Transparent for Cone 6 Porcelains

Code: G1216L
Modification Date: 2017-07-19 22:24:03

Incorporates some MgO (at the expense of CaO, KNaO) to reduce the thermal expansion of G1214M 5x20 glaze.

Ferro Frit 313410.3
Ferro Frit 312422.7


This glaze adjusts G1214M 5x20 to reduce its thermal expansion (incorporating MgO). It goes in the same direction as G1215U but does not add as much MgO and sources it from Talc instead of Ferro Frit 3249. The MgO is added at the expense of CaO, KNaO. Boron has also been increased a little. The thermal expansion has gone from 7.0 to 6.5. The two frits here are tuned to supply enough Al2O3 to keep the kaolin low enough to prevent shrinkage cracks on drying.

This glaze survives and 300F oven:ice-water crazing test on Plainsman M370.

It works well as a white (with 10% zirconium silicate) and as a black (5% Mason 6666 black stain).
However some users find that this do fire as glassy as our standard G2926B recipe.

Out Bound Links

XML to Paste Into Insight

<?xml version="1.0"?>
<recipes version="1.0" encoding="UTF-8">
<recipe name="Transparent for Cone 6 Porcelains" keywords="Incorporates some MgO (at the expense of CaO, KNaO) to reduce the thermal expansion of G1214M 5x20 glaze." id="117" date="2017-07-19" codenum="G1216L">
<recipeline material="Minspar" amount="8.200" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Ferro Frit 3134" amount="10.300" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Ferro Frit 3124" amount="22.700" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Wollastonite" amount="14.400" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="EPK" amount="18.600" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Talc" amount="4.100" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Silica" amount="21.600" unitabbr="kg" conversion="1.0000" added="0"/>
<url url="" descrip="Recipe page at"/>

By Tony Hansen

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