Redart
Red Firing Earthenware
Chemistry
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Volatiles
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Links to Other Materials
- Goldart - Related
- Roseville Clay - Related
- Salt Lick - Related
- Newman Red Clay - Alternative
- Calvert Clay - Alternative
- Redearth - Alternative
- Banta Red Clay - Alternative
- Cache
Miscellaneous
- Family: Clay Other
- Region: North America
- Mined At: Unspecified
- Raw Mineral: No
- Generic: No
Notes
Redart is a red firing earthenware of moderate plasticity and low shrinkage. It fires light orange to dark red depending on firing temperature from cone 06 to 3. It achieves its best color at cone 02 and gives deep red color and stoneware properties at cone 1. It is airfloated to 200 mesh and is very clean 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 plastic modeling and throwing bodies, however some plastic additions of ball clay will be necessary. It can be used as a casting body without any additions, although it is desirable to diversify recipes to achieve better consistency and less dependence on the quality of one material alone.
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 mined from a large deposit and the company is confident in its consistency and long term availability.
Sample body recipes for low fire terra cotta:
Redart Casting mix #1062
---------------
10 Kaolin
50 Redart
25 Nepheline Syenite
15 Large Particle size kaolin
33.7 Water
0.15 Soda Ash
0.65 N Brand Sodium Silicate
For redder color you can replace the kaolin with more Redart but dry strength will be lower. You can even use straight redart for casting.
Redart very plastic throwing body #3322A
----------------
40 Redart
40 Banta Red Clay
10 Talc
10 Ball clay
This body has remarkably good plasticity yet its drying performance is also very good. It is melting by cone 4 and is quite vitreous by cone 02. Talc in low fire bodies can really improve drying while not reducing plasticity as much as other fillers, talc also increases the thermal expansion for better fit to commercial glazes.
Properties
Body Maturity - Low Fire Red Clay
Red terra cotta clays are typically 6-8 cones more vitreous than is possible with feldspar-white clay mixes. Thus where a red clay can be tolerated, materials like this can be employed to create cone 02-2 stoneware.
Data
- Drying Shrinkage: 5.5%
- Firing Shrinkage
Cone 04: 2.9
Cone 1: 7.9 - Water absorption
Cone 04: 9.0
Cone 1: 1.0 - Drying Shrinkage: 5.5%
- Firing Shrinkage
Cone 04: 2.9
Cone 1: 7.9 - Water absorption
Cone 04: 9.0
Cone 1: 1.0
Linked Articles
Understanding the Deflocculation Process in Slip Casting
Understanding the magic of deflocculation and how to measure specific gravity and viscosity, and how to interpret the results of these tests to adjust the slip, these are the key to controlling a casting process.Understanding the Terra Cotta Slip Casting Recipes In North America
This article helps you understand a good recipe for a red casting body so that you will have control and adjustability.
URLs
- Data Sheet - http://www.rescoproducts.com/pds/Ceramic%20Clays.pdf
Suppliers
- Cedar Heights
- RESCO Products
Authors
- Tony Hansen (Owner)
XML
<?xml version="1.0" encoding="UTF-8"?>
<material name="Redart" descrip="Red Firing Earthenware" generic="0" rawmineral="0" searchkey="Red Art" loi="4.80">
<families>
<family name="Clay Other"/>
</families>
<regions>
<region name="North America"/>
</regions>
<oxides>
<oxide symbol="CaO" name="Calcium Oxide, Calcia" status="" percent="0.260" tolerance=""/>
<oxide symbol="MgO" name="Magnesium Oxide, Magnesia" status="" percent="1.590" tolerance=""/>
<oxide symbol="K2O" name="Potassium Oxide" status="" percent="4.150" tolerance=""/>
<oxide symbol="Na2O" name="Sodium Oxide, Soda" status="" percent="0.380" tolerance=""/>
<oxide symbol="P2O5" name="Phosphorus Pentoxide" status="" percent="0.220" tolerance=""/>
<oxide symbol="TiO2" name="Titanium Dioxide, Titania" status="" percent="1.090" tolerance=""/>
<oxide symbol="Al2O3" name="Aluminum Oxide, Alumina" status="" percent="15.510" tolerance=""/>
<oxide symbol="SiO2" name="Silicon Dioxide, Silica" status="" percent="64.950" tolerance=""/>
<oxide symbol="Fe2O3" name="Iron Oxide, Ferric Oxide" status="" percent="7.050" tolerance=""/>
</oxides>
<volatiles>
<volatile symbol="" name="" percent="4.800" tolerance=""/>
</volatiles>
<references>
<reference name="seealso" reason=""/>
<reference name="seealso" reason=""/>
<reference name="seealso" reason=""/>
<reference name="seealso" reason=""/>
<reference name="seealso" reason=""/>
<reference name="seealso" reason=""/>
<reference name="seealso" reason=""/>
</references>
<suppliers>
<supplier name="Cedar Heights" country="00" url="" label=""/>
<supplier name="RESCO Products" country="US" url="www.rescoproducts.com" label=""/>
</suppliers>
<notes>
<note>Redart is a red firing earthenware of moderate plasticity and low shrinkage. It fires light orange to dark red depending on firing temperature from cone 06 to 3. It achieves its best color at cone 02 and gives deep red color and stoneware properties at cone 1. It is airfloated to 200 mesh and is very clean 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 plastic modeling and throwing bodies, however some plastic additions of ball clay will be necessary. It can be used as a casting body without any additions, although it is desirable to diversify recipes to achieve better consistency and less dependence on the quality of one material alone.
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 mined from a large deposit and the company is confident in its consistency and long term availability.
Sample body recipes for low fire terra cotta:
Redart Casting mix #1062
---------------
10 Kaolin
50 Redart
25 Nepheline Syenite
15 Large Particle size kaolin
33.7 Water
0.15 Soda Ash
0.65 N Brand Sodium Silicate
For redder color you can replace the kaolin with more Redart but dry strength will be lower. You can even use straight redart for casting.
Redart very plastic throwing body #3322A
----------------
40 Redart
40 Banta Red Clay
10 Talc
10 Ball clay
This body has remarkably good plasticity yet its drying performance is also very good. It is melting by cone 4 and is quite vitreous by cone 02. Talc in low fire bodies can really improve drying while not reducing plasticity as much as other fillers, talc also increases the thermal expansion for better fit to commercial glazes.</note>
</notes>
<testdata>
<testitem testname="7" value="5.5%"/>
<testitem testname="7" value="Cone 04: 2.9
Cone 1: 7.9"/>
<testitem testname="7" value="Cone 04: 9.0
Cone 1: 1.0"/>
<testitem testname="7" value="5.5%"/>
<testitem testname="7" value="Cone 04: 2.9
Cone 1: 7.9"/>
<testitem testname="7" value="Cone 04: 9.0
Cone 1: 1.0"/>
</testdata>
</material>
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