Cone 10 Reduction Liner and Base Glazes
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High temperatures provide the ultimate strength and durability. More correctly, they provide the OPPORTUNTIY for unmatched strength and durability. But these and other opportunities can easily be squandered if glazes are poorly formulated (causing crazing, cutlery marking, staining, devitrification, blisters, bubbles, pinholes, crawling, settling). Excessive feldspar and too little or too much clay are often the problems. At cone 10, temperature is on your side, the kiln will melt glazes having lower flux and more silica and alumina. This is ideal because SiO2 and Al2O3 are the exact oxides we want. They harden the glass, stabilize it against running, make it leach resistant. And they are sourced by kaolins and ball clays, the exact materials that impart good slurry, application and drying properties.
G1947U Transparent Glossy Base
A base transparent glossy is very important in the production of functional ware. It should have good application properties, fit the clays you use (not craze) and produce a durable clear glassy clear finish (many transparent glazes in use are saturated in feldspar, they often melt and run excessively, craze and produce non-durable surfaces). To a good transparent you can add increasing amounts of iron oxide to produce celadons, brilliant browns, tenmokus and iron crystallines. This recipe was adapted from the porcelain insulator industry. To see the recipe for G1947U click here.
Back left to right: H550, H550, H450, H443. Front: H550/555, H555, P700. All have G1947U inside, pure Alberta Slip outside.
Cone 10R porcelain with 1947U transparent (left) vs. cone 6 oxidation porcelain (right)
G2571A Dolomite Silky Matte Base
Many people love cone 10R firings because of the beauty of dolomite matte glazes on speckled clay bodies. These glazes have a pleasant silky feel unmatched by any other type at any other temperature. However many dolomite mattes have no documentation, they craze, stain and they have poor slurry and application properties. This one is different. To see the recipe for G2571A click here.
G2571A on Plainsman H443
G2571A as a liner and as a base for bamboo and powder blue. H550, H550, H443.
Ravenscrag Slip Based Glazes
Many are available on the cone 10 glazes page at ravenscrag.com.
Alberta Slip Based Glazes
Many are available on the cone 10 glazes page at albertaslip.com.
Outside: 50:50 mix of Ravenscrag Slip with Alberta Slip (plus 5% calcium carbonate). Inside: 1947U transparent. H450.