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Kingman Feldspar

Description: Potash Feldspar

Oxide Analysis Formula
CaO 0.10% 0.01
K2O 12.01% 0.73
Na2O 2.80% 0.26
Al2O3 18.72% 1.05
SiO2 66.17% 6.31
Fe2O3 0.11% -
LOI 0.08%n/a
Oxide Weight 572.75
Formula Weight 573.21

Notes

No longer available. When looking for a substitute, note how high KNaO content in this. It is much higher than Minspar or Custer. G200 HP, although having a different ratio of K2O/Na2O shares the high KNaO content (and other oxides levels are very similar).

Related Information

Which common American/Canadian feldspars can substitute for each other?

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Feldspars melting

Feldspars are employed in glaze recipes as melters. So comparing their melt fluidities should be helpful in deciding if one can substitute for another (of course, if possible a soda predominant feldspar should be substituted for another soda spar). Feldspars don't melt alone at cone 6 (2200F) so we mixed each with 15% Ferro Frit 3195. Nepheline Syenite is obviously the champion melter here. Other similar ones can be spotted easily. In the end, degree of melt is a valid consideration in determining if one feldspar is a viable substitute for another in a recipe. Even if the feldspar you want to substitute does not melt as much a little frit can be added to the recipe to make up for the difference (e.g. even just 1 or 2%).

Links

Materials Custer Feldspar
The most common potash feldspar used in ceramics in North America. While having been a standard for many decades its supply appears in doubt in 2024.
Materials G-200 Feldspar
Typecodes Feldspar
The most common source of fluxes for high and medium temperature glazes and bodies.
By Tony Hansen
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