Redart is a red firing earthenware of moderate to low plasticity and low shrinkage. It fires light orange to dark red depending on firing temperature from cone 06 to 3. It fires much stronger and denser at cone 04 than 06 and achieves its best color/strength compromise at cone 02. It produces deep red color and stoneware properties at cone 1. It is airfloated to 200 mesh and has a long firing range. This is a very popular ingredient in clay bodies made across North America and it has been available for many years.
This material is quite high in iron thus the powder is a deep red color and quite messy to work with. Redart is also used by potters in glaze recipes, sometimes up to 60%.
Redart can be used as a primary component in brown and red burning modeling and throwing bodies (however significant plastic additions of ball clay (e.g. 20%) will be necessary to get sufficient plasticity). For plastic terra cotta bodies the highest proportion of Redart possible is desirable to achieve the needed color. For a body containing 75% Redart and no other plastics, at least 5% bentonite is needed to get enough plasticity for throwing.
Redart can be used to make casting bodies without any other additions. It will produce very good red color and will deflocculate and cast well. It is possible that a small addition of plastic clay might be needed to give it better strength to pull away from the mold. Also, additions of silica (for glaze fit) and a frit (for maturity) are also options.
While Redart can be used as a source of iron in high temperature bodies, it will produce brown rather than red coloration. This is because the fluxes are intimately mixed with the iron and fuse it to a darker color. To get red in oxidation or reduction at higher temperatures you must use refractory clays with iron or iron bearing fireclays. However there is good reason not to use low fire reds as fluxes in high fire bodies: The fluxes in the red clays don't dissolve cristobalite like feldspar does, the result can be thermal expansion related ware failure.
This material is quite high in iron thus the powder is a deep red color and quite messy to work with. Redart is also used by potters in glaze recipes, sometimes up to 60%.
Redart can be used as a primary component in brown and red burning modeling and throwing bodies (however significant plastic additions of ball clay (e.g. 20%) will be necessary to get sufficient plasticity). For plastic terra cotta bodies the highest proportion of Redart possible is desirable to achieve the needed color. For a body containing 75% Redart and no other plastics, at least 5% bentonite is needed to get enough plasticity for throwing.
Redart can be used to make casting bodies without any other additions. It will produce very good red color and will deflocculate and cast well. It is possible that a small addition of plastic clay might be needed to give it better strength to pull away from the mold. Also, additions of silica (for glaze fit) and a frit (for maturity) are also options.
While Redart can be used as a source of iron in high temperature bodies, it will produce brown rather than red coloration. This is because the fluxes are intimately mixed with the iron and fuse it to a darker color. To get red in oxidation or reduction at higher temperatures you must use refractory clays with iron or iron bearing fireclays. However there is good reason not to use low fire reds as fluxes in high fire bodies: The fluxes in the red clays don't dissolve cristobalite like feldspar does, the result can be thermal expansion related ware failure.