Bentonite is a fine powder that is a grey-tan color. As typical for ceramic use, this is a sodium bentonite and is a common additive to both glaze and clay. It's very small particle size makes this material extremely plastic. The small particle size also stays in suspension in water, lending it to function as a suspending agent in glazes. Bentonite can also be used as a glaze thickener in small amounts as an alternate to CMC Gum.
Adding bentonite to a clay body in small amounts -- about 2% -- can add strength to green and dry clay, as it binds clay together strongly. Additionally, bentonite can increase the plasticity of a clay body, but this addition can also increase the shrinkage of a clay body. Bentonite can also decrease the drying rate.
Bentonite is a fine powder that is a grey-tan color. As typical for ceramic use, this is a sodium bentonite and is a common additive to both glaze and clay. It's very small particle size makes this material extremely plastic. The small particle size also stays in suspension in water, lending it to function as a suspending agent in glazes. Bentonite can also be used as a glaze thickener in small amounts as an alternate to CMC Gum.
Adding bentonite to a clay body in small amounts -- about 2% -- can add strength to green and dry clay, as it binds clay together strongly. Additionally, bentonite can increase the plasticity of a clay body, but this addition can also increase the shrinkage of a clay body. Bentonite can also decrease the drying rate.