My friend Suzannah made this. We have a kiln to fire our clay in and we also have glazes. Suzannah's brother made the fruit bowl.
By Suzie
By Mark.
Some fun clay facts for the interested ...
Unfired air dried clay is known as "green ware". A green ware piece can be melted back down to being a glob of clay, simply by adding water. Before a piece can be put into the kiln, it must be thoroughly dried. This can take up to a week depending on atmospheric conditions and the thickness of the clay.
Once dry the clay is fired at a temperature of 1050 degrees for stoneware. This is the biscuit or bisque firing and is slow. The temperature must be brought up slowly to avoid breaking the clay by thermal shock. The following temperature points are critical.
- 100 oC 212 oF - water turns to steam
- 225 oC 440 oF - cristobalite (a form of silicon oxide) rapidly expands
- 270 oC 517 oF - carbon burns
- 573 oC 1050 oF - quartz (another form of silicon oxide) rapidly expands
- 900 oC 1652 oF - the clay isnow strong enough to take normal handling
Once you get above 600 oC, the clay has been transformed and will no longer melt by just adding water. The chemically combined water is driven off at that temperature.
After a bisque firing, the piece is now ready to glaze. Glaze firing is usually much more straight forward than bisque firing. Since the work has already been fired, there is no chance of it blowing up in the kiln. The glaze firing is simply intended to bring the glaze to a temperature when it will 'flux' or melt, forming a permanent coating. This means that you do not have to start a glaze firing slowly. The slide show below shows our work in the various stages - air drying, glazed, fired.
PS. I changed the template to one called 'soap' - slightly different to the previous one. I don't know why the profile picture suddenly changed to that. I think it only happens when you change thhe template the second time.
Bye!
Beth~
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