GA6-C
DraftDescription
GA6-C is a Cone 6, Alberta Slip-based cobalt-free glaze that produces a rich, variegated blue finish through rutile and iron interaction. It is most effective on dark-burning clay bodies or white bodi
Original Author
Tony Hansen
Usage Instructions
GA6-C is a Cone 6, Alberta Slip-based cobalt-free glaze that produces a rich, variegated blue finish through rutile and iron interaction. It is most effective on dark-burning clay bodies or white bodies underlaid with a dark-colored engobe. The glaze displays significant variegation, ranging from deep steel blue in thick applications to amber or brown tones where thin. Firing requires a slow-cool cycle (e.g., C6DHSC) to facilitate the development of the blue crystalline effect; failure to slow-cool typically results in an undesirable brown aesthetic. Perform routine testing when sourcing new batches of rutile, as its chemical composition can vary. If drying shrinkage or cracking occurs, adjust the ratio of roasted to raw Alberta Slip: increase roasted material to reduce shrinkage, or increase raw material to improve dry strength. Maintain a slurry specific gravity between 1.43 and 1.45 for optimal application. Excessive thickness may cause blistering and crawling; excessive thinness may result in dull, unvariegated brown surfaces. Avoid adding opacifiers like tin oxide, as they may inhibit the rutile-driven blue development.