What is Clay?
Clay is a special kind of earth which is made by the decomposition of rocks through the action of weathering.
What does that mean?
Well basically, over time, bits of earth are carried from one place to another by water and deposited in areas where the water slows down to a trickle.
(Have you ever gone digging by the water's edge only to grab a handful of muck? Well that muck is clay.) As the bits of earth travel with the water, they pick up all sorts of stuff and by the time we pick up a box of clay from the pottery store, the muck has been collected and prepared for us to use. All of the tiny rocks and lumps have been removed and some additional materials, like sand are sometimes added to create the perfect workable clay.
What Else?
Clay can be found anywhere but it is only useful for pottery if it has good "plasticity." You can test this by seeing how stretchy a piece of clay is. If you can take a piece of clay, roll it into a coil and bend it into a ring without cracking and falling apart, chances are it will make good pots and sculptures.
Natural clay that we find outside usually needs to be cleaned and refined before it can be used. Any tiny rocks and lumps are removed and some additional materials, like sand are sometimes added to create the perfect workable clay that we buy from the pottery supply house.
Working With Clay:
Clay artists throughout the ages have invented many ways to shape things out of clay.
PINCH - Use your fingers to pinch and poke a single lump of clay into any shape.
SLAB - Roll the clay into flat sheets (like a pie crust) to cut apart and assemble.
COIL - Roll out long snakes of clay and twist them into coils and shapes.
WHEEL - Spin clay on a potter's wheel to form pots and vases.
Some Tools to Use When Working with Clay:
- Your fingers
- Rolling pins and canvas
- Popsicle sticks and toothpicks
- Cookie cutters
- Plastic bags
- A clay cutter (wire)
- Sponges
- Various carving tools, nuts and bolts, old toothbrushes and anything else you can get your hands on that will create texture in the clay
SOME........clay definitions you need to know before making a pinch pot:
Earthenware: This is the type of clay often used in schools. It comes in white or red and it is fired to a temperature of approximately 1000 degrees C. or 1830 degrees F.
Slip: This is liquid clay ... clay with a lot of water added to it. It is sometimes used as a sort of glue to hold clay pieces together. You need to use slip to "fasten" pieces of clay together so that they don't fall apart in the kiln.
You see, clay shrinks as it dries so if you haven't made sure that your clay pieces are firmly attached, they will separate in the kiln. It isn't enough to simply "pile" one piece of clay on the next. Use watered down clay as your glue.
Shrinkage: As clay begins to dry the water in the clay body begins to evaporate. This will cause the clay to slightly shrink as it dries.
Important Tips for Success!!!
- The rule of thumb - this means your clay should never be thicker than the width of your thumb. A good thickness for a pinch pot is the width of your pinkie finger. Use your fingers as measuring tools when making your pot!
- Work quickly and purposefully with clay, it tends to have a memory and can give out and get exhausted if you work with it too much or for too long.
- Smooth cracks as you go along.
- Keep the clay moist but avoid using a lot of water. This can create a slime on your clay body which leads to cracking and falling apart.
When you have completed your learning guide, have your teacher sign it so you can move on to the next step.
Information Sources:
Kinder Art - http://www.kinderart.com/sculpture/clay.shtml
Photo Sources:
https://upload.wikimedia.org/wikipedia/commons/3/36/Clay_Mixing_for_Pottery.jpg
http://cottonridgehomeschool.com/wp-content/uploads/2012/10/Laguna-Red-Calico-Clay.jpg
http://www.chinacrushing.com/blog/wp-content/uploads/2012/01/Clay1.jpg
https://cmdcapstone.files.wordpress.com/2015/04/tumblr_nlzqtqhldc1r5mafso1_1280.jpg
http://www.osartistsco-op.com/pixhow/pinch02.jpg
