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Bell Ringer March 4, 2015

Bell Ringer March 4, 2015. What is clay?. Comprehensive Art Mrs. Brown. Introduction to Ceramics. What is Clay?. Clay is . . . . . .a fine mixture of decomposed igneous rock materials and organic matter. Clay is continuously being formed.

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Bell Ringer March 4, 2015

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  1. Bell Ringer March 4, 2015 What is clay?

  2. Comprehensive Art Mrs. Brown Introduction to Ceramics

  3. What is Clay? Clay is . . . . . .a fine mixture of decomposed igneous rock materials and organic matter. • Clay is continuously being formed.

  4. Over time, exposure to the elements cause the materials to break down into smaller and smaller pieces: Weathering Boulders Rocks Pebbles Fine grain = materials that make up clay.

  5. Weathering Processes:

  6. What is Ceramics? Objects made from any type of clay that is fired with the aid of heat

  7. History of Ceramics It is hypothesized that ceramics came about when humans 1st learned to control fire. Old methods and concepts are still used today.

  8. Historical Ceramic Origins • Anthropologists use Stone Age clues to piece together a variety of possible theories of ceramic’s origin

  9. Functional Purposes:Storage Vessel Examples • Greece 1600 B.C • Some jars as tall as 6 ft • Created using the coil method

  10. Communication & Documentation: Cuneiform Script • Early system of writing in Mesopotamia • Stylus pressed into clay tablets • Record-keeping of laws, historical events, & harvests

  11. Cylinder Seal Form of signature, or identification on important documents. Hunting Scene 2250-2150 BCE, Mesopotamia

  12. Spiritual & Religious Purposes: Pots were widely used as funerary objects in prehistoric burial grounds Contained food to accompany dead on journey to the afterlife Infants and small children Ceramic figurines and animals to protect the deceased.

  13. Terracotta Warriors • Form of funerary art - buried with the First Emperor of Qin (He was the first emperor of China in 221 BCE.) • Their purpose was to help him rule in the afterlife. • Architects are currently still excavating

  14. 6 Steps to Using Clay • Early Preparation (Levigation) • Forming Clay (5 major methods) • Drying Clay • Decorating Clay • Glazing • Firing These two stages (5 & 6) can happen in reverse order as well.

  15. Step 1: Early Clay Preparation • Early potters dug their raw material out of the ground, and it often contained impurities such as pebbles or plant matter. • To remove these, potters would dry the clay in the sun, crush it into smaller lumps, and pick out the unwanted material. • Then, they rehydrate the dry clay to make it workable. • This method was fine for making a few pots, but it was difficult and time-consuming. ** The clay that Mrs. Brown gives you has already been through this early clay preparation process.

  16. Modern Clay Preparation • Potters discovered it was much easier and faster to separate impurities by adding water to the clay and then pouring the liquid clay (slip) from one container to another. • This process is known as decanting. Decanting causes the coarser materials to settle on the bottom. • Another traditional method for removing impurities is known as Levigation.

  17. Step 2: Forming Clay The earliest and simplest methods are still used today. Four Basic Hand Building Techniques: • Pinch Method (oldest method) • Coil Method • Slab Method • Molding Method

  18. Hand Building: Process of forming pieces using hands without the use of a potter’s wheel; 30,000 years old.

  19. Pinch Method • Is when clay is pulled and pinched in order to shape an object with fingers. • It is the oldest form of ceramic hand building.

  20. Pinch Pot

  21. Pinch Method:

  22. Two Pinch Pots Combined to create a hollow form:

  23. Coil Method Created through long ropes/coils of clay that are of equal thicknesses are used to build a ceramic object

  24. Coil

  25. Coil

  26. Slab Method • A method of rolling out clay flat to an equal thickness. • Slabs can be cut into shapes and used to construct ceramic objects.

  27. Slab Method

  28. Slab Method

  29. Throwing: A method of forming clay in which the sculptor uses a pottery wheel. Throwing is NOT a technique of hand-building.

  30. Potter’s Wheel : A machine that forms pottery using a wheel

  31. Step 3: Drying Clay • Potters must know how to control the rate at which clay dries. Clay shrinks as it dries and, if it shrinks too rapidly, it can crack. • Clay that has dried to this point is in the leather-hard stage; when pressure is applied to the clay, the form will not easily distort. • See the following Stages of Clay.

  32. 6 Stages of Clay • Slip • Wet/Plastic • Leatherhard • Bone-Dry ~Firing~ 5. Bisque (Bisqueware) ~Firing~ 6. Glazeware (Glazenware) Stages 2 – 4 are also known as Greenware.

  33. 6 Stages of Clay • Slip: Liquid clay; “glue” required to attach two pieces of clay together.

  34. 6 Stages of Clay Con’t • Wet: Plastic clay; workable; easily manipulated. ** IDEAL * When Mrs. Brown gives you clay out of the bag it is in this stage.

  35. 6 Stages of Clay Con’t 3. Leather Hard: Clay is stiff but still damp; firm -maintains form and can be smoothed, carved, and added to. *not easily distorted, but can still be carved.

  36. 6 Stages of Clay Con’t: 4. Bone-dry: Water has evaporated from the clay; form is brittle and ready to be fired. ** Clay becomes lighter in color

  37. 6 Stages of Clay Con’t • Bisque (Bisqueware): fired once; ready to be glazed then fired a second time.

  38. 6 Stages of Clay Con’t 6. Glazeware: Objects that have been fired a second time after glaze has been applied.

  39. Clay may be recycled through the Bone Dry stage by simply rehydrating it. R*E*C*Y*C*L*E : **Once clay has been fired it becomes permanent – it can no longer be recycled.

  40. Step 4: Decorating Clay • Impressing uses an object to press or stamp a design into the clay. • Combing marks the surface of the clay with uniform lines. • Burnishinginvolves rubbing and polishing the surface with a smooth stone or piece of hard wood.

  41. Incising – Carving or cutting into the clay surface with a tool.

  42. Step 5: Glazing • Glaze: A coating of liquid glass that is applied to a clay surface that melts together and forms a decorative and protective surface.

  43. Glaze also makes your ceramic piece: • Colorful • Food Safe (check glaze label.) • Water Proof

  44. Step 6: Firing The earliest pottery was fired in open fires.

  45. Firing Methods The main methods of firing clay are: Open Firing: in which the vessels and fuels are set together. Kiln Firing: in which the vessels and fuels are separated.

  46. The Kiln: • Chamber for firing your clay. • Clay MUST be Bone Dry to fire. • You must fire your clay for it to become permanent.

  47. Kiln (Con’t) • A kiln can reach temperatures of 2,500 degrees F and higher. • Your oven at home possibly reaches 500 degrees - at the most.

  48. The Kiln

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