ceramic lecture, clay, pottery, handbuilding, stages of clay, teaching
Post on 04-Jul-2015
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Warm Up
In your notebook…Write down 3-4 things that you
already know about clay.Then, write down something that you
want to know about clay.
Ceramics/Pottery/Clay
Stages of Clay
Greenware: clay that has not been fired
• Stage 1: Wet Clay - Flexible clay. Can be formed, modeled, pinched, rolled into slabs or coils at this stage.
• Stage 2: Leather Hard - Second stage. Clay is stiff, but workable. Best stage to join slabs, carve and burnish (smooth using plastic or hard slick surface).
• Stage 3: Bone Dry - All physical water has evaporated. VERY fragile at this point. Ready to be fired.
Warm-UpIn your notebook…Without looking
at your notes, try to name the stages of clay in correct order. Give a brief description of each.
Now, check your notes to see if you are right. Make any corrections
necessary.
Next you will fire the clay
fire: “cooking” clay, this makes the clay very hard. Once the clay is fired it will be in the same shape permanently.
There are clay pots that are 1000s of years old still around today.
kiln: the device used to fire the clay. Similar to how an oven cooks a cake.
Other clay terms
Slip: clay that has been thinned down with water and can be used between pieces to help hold them together (like glue)
Score: scratching the clay to increase the surface area of 2 pieces you are joining together
Here is an example of someone collaring clay on
the wheel. What stage is the clay in?
Answer: Wet
Clay is fired for the first time• This firing is called a bisque firing.
• In a bisque firing the pieces can touch.
• A bisque firing is slower than a glaze firing. This allows time for all of the water to escape.
What comes out of the kiln is called…
• Stage 4: Bisque ware - Clay that has been fired once. All chemical water is gone. Absorbs water and feels rough/chalky.
• Clay has not gone through vitrification, this is why water will pass through it. It is porous.
There are many types of kilns. Some factors that vary from kiln to kiln are…
• How it is heated. Some kilns are heated with electricity, others are heated by gas, or various types of natural materials.
• How it is loaded. Some are loaded from the top (toploaders). Others are loaded from the front (frontloaders). Some are large enough to walk into carrying your pottery (walk-in kilns).
• The type of glaze it produces: Raku, Soda, Salt…
Notice the kiln furniture
Frontloader
Gas Gages
Certain types of kilns create tornadic fire storms inside. The fire will come through any openings including cracks and peep holes.
Electric kiln
The advantages associated with the electric kiln are the following...
• 1. the kiln is easy to fire, requiring little attention.
• 2. the temperature in the kiln is easy to regulate
• 3. It is a clean, non-polluting process
• 4. It produces bright colored glazes
3 handbuilding techniques
• Pinch pot-push thumb into a ball of clay and pinch into desired shape
• Slab-roll clay out and cut out pieces. Attach pieces together by scoring, slipping, and smoothing over the seem
• Coil-roll out snake like pieces of clay and attach them one on top of another
The Second firing is
• the glaze firing
• A piece of pottery may be fired more than 2 times (it will not damage the clay), but usually 2 times is enough.
• Stage 5: Glazeware-pottery that has been fired with glaze on it. This is the last stage.
Glaze
• a continuous layer of glass or glassy crystals fused to the surface of fired clay.
• provides a surface impervious to liquids and easy to clean.
• can be smooth or textured, shiny or dull
More on glaze…
• matte- not shiny, dull• gloss- shiny• Glazes do not mix like paint. Yellow and
Blue do not necessarily make green. • Glaze is made up of glass and clay
molecules along with various chemicals which produce color.
• Glaze colors are produced by the chemicals’ reaction to heat.
Functional…describes pottery that has been designed and produced with a use in mind, “everyday ware” or the term UTILITARIAN might be used to describe the same. Usually very simple or basic.
Without looking at your notes, Write down as many
things as you can remember about sculpting utilitarian
(usable) objects.
Utilitarian Work
Plates, saucers, mugs, casserole dishes, pencil holders, hotpads, etc.
If you plan to eat from the work…
• be sure to use a lead free glaze
• don’t use paint
• thoroughly coat all surfaces with glaze
• avoid “nooks and crannies” when sculpting
Dryfoot…to clean the bottom of any piece of glazed ware before it is fired so that it is free of glaze. Wax, either heated or liquid resist, is frequently used.
Warm Upsand Reviews
Warm-Up
Write down as much information about this kiln as you can. How is it fueled?
How do you “close the door”?
What is the man about to do?
How can you tell how hot it is in this kiln?
Is this the same type of kiln we have?
Draw 3 ideas for the cup you would like to make out of clay.
Warm Up
Answer in your notebook:
What are the stages of clay?
Which of the stages are greenware?
Warm-Up: Answer in your notebook
What are the 3 handbuilding techniques?
Which technique(s) are you using in your work?
How could you use a different technique to complete your project?
Look back at your warm up from Monday. What have you learned about clay this week?
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