Stoneware clays

Clay makes an excellent material for didjeridus. Although fired clay is rigid, and even brittle, compared to other materials like wood it is also very resonant and has some unique acoustical properties that work well-suited to didjeridu playing. I use stoneware clay that is best suited to sculpting large forms and fire it to cone 10 , about 2400 degrees Fahrenheit. This produces a vitrified, hard, dense and durable instrument with exceptional resonant qualities. 

Kaolinite (theor.) Kaolin (washed) Refractory day (fireclay) Earthenware Stoneware clay clay Brick clay... 

The main raw material are the so-called stoneware clays (Table 4) which are characterized by sintering even at 1200— 1300 °C but softening at substaintially higher temperatures. For this reason, they show a wide firing interval which allows safe firing even for large ware. 

White Stoneware clays vitrify, feldspathic glazes mature... 

In this section, clays are categorized based on how they are used in the ceramics industry. The two major types of ceramic clays are china clay and ball clay. Other materials of note include fire clays, bentonite, and talc. Less refractory materials including those classified as shales and stoneware clays are also of interest. The composition, important properties, and uses for these types of clays are discussed in this section. 

Stoneware clays can be used without beneficiation or additives to produce ware with low absorption (0-5%) at relatively low temperatures (cone 8-9) [22], Fired stoneware objects usually have a buff or gray color and are used as electrical insulators, cookware, decorative items, drain pipe, tiles, and tableware [26], Stoneware can be formed by casting, throwing, or pressing. The major difference between stoneware clays and earthenware clays is Fe203 content, with stoneware clays usually having lower Fe203 than earthenware. 

Extraction Stoneware Clays Pipe-clays Boulder Clays Bentonite Fuller s Earth... 

Stoneware Clays. These clays include various readih-fusible plastic clays that are not white-burning. Some non-refractory clays of the Coal Measures are used as stoneware clays. 

Several researches have been carried out to understand the mechanism of moisture movement in clay during drying. Newitt et al. [12] and Wakabayashi [13] investigated the moisture movanent in clay by liquid diffusion and vapor diffusion, which affect the drying characteristics particularly the falling rate. They concluded that the liquid diffusion dominates the movement until about 20%-dry basis in moisture content for stoneware clay and 30% for the mixture of 80% Kibushi clay and 20% feldspar. Wakabayashi [14] also evaluated the effective moisture diffusion coefficient of some sorts of clay such as Kibushi, Gairome, stoneware, feldspar, and their mixtures. The effective diffusion coefficient is available for the brief description of the moisture movement behavior. The effective diffusion coefficient D can be defined by... 

Stoneware clays have particular characteristics. They are in general very siliceous, almninous and contain rather significant proportions of potassimn, which acts as flux. These clays have the properly of vitrifying gradually with the rise in temperature without becoming deformed they yield an opaque material, often brown in color, variable according to the impmities contained in the initial mixture. 

A great variety of aluminium-silicate bearing rocks, plastic when wet, hard when dry. Used in pottery, stoneware, tile, bricks, cements, fillers and abrasives. Kaolin is one type of clay. Some clay deposits may include appreciable amounts of quartz. Commercial grades of clays may contain up to 20% quartz. 

A type of clay composed of mixed silicates and used for refractories, ceramics, tile and stoneware. 

---