G1216L - Transparent for Cone 6 Porcelains

Modified: 2017-07-19 22:24:03

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

Material	Amount
Minspar	8.20
Ferro Frit 3134	10.30
Ferro Frit 3124	22.70
Wollastonite	14.40
EPK	18.60
Talc	4.10
Silica	21.60
99.90

Notes

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.

Related Information

Links

Recipes	G1216M - Cone 6 Ultraclear Glaze for Porcelains Substitute for low expansion cone 6 G1215U, this sources MgO from talc instead of a frit
Recipes	G1215U - Low Expansion Glossy Clear Cone 6 A recipe sourcing high MgO (from Ferro Frit 3249) to produce a low expansion glass resistant to crazing on lower silica porcelains.
Recipes	G2916F - Cone 6 Stoneware/Whiteware transparent glaze Crystal clear industrial dinnerware glaze
Articles	G1214M Cone 5-7 20x5 glossy transparent glaze This is a base transparent glaze recipe developed for cone 6. It is known as the 20x5 or 20 by 5 recipe. It is a simple 5 material at 20% each mix and it makes a good home base from which to rationalize adjustments.
Articles	Bringing Out the Big Guns in Craze Control: MgO (G1215U) MgO is the secret weapon of craze control. If your application can tolerate it you can create a cone 6 glaze of very low thermal expansion that is very resistant to crazing.

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