Salt glaze

To produce this glaze, salt is allowed to react with the pot surface made of clay. It is done by throwing salt on to the pot surface during the firing of the pot. Salt corrodes the surface, and the corroded layer is the salt glaze. The process is actually high-temperature soda corrosion of the fired clay. 

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Crete piping systems can be lined with special salt-glazed vitrified-clay liner plates, joined with a die-cast aspnalt joint. Concrete pressure pipe is competitive with cement-lined ductile iron for underground plant water systems. 

Salz>glasur, /. salt glaze, -grube, /. salt pit, salt mine. 

Flexadrain Joint, developed by the National Salt Glazed Pipe Man. Assn, and British Ceramic Research Assn. 

The common potter s clays in England are found in layers or strata lying over each other, each stratum possessing some distinctive property which fits it for a peculiar purpose. That-which is called the sandy stiff, or ball-clay, is the upper layer, and from the considerable quantity of silica it contaios is used for making salt-glazed ware. On analysis this clay, dried at 212°, will be found to yield —-... 

Vauxhall, 74-00 27-04 2-00 0-60 0-17 1-00 0-13 100-00 salt glaze. Fine whitish body, well moulded, with a porous external surfaoe, salt glazed. 

Figure 6. Bivariate plot of lead oxide and sodium oxide base-10 logged concentrations projecting high sodium and salt glazes against the remaining technological groups. Ellipses represent 90% confidence interval for group...

The interaction of silica and sodium chloride, characteristic of such processes as salt-glazing, coking salty coals, and chloridizing roasts, has been investigated up to 1000° C. by Clews and Thompson.11 There are three distinct reactions corresponding with the equations... 

The stoneware surface is usually provided with the so-callcd salt glaze which is formed on the surface spontaneously, as a result of sodium chloride being introduced into the kiln at the end of firing. In the presence of water vapour, sodium chloride vapour reacts with Si02 and the other components producing a smooth silicate layer. Feldspar glazes represent the other alternative. 

Acid-resistant stoneware is given a salt glaze and is resistant to all acids except hydrofluoric acid. The acid resistance can be increased by adding zirconium oxide or phosphates, the alkali resistance by adding barium oxide, magnesium oxide or chromium oxide. 

The most important fireclay-producing area is between Tam-worth and Nuneaton (the so-called Nuneaton clay). The latter is not very refractory but is used for making building-bricks, salt-glazed pipes, tiles and chemical stoneware. 

Fireclays of widely varying composition occur, and are concentrated in the Leeds and Halifax districts. Many of them provide high-quality refractory bricks others, which are less refractory, are used for making salt-glazed ware and drain-pipes. Somewhat less refractory fireclays of a more siliceous nature are obtained from the Huddersfield and Sheffield districts. The pot clay seam in the Stannington area of South Yorkshire, a Carboniferous clay mined by opencast methods, is used for casting pit ware and grog production. 

Some fireclay deposits are worked in Co. Tyrone they are mostly of inferior grade and unsuitable for refractory products, but some are said to be very suitable for the manufacture of salt-glazed pipes. 

German stoneware salt glazing English slipware... 

Vitrification Phase separation in glass Pottery salt glazes... 

Surfaces shall be smooth (without scratches) and edges shall not be broken or damaged. Salt glazed surfaces are preferred. 

Bell. The socket of a sewer pipe, into which the spigot fits. See also trumpet. Bellarmine. A fat, salt-glazed bottle or jug, usually decorated with a bearded face stamped on the narrow neck. 

Crouch Ware. Light-coloured Staffordshire salt-glazed stoneware of the early 18th century it was made from a clay from Crich, Derbyshire, the word crouch being a corruption. 

Building bricks dost firing of pottery Engineering bricks Earthenware biscuit Salt-glazed pipes China biscuit Fireclay refractories Hard porcelain Silica refractories Basic refractories... 

Holes (in electrical conductivity). The absence of an electron from a compound or crystal structure leaves a hole. Holes move through the crystal or compound under the action of an electric field, in the opposite direction to that taken by electrons. They thus behave much like electrons, but carrying positive charge. Holey Boy. A type of perforated floor in intermittent downdraught kilns firing salt-glazed pipes. 

Littler s Blue. A royal blue first produced in about 1750 by William Littler of Longton Hall, Stoke-on-Trent, by staining white slip with cobalt oxide, applying the slip to pottery-ware, firing, and salt-glazing. 

Such kilns found particular use in the firing of refractories and salt-glazed ware. 

Tiger Skin. A decorative salt glaze (q.V.), in which crawling gives a striped or mottled appearance. 

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