Intro to the Little, Brown Essential Handbook, 7th Ed, CDargan Fall 13
Ceramics Intro (7th)
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Transcript of Ceramics Intro (7th)
Ceramics
What is Ceramics?
• Ceramics is the art of making objects out of Clay– Objects or sculptures are built out of clay and then
“fired” in a kiln, a special ceramics oven. Then the object can be glazed and fired again to add color or gloss to the piece.
ClayThere are many 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?–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
Leatherhard Clay
• 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 stage • Greenware projects will be put in the kiln and
fired.
A kiln is a ceramics oven.• Firing is when the temperature inside the oven
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.– This changes the clay to bisqued clay.
Bisque
• Clay that has been through one firing in the kiln is called bisqued clay.– 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!
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 different techniques you can use when building with clay.
–Pinch Method–Coil Building–Slab Building–Throwing/Pottery Wheel
Pinch Method
• This is when you pinch and pull the sides of clay to shape it as you want
http://youtu.be/gIj8oDluZtQ
Coil Building• Coil building is rolling out clay into coils, and
then attaching them together• Rolling out rope like pieces of clay with your
hands, size of coil depends on size of our project
Then you stack them to build
Attaching Coils• Can’t just stack, you need to slip and score
Scratch it up, add slip, stack on top each other
• You scratch it and then slip to make sure they all hold together the right way because when clay dries it shrinks 11% and you will have gaps if you don’t slip and score
• Then you need to smooth at least one side of the clay, inside or outside our both
• When you slide your finger over the coils and smooth it together you’re making it stronger and getting rid of any gaps. If your project has gaps then water will go through it. If you want it to hold water or be functional like that then your project was not a success if you have gaps. Which means it is not functional for what you intended it for.
http://youtu.be/PgYJvbQgb40
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
http://youtu.be/Dn55cIO8D2E
Throwing• Throwing is the act of
creating ceramic pieces on a pottery wheel
• A pottery wheel is a flat spinning disk used to make ceramic work
http://youtu.be/6svHOgZGwnU
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