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Ravenscrag Slip 1900F Calcined

Alternate Names: Ravenscrag Slip Calcined

Oxide Analysis Formula
BaO 0.30% 0.01
MgO 1.90% 0.16
CaO 11.10% 0.68
K2O 3.30% 0.12
Na2O 0.50% 0.03
TiO2 0.40% 0.02
SiO2 67.80% 3.89
Fe2O3 0.90% 0.02
Al2O3 13.80% 0.47
Oxide Weight 344.76
Formula Weight 344.76


The chemistry of this material is slightly different than for raw Ravenscrag Slip (it does not lose any weight on firing, so it supplies more of each of the oxides to the fired glaze, 9% more). This chemistry provided here assumes complete calcination (to at least cone 04). However there is an issue. The page at recommends roasting to only 1000F, at that temperature it looses only 3% weight on firing.

Another issue is particulates. When calcined at 1900F, particles sinter together into larger ones, requiring glaze ball milling. But at 1000F this does not occur.

Related Information


Ravenscrag web site
Ravenscrag Data Sheet at Plainsman Clays
Typecodes Clay Other
Clays that are not kaolins, ball clays or bentonites. For example, stoneware clays are mixtures of all of the above plus quartz, feldspar, mica and other minerals. There are also many clays that have high plasticity like bentonite but are much different mineralogically.
Materials Ravenscrag Slip
Materials Ravenscrag Slip 1000F Roast

By Tony Hansen

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