When you look at a handmade, kiln worked piece of glass, notice the thickness. Did you know that in nature, glass heated to molten temperatures wants to be a certain thickness?
Firstly, the term kiln worked means it has placed in a kiln and heated anywhere from 1220 to 1550 degrees F. That's hot!
When in the kiln, if the temperature goes to what is called full fuse, this means the glass becomes molten hot. It wants to move and become a certain thickness - 1/4" or 6mm. Glass will actually shrink in width or expand in width to accommodate this characteristic if it is not already the magic 6mm.
Why does this happen? Two properties in nature effect glass when molten hot - surface tension and gravity. These two things 'fight' each other until an equilibrium is found and that just so happens to be 6mm.
This magic 6mm can be altered by creating barriers inside the kiln that keep it from expanding further, shrinking is another story all together.
So the next time you look at a piece of kiln worked glass (maybe at the New Hope Arts Festivals' Eye Candy Glass Art booth Sept 27?), you'll notice the thickness and know why.