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Due to its porosity, earthenware is susceptible to moisture and creates problems including cracks, breaks and mold growth. Porcelain and stoneware are fired at the highest temperatures between 1200–1400°C or 2192–2552°F. Porcelain clay mixtures are fired to create a non-porous and very hard surface.
Staple repair is another technique used to repair broken ceramic pieces, [26] where small holes are drilled on either side of a crack and metal staples are bent to hold the pieces together. [27] Staple repair was used in Europe (in ancient Greece, England and Russia among others), South America, [ 28 ] and China as a repair technique for ...
Pottery fracture results from stress within a ceramic body due to thermal expansion and contraction, shrinkage, and other forces. Poor drying or uneven compression and alignment of particles can result in low strength. Cracking may appear in greenware as well as each stage of the firing including bisqueware and glazed ware. [1]
Crazing is a spider web pattern of cracks penetrating the glaze. It is caused by tensile stresses greater than the glaze is able to withstand. [1] [2] Common reasons for such stresses are: a mismatch between the thermal expansions of glaze and body; from moisture expansion of the body; and in the case of glazed tiles fixed to a wall, movement of the wall or of the bonding material used to fix ...
However, using less fiber in paper clay on the potters wheel is recommended, particularly if the leather hard work is to be trimmed on the wheel. Paper clay can be made from left over throwing slip from wheel throwing. It is widely used by potters to repair cracks in dry, conventional clay, as well as dry paper clay.
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A common example is a fig leaf being painted over a nude figure. Overly aggressive cleaning with acid can also cause damage. Acid cleaning is meant to remove insoluble salts and minerals from the surface of archaeological ceramics. Pottery that has been improperly cleaned and damaged by acid may have pitted, cracked, powdery, or flaking ...
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