Unit 2: Coil-Building

Lesson 1: Narratives on Clay

Ancient Greek Ceramics:Grain and oil were stored in large jars called pithoi. These were built using coil-building.

Greek potters created several types of urns, like oil flasks (amphorae), wine bowls (kylix), and pitchers (oinochoe).

The Greeks were the first to paint stories on pots.

Ancient Greek Ceramics

The Greeks painted scenes featuring the human figure as early as 2900 B.C.Art that represents the human figure is called figurative.

They decorated their forms with monsters, heroes, and mythological figures mostly in profile view.

In early work, they painted black figures onto red clay.

In later work, they used black slip to paint their background. Then they carved out the figures.

Ancient Greek Ceramics

Moche Pottery

About 500 years after the Greeks first developed black-figure technique

The Moche (50 800 A.D.) were located in northern Peru

Recorded their beliefs and their history on their pots

Moche Pottery

They had no writing system

Scholars consider their ceramics a library of information because they recorded such detail on their work

The Moche applied fine lines of slip to create their imagery (slip painting).

They always portrayed figures in profile.

They are also known for their stirrup vessels.

Moche Ceramics

Mayan Ceramics

Located north of the Moche, in modern-day Belize, Guatemala, and southern Mexico

The Mayan Classical Period (250 850 A.D.)

Their multicoloured ceramics were built using coil and slab techniques.

Mayan Ceramics

They also used slip painting.

They portrayed religious themes, rituals, and history.

Like the Moche, their figures were always in profile.

In contrast to the Greeks and the Moche, the Maya developed several colours for their slip.

Mayan
Ceramics

Lesson 2: Jomon Ceramics

The first people to settle on Japan's chain of islands

Although little is known about them, it is thought that they thrived with plenty of food and low risk of invasion from 9,000 300 B.C.

jomon - cord patterned

Jomon Ceramics

The Jomon created storage pots which they elaborately decorated with surface coils.

Many Jomon designs also included impressions, incising, and subtle animal imagery.

Jomon pottery stands out because the Jomon people were hunter-gatherers. Historically, storage vessels weren't produced until the people settled into a farming lifestyle.

With ample food and a peaceful lifestyle, perhaps they were simply enjoying the luxury of creating artistic objects.

Lesson 3: Kilns & Firing

Kiln a structure designed to fire clay

Electric kilns fuelled by electricity. Has evenly spaced heating elements/coils that surround the firing chamber.

Walls are made of soft, insulating brick wrapped in a metal casing

Safer and cleaner than most other firing methods

Kilns & Firing

Gas Kilns fuelled by natural gas; it is either connected to municipal utilities or tanks (like propane tanks for a barbeque)

Same basic construction: soft bricks to insulte + metal casing

Kilns & Firing

DURING A FIRING:Adequate ventilation is always necessary. Unhealthy gases such as sulfur and carbon monoxide are released during firings.

Work must never touch the kiln elements, as the coils can be damaged.

Stages of Firing

1) Bisque Firing- the first time clay is firedBisque firing changes the chemical structure of greenware so it becomes permanent

Temperature is low enough to allow the clay to stay porous (able to absorb liquid, like glaze)

Stages of Firing

2) Glaze Firing after the piece has been bisque fired and glaze has been appliedThis goes to a higher temperature than the bisque in order to melt the oxides, underglazes, and glazes

Because melting occurs, pieces cannot touch each other, the kiln walls, or kiln furniture.

Kiln Wash a protective substance that is put on the kiln shelves before every glaze firing

Variables in Firing

1) Atmosphere (the mixture of gases in the kiln)Oxidizing atmosphere when oxygen is present in the firing chamber; electric kilns usually have this atmosphere

Reduction atmosphere when oxygen is removed from the firing chamber; this changes the resultant colours; wood or gas kilns are usually used for reduction firing.

Variables in Firing

2) Temperature measured by a pyrometer inside the kiln

SUPER LOW TEMPERATUREDehydration begins. Cone 022

Cone 021

...

Cone 09

Bisque firing1730 F/ 943 CCone 08

Cone 07

LOW: Earthenware glaze firing1823 F/ 995 CCone 06

Cone 04

Cone 03

Cone 02

Cone 01

Cone 1

Cone 2

........

MID: Stoneware glaze firing (2225 F/ 1218 C)Cone 6

......

Cone 10

HOTTEST:Porcelain glaze firing 2359 F/ 1292 CCone 11

The higher you fire, the more stress is put on the clay.

Additional Firing Techniques

Group Ambassador Activity:6 groups (6 different firing techniques)

Each group will receive information about one firing technique.

Your group will send all but one member to visit other groups to get their information.

After your ambassadors have gotten information, you will reform your original groups and combine all your facts.

Additional Firing Techniques

1) Bonfire - the most ancient firing system. This is a fast process, which can cause the greenware to break. Using grog, sand, or other additives can help to strengthen the clay against thermal shock. The pots are warmed by burning straw inside them. Then the work is left to dry even further on the embers of a wood fire. Lastly, the work is piled on a bed of sticks, and covered with shards of broken pottery and more firewood. The work that emerges from the firing is black from the carbon in the smoke. Bonfire kilns generally reach earthenware temperatures around 1290 F/700 C.

Additional Firing Techniques

2) Pit Firing - similar to bonfiring, but the pots are put in a pit that is covered with a metal lid. Because the earth walls of the pit insulate the firing chamber, the kiln temperature is more even, higher temperatures can be achieved, and the kiln cools down more slowly. Therefore, there is less breakage.

3) Sawdust Firing - sawdust can be used as fuel in pit firing or in a metal trash can. If firing in a trash can, holes must be drilled in the bottom, sides, and lid of the can to provide enough air flow. Newspaper is used as additional fuel.

Additional Firing Techniques

4) Wood Firing - there are many specially designed chambers for wood firing. Eastern designs build multi-chambered kilns into hillsides. Western designs usually have a single chamber with a chimney to draw the heat upwards. The wood is burned in a space below the chamber, so the work is protected from direct contact with the flames. This is a demanding firing technique, as the potter must constantly watch the fire for at least a day. 5) Saggar Firing - a saggar is a fire-resistant container. It can be made of brick, a large pot, or other fireproof material. This technique was originally developed by the Chinese during the Song dynasty (960 - 1279 A.D.) to shield porcelain from the ashes in wood firing. Today, potters use saggars for the opposite purpose. They put combustibles (like plant matter, wire, and paper) in the saggars with their work in order to achieve different effects.

Additional Firing Techniques

6) Raku - previously bisqued and glazed pieces are fired quickly to a low heat that is enough to melt the glaze. Once the glaze matures to a glassy surface, the potter uses special equipment to pull the piece from the hot kiln, and places it in a container full of organic materials (like leaves, paper, wood shavings). The potter places a lid on the container to smother any flames and create a reduction atmosphere. The carbon from the smoke permanently colours the clay black. Special glaze effects can be achieved with this method, like crackling and metallic flashes.

Reflection: Unit 2

1) Do you think you were successful in using coil-building? Explain.

2) Do you think you were successful in decorating your vessel? Explain.

3) What did you like or dislike about this project?

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