Thursday, March 4, 2010

4th Grade Clay Projects...

We completed building the clay coil construction projects today and now they are drying in preparation for their first firing in the kiln.

There were no guidelines on what to build, other than the project must be built with coils and use scoring and slip to secure the parts to each other. Smoothing the sides to erase the coils was optional. Many students built vases, cups, and bowls. A few even built plates or baskets.

A KILN is a large and extremely high temperature oven. The clay projects are useless at the moment, because they can be broken very easily, or melted down in water to become mud again. Cooking them at high kiln temperatures is called FIRING the clay. The clay doesn't really catch fire, though. This first firing is called a BISQUE fire. It will transform the 'mud' into 'stone'. That will make the project much more durable. For this bisque transformation, the kiln will reach temperatures around 1800* F.

Next week.... GLAZING!
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