Types of Pottery
Earthenware
Earthenware is lightly fired, readily absorbs water if not glazed, and does not allow light to pass through it. Coarse earthenware is made from clay and grog (ground up fired pots). It is the colour of the clay as it is dug from the ground - buff, brown and red. A modern earthenware recipe would be: 25% ball clay, 25% china clay, 35% flint, 15% china stone. The first or biscuit firing temperature is 1100 C - 1150 C, glost firing 1050 C - 1100 C.
Stoneware
Stoneware is extremely strong and will not absorb water. It is fired at higher temperatures than earthenware so that the body vitrifies (ingredients melt and fuse together). It will not allow light to pass through it. Dark coloured stoneware is made from buff, brown and red clays without and added ingredients. Light coloured stoneware was made from the 18th century from the following ingredients : 25% ball clay, 25% china clay, 35% flint, 15% china stone. Firing: 1200 C- 1300 C. There is usually only one firing, but if a glost firing is needed it will be at about 1050 C.
Porcelain :
Hardpaste porcelain
This type of porcelain often has a grey appearance and is extremely hard. The ingredients melt and fuse into a dense strong body . It will allow bright light to pass through it. Colours lie on top of the glaze. Hardpaste porcelain recipe: 50% china clay, 30% china stone, 20% flint. Firing: Biscuit temperature 900 C - 1000 C. Glost firing 1350 C - 1400 C.
Softpaste porcelain
Softpaste porcelain is soft and the body is granular since the ingredients do not melt together. The glaze is clear and thick and sometimes gathers into pools. The enamel colours sink into the glaze. Glassy porcelain has no standard recipe but the body is made from - Glass, China stone, other ingredients. Firing temperatures: biscuit 1200 C - 1300 C, glost 1050 C - 1150 C
Bone China
Bone china is extremely hard, intensely white and will allow light to pass through it. Strength is provided by the fusion of body ingredients during firing. This unique English pottery body is made from the following: 50% animal bone, 25% china clay, 25% china stone. First or biscuit firing 1200 C - 1300 C. Second or glost firing 1050 C - 1100 C.
