fired to fuse all the layers into one piece.

The glass is then removed from the kiln and placed on the mold and fired again to get its shape.  The firing schedule is different because the glass no longer needs to be fused, it just needs to be shaped.

Here is my small project.   It's 3" x 3".  It's going to be a ring dish when it's been fired in its slump mold.  It's in the kiln for its first firing to be fused.

The small black lines are the stringers.

This is 8" x 8" and will be a raised plate shape when it is finished.  I'll post pictures when they are completed.

Here is the small kiln (more jewellery sized)

Here is the large kiln with the class projects in it.

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