Pottery

Mycenaean vases. Kanellopoulos Museum at Athens.

Pottery is the process and the products of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures (600–1600 °C) to give them a hard and durable form.

Uses

Pottery is widely used for cookware, storage, and tooling. Art pieces may also be formed with clay.

Materials needed

• Clay, or other pottery medium
• Temper, a non-plastic material such as sand or grog (ground-up pottery, usually from broken or failed firings)
• A source of heat, in the form of fuel (wood, coal or gas) or electricity through a resistance
• Optionally: a kiln for containing the heat and achieving higher temperatures
• Optionally: a pottery wheel and ceramic glaze

Identify and extract clay

Where to find clay?

Wetlands: riverbanks, lakeshores, or clayey areas (sticky soil when it rains, cracks when dry).

Geological layers: Cliffs, quarries, or grey/yellow soils (avoid sandy soils).

Simple test: Take a sample, wet it and mix. Make into a coil and twist it around your finger. If it does not crack, it is clay.

Extraction:

Dig to a depth of 30-50 cm (1-2 elbow to fist length) to avoid impurities.

Recover 5-10 kg for a first test.

Clean and prepare clay

Remove impurities

1. Work the clay with water and remove stones and roots.

Decanting

1. Mix the clay with a lot of water in a bucket or basin.
2. Heavy particles (sand) sink to the bottom, while the clay remains in suspension.
3. Collect the cloudy water (clay) and discard the sandy deposit.
4. Leave for 24 hours: the clay will slowly set. Discard the excess water.
5. Spread the mud on a cloth or plate to evaporate remaining water.
6. When the clay is malleable (modeling clay consistency), it's ready.

Tempering

The clay will often require being mixed with temper, roughly 4:1 clay to temper ratio (1 cup of sand for 4 cup of clay).

On the other hand, some clays require no to little temper, it will depend on the nature of the clay that is used.

Mixing clay and temper is easier when the clay is powdered but temper can also be worked in the malleable clay.

Crafting instructions

Pottery can be created using many different methods. Here will be covered: Pinch, coil, and turned pottery. After the pottery is formed, the process is the same.

Pinch Pottery

1. With a ball of clay or other pottery medium, gradually pinch and shape into desired form.

Coil Pottery

1. Begin with a flat base of clay, serving as the bottom of the pottery.
2. Roll a coil of clay and fuse it on top of the base, tracing the perimeter. Watered down clay, called slip, is used.
3. Subsequent coils are fused to the layer below, building a vessel to desired shape.
4. Coils may be smoothed over to finalized its form.

Turned pottery

While turning pottery, it is important that hands are always kept wet to lubricate the clay.

1. On a pottery wheel, secure a lump of clay.
2. While the wheel turns and with wet hands, cone the clay up and down to eliminate air bubbles and align the molecules of clay.
3. Form a well in the clay until the desired thickness of the base is achieved.
4. Pull the clay outwards to turn the well into the flat base.
5. The walls can gradually be pulled up, having care to ensure the clay runs concentric to the wheel.
6. After the shape is achieved, excess water is removed from inside and out to prevent disintegration.
7. Removed from the wheel to dry.
8. Once the clay has dried to the point to leather-hardness (firm, and not sticky) it may be trimmed.

Firing to ceramic

When clay is worked into pottery, it is still wet and will dissolve in water. To make it more durable, it must be fired into ceramic.

1. Allow the pottery to slowly dry out completely, covered with a damp cloth. Too rapid of drying may cause warping or cracking.
2. The bone-dry pottery can now be bisque-fired at 850–1000°C (1560–1830°F) for about 8 to 14 hours depending on size and shape. This can be done in a hole in the ground or in a kiln.
3. The pottery will now be ceramic, but will be porous and may not hold water. The pottery can now be glazed and fired again at 1040–1100°C (1900–2010°F) for earthenware glaze or 1200–1300°C (2190–2370°F) for stoneware glaze for about 6 to 10 hours depending on size and shape.

Ceramic pottery can also be made non porous by using wax, such as beeswax. Apply when the pottery is still warm from the firing (not too hot or it may catch fire) and as the wax melts it will be absorbed by the ceramic, making it watertight.

Dependencies

• Ceramic
• Clay
• Heat
  • Pottery

See also

• Fuel
• Kiln

External links

• Clay pots suitable for preparing any food in the forest. - Pre Technology, 26 February 2021, YouTube

This article uses material from the Wikipedia article Pottery, which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors).