|Monthly Tech-Tip |
Alternate Names: PF-01 Potassium Feldspar, PF-01 Potash Feldspar, Mahavir Feldspar
This feldspar is being imported by Laguna Clay into North America (from India). It will be marketed as the successor to G-200 feldspar and its temporary substitute, the MFEL S3470 blend (Minspar/G-200HP blend). The chemistry of this is very similar to G-200 (this has a little more K2O, a little less Al2O3 and a little more SiO2).
The manufacturers data sheet describes it as a selected white firing high grade potassium feldspar typically used in frits, ceramic glazes, sanitary ware, table ware, white glass, TV tubes etc. The data sheet calls it PF-01 Potassium Feldspar so there is some confusion about what it will be called.
The analysis supplied here has been rationalized from that supplied on the manfacturers data sheet. It specifies plus or minus values for oxides as follows:
SiO2 +/- 1%
Al2O3 +/- 0.5%
K2O +/- 1%
Na2O +/- 0.5%
CaO < 0.3%
Fe2O3 +/- 0.02%
MgO < 0.3%
TiO2 < 0.01%
LOI 1% max
Mineralogy: 65-75% Microcline
Melting temperature: 1220C (soaking time 30 minutes)
Particle size: 2% +63 microns (the data sheet lists others but this is the one being imported by Laguna Clay)
A nylon fabric bag with no safety markings.
Lagunaclay.com will be importing this material from India. It will be called Mahavir Potash Feldspar. You can find it in the reference materials in your Insight-live.com account. You might like to leave recipes as is (naming G-200 as the material) but insert "Mahavir Potash Feldspar" as the lookup so the chemistry will be correct.
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%).
G-200 EU Feldspar
G200 Old Blend Feldspar
Mahavir PF01 Feldspar Data Sheet
The most common source of fluxes for high and medium temperature glazes and bodies.
|By Tony Hansen|
Follow me on