High Alumina Orange

firing to cone 10 in oxidation

slow downfire at 50 deg F an hour in the interval 1850 deg F to 1700 deg F

slow downfire at 25 deg F an hour in the interval 1700 deg F to 1650 deg F

One hour hold at 1650 deg F

more low iron glazes with ever higher alumina.

These glazes have higher alumina and lithium than lower silica:alumina ratio than prior glazes. These glazes have an almost dry surface texture.

Alumina is 1.8 for the first glaze, 1.7 for the second, the silica:alumina ratio is 2 for both glazes, iron concentration ~.03. Li2O is .6 for the first, .5 for the second.

The supposition that that higher alumina and lower silica produce brighter oranges in low concentration iron glazes still seems valid.

These are high alkaline glazes, with total CaO plus MgO ~.06 the residual impurities in the feldspars and clays.

Both of these glazes contain a in excess of 20 % Aluminum Hydroxide. I suspect that the white streaks are that aluminum hydroxide which had not been Incorporated into the glaze melt.

The pots are small conical bowls ~3 inches in diameter. We show a pair of images, outside followed by inside.

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glaze sh_2016_10_1

This glaze has Alumina 1.84, and Li2O .6.

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glaze sh_2016_10_0

this second glaze, has alumina equal to 1.7, and Li2O of .5.

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