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Panama Cone 6 Transparent Glaze

Code: G3806C
Modification Date: 2017-10-23 15:34:42

High fluid melt glaze for reactive effects and super gloss colors

Strontium Carbonate4.44.4%
Ferro Frit 311031.131.1%
Ferro Frit 31346.66.6%
Zinc Oxide3.33.3%


This recipe was the product of a series of tests to determine the best direction for a brilliant fluid-melt transparent base glaze for copper blues and greens. Once I selected a specific recipe (Panama Blue), I removed the colorants and made adjustments to improve its slurry properties and lower the thermal expansion to stop crazing. This type of base glaze is needed because more stable transparents lose their gloss on brown bodies and when certain colorants are added. Fluid melt base glazes also produce much more interesting visual effects. But of course, they have a down sides: they can run off the ware onto the shelf if too thick! And they have an inherently higher thermal expansion so crazing is more of an issue (but it is not impossible to solve as you will see here).

This recipe is just the base, it does not have the copper and tin to make the green color. We recommend using Copper Oxide, between 1 and 1.5% (depending on the intensity of color desired).

While the previous version, B, did not craze in my tests, its calculated thermal expansion was high enough to be a cause for concern. This adjustment lowers the expansion further while keeping the same brilliant visual appearance. Two materials have also been eliminated from the recipe (their oxides supplied by the others). The chemistry of this one has reduced high-expansion KNaO and increased low-expansion MgO. This makes it melt a little less, but visually it is the same. The higher ZnO seems to help melt the extra SiO2 I also added. As a result the calculated thermal expansion has gone from 7.7 down to 7.3.

If this crazes on your clay body then consider trying a body that has a higher percentage of silica (25% would be good). It is likely possible to adjust the recipe of this glaze to hang on to the fluidity while having a lower thermal expansion, but I have not done that. It crazes on Plainsman P300, M370 but appears to be OK on Polar Ice.

Out Bound Links

In Bound Links

XML to Paste Into Insight

<?xml version="1.0"?>
<recipes version="1.0" encoding="UTF-8">
<recipe name="Cone 6 Clear Fluid-Melt Clear Base Glaze" keywords="A base fluid-melt glaze recipe developed by Tony Hansen. With colorant additions it forms reactive melts that variegate and run. It is more resistant to crazing than others." id="125" date="2016-11-12" codenum="G3806C">
<recipeline material="Silica" amount="26.300" added="0"/>
<recipeline material="Kaolin" amount="19.700" added="0"/>
<recipeline material="Dolomite" amount="8.700" added="0"/>
<recipeline material="Strontium Carbonate" amount="4.400" added="0"/>
<recipeline material="Ferro Frit 3110" amount="31.100" added="0"/>
<recipeline material="Ferro Frit 3134" amount="6.600" added="0"/>
<recipeline material="Zinc Oxide" amount="3.300" added="0"/>
<url url="" descrip="Recipe page at"/>

By Tony Hansen

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