Ceramics

What is Ceramics?

• Ceramics is the art of making objects out of Clay

ClayThere are different types of clay

Earthenware: This is a low-fire clay that is gray when wet and is white once fired

–This is what we will be using

Seven Stages of Clay

WetLeatherhardGreenware

First FireBisqueGlaze

Second Fire

Wet Clay• What do we notice about the clay at this

stage? Describe.Try to build a tall skinny tower that stands straight up

• At this stage the clay is soft and flexible because it is about 75% percent water

• We do not want to build with clay at this stage because it is too soft.

• There is no strength or structure to this clay (falls over and collapses, gets stuck to things)

Leatherhard ClayNow that you’ve played with the clay more,

try making that skinny tower stand straight up again

•After clay has been worked with and exposed to the air the water begins to evaporate, now it is only 50-30% water

This is the perfect stage for building.

The clay has structure and strength but is still workable for change. We love this stage and want our project to stay in this

stage until we are finished working on it.

Greenware Clay• Greenware clay is clay that

has been exposed to the air long enough for all the water to evaporate from the project. It is made of 0% water. In other words, it’s dry.

-Once you have completed your project you will leave it unwrapped so it can enter the greenware stage.

-Clay at this stage will hold its shape but is very fragile.What you have made is not just clay anymore, it is now a ceramic piece.

*This is the last stage in which we can recycle the clay

First Fire• Once clay has completely dried out and has

entered the greenware it is put into the kiln and fired.

–A kiln is a ceramics oven.

• Firing is when the temperature inside the kiln is brought up to about 1900 degrees (almost 4x hotter than a kitchen oven)This is a low fire temperature; high fire is about 2400 degrees

Bisque

– This is clay that is permanently hard. There is no going back to workable clay after it has been bisqued.

– The clay is now strong, but remember it’s still ceramic- be careful!

• Clay that has been through one firing in the kiln is called bisqued

Glazing• Glazing is when you paint a thin layer of

minerals and glass onto a bisqued ceramic piece. This will give your piece color and gloss.– Glazes look different when the come out of the jar then

they do in the end. Look up the glaze on the tile to know what you’re using.

– You can glaze the inside and outside of projects but not the bottom. If glazes are on the bottom they melt and glue themselves to the kiln.

Second Fire• After the glaze is painted on your ceramic

piece it will go back into the kiln for a second fire.– The kiln heats up to only about 1700 degrees this

time.– This changes the glazes to their final look.

Building with Clay

Techniques

• There are four different techniques you can use when building with clay.

–Pinch Method–Coil Building–Slab Building–Throwing/Pottery Wheel

Slab Building

• To slab build you must roll out a piece of clay so that it has even thickness throughout

• Then you score and slip the different slab pieces where you want to attach them

• Coils should be rolled out and smoothed into joined corners for added support

Recycling Clay

Clay scraps and unworkable dried out clay can be brought back to working clay by recycling it

Clay is placed in buckets and left to soak in water

Once soaked it can be wedged to new wet working clay

Even if clay has entered the GREENware stage, it can be recycled