Ravenscrag Slip
Silty fusible low iron clay
Chemistry
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Volatiles
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Links to Other Materials
- Alberta Slip - Unspecified
- Cache
Miscellaneous
- Family: Clay Other
- Region: North America
- Mined At: Unspecified
- Raw Mineral: No
- Generic: No
Notes
This material is not typical of any other glaze material currently out there so this is likely part of the reason. Its claim-to-fame is mainly two fold:
-It is possible to use it 100% to create a silky to glossy glaze at cone 10 because it contains all the feldspar, silica and clay needed and these are supplied in majority from the natural clay.
-It imparts beautiful working properties to the glaze slurry: it suspends it and improves evenness of application, drying speed, reduces shrinkage and enables multi-layering (many of the most beautiful art glaze effects can be achieved by layering one glaze over another).
You can visit www.ravenscrag.com to learn more. The site shows a lot of very interesting glaze formulation work and recipes and comments are recorded on the site. In addition to some of the nice multi-layer effects, you will find one glaze in particular, a blue cone 6, to be quite stunning (it is a worthy successor to floating blue because it lacks its persnickety nature). If you want to dabble in developing your own glazes, Ravenscrag Slip is a great place to start.
One exciting thing that has emerged is that Ravenscrag is at home in high, medium and low fire glazes. At high temperature it can be used as-is with additions of color, opacifier, etc to create glossy and matte glazes. At middle temperature, 20-30% frit seems to work well. At low temperature 50-60% is needed. Frit 3195 at low fire produces a very attractive silky matte surface having a nature that is much more lively than the typical toilet-bowl type low fire glaze we are used to. Ravenscrag also has potential as a tile glaze since it applies well on dry ware.
Plainsman Clays made a change in the Ravenscrag recipe starting with mix number 4288 from May 2002. It now has 10% added calcium carbonate to make it melt better. If you have a material with a code number whose first four digits are lower than this, add 10% whiting to get the same results as on the web site.
You can order a sample of this material at https://digitalfire.com/plainsman/store/store.php
Linked Articles
Creating a Non-Glaze Ceramic Slip or Engobe
It is difficult to find a slip that is drying and fired compatible with your body. It is better to understand, formulate and tune your a slip to your own body, glaze and process.
URLs
- Data sheet - http://digitalfire.com/plainsman/data/raven.htm
- Data Sheet - http://digitalfire.com/plainsman/data/raven.htm
Suppliers
- Plainsman Clays
Authors
- Tony Hansen (Owner)
Pictures
-
A buff stoneware vase with 100%
Ravenscrag Slip glaze on Laguna B-Mix clay
XML
<?xml version="1.0" encoding="UTF-8"?>
<material name="Ravenscrag Slip" descrip="Silty fusible low iron clay" generic="0" rawmineral="0" searchkey="" loi="4.80">
<families>
<family name="Clay Other"/>
</families>
<regions>
<region name="North America"/>
</regions>
<oxides>
<oxide symbol="CaO" name="Calcium Oxide, Calcia" status="U" percent="4.970" tolerance=""/>
<oxide symbol="MgO" name="Magnesium Oxide, Magnesia" status="U" percent="1.890" tolerance=""/>
<oxide symbol="K2O" name="Potassium Oxide" status="U" percent="3.370" tolerance=""/>
<oxide symbol="Na2O" name="Sodium Oxide, Soda" status="U" percent="0.500" tolerance=""/>
<oxide symbol="TiO2" name="Titanium Dioxide, Titania" status="" percent="0.430" tolerance=""/>
<oxide symbol="Al2O3" name="Aluminum Oxide, Alumina" status="" percent="14.140" tolerance=""/>
<oxide symbol="SiO2" name="Silicon Dioxide, Silica" status="" percent="69.000" tolerance=""/>
<oxide symbol="Fe2O3" name="Iron Oxide, Ferric Oxide" status="" percent="0.860" tolerance=""/>
</oxides>
<volatiles>
<volatile symbol="" name="" percent="4.800" tolerance=""/>
</volatiles>
<references>
<reference name="seealso" reason=""/>
</references>
<suppliers>
<supplier name="Plainsman Clays" country="CA" url="http://www.plainsmanclays.com" label=""/>
</suppliers>
<notes>
<note>This material is not typical of any other glaze material currently out there so this is likely part of the reason. Its claim-to-fame is mainly two fold:
-It is possible to use it 100% to create a silky to glossy glaze at cone 10 because it contains all the feldspar, silica and clay needed and these are supplied in majority from the natural clay.
-It imparts beautiful working properties to the glaze slurry: it suspends it and improves evenness of application, drying speed, reduces shrinkage and enables multi-layering (many of the most beautiful art glaze effects can be achieved by layering one glaze over another).
You can visit www.ravenscrag.com to learn more. The site shows a lot of very interesting glaze formulation work and recipes and comments are recorded on the site. In addition to some of the nice multi-layer effects, you will find one glaze in particular, a blue cone 6, to be quite stunning (it is a worthy successor to floating blue because it lacks its persnickety nature). If you want to dabble in developing your own glazes, Ravenscrag Slip is a great place to start.
One exciting thing that has emerged is that Ravenscrag is at home in high, medium and low fire glazes. At high temperature it can be used as-is with additions of color, opacifier, etc to create glossy and matte glazes. At middle temperature, 20-30% frit seems to work well. At low temperature 50-60% is needed. Frit 3195 at low fire produces a very attractive silky matte surface having a nature that is much more lively than the typical toilet-bowl type low fire glaze we are used to. Ravenscrag also has potential as a tile glaze since it applies well on dry ware.
Plainsman Clays made a change in the Ravenscrag recipe starting with mix number 4288 from May 2002. It now has 10% added calcium carbonate to make it melt better. If you have a material with a code number whose first four digits are lower than this, add 10% whiting to get the same results as on the web site.
You can order a sample of this material at https://digitalfire.com/plainsman/store/store.php</note>
</notes>
<pictures>
<picture description="A buff stoneware vase with 100%<br>Ravenscrag Slip glaze on Laguna B-Mix clay" filename="ravenslipvase10r.jpg"/>
</pictures>
</material>
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