|Monthly Tech-Tip |
B-Mix is a popular high-ball clay very plastic grey cone 10R stoneware in North America. The two mugs on the left have pure Ravenscrag Slip on the inside (the middle on the outside also), it fires almost transparent with a slightly silky surface. Pure Alberta Slip is employed on the outside of the left one and the inside of the right one. The outside of the right one is RavenTalc silky matte. In all cases the Ravenscrag and Alberta Slip are mixed half-and-half calcined and raw. B-Mix fires dark enough and with enough specks that a normal transparent glaze is not very interesting. But these Ravenscrag ones look much better (for use as a liner glaze).
Both pieces have a transparent glaze, G1947U. The Fire-Red (a blend of Plainsman A1/M2 and St. Rose Red native clays) was slurried up, dewatered to plastic form and then wedged into the B-Mix (the left piece has 10%, the other 20%, the bar in front shows the pure material). The A1 supplies most of the speckle, the St. Rose and M2 impart the color. This addition does not affect the working properties of BMix (it still throws very well). An added benefit is that pieces dry harder and with less cracking. Fired strength and maturity are minimally affected (porosity stays around 1%). With a 20% addition, the surface of the unglazed clay is almost metallic. Silky matte glazes, like G2571A, are also stunning on a body like this.
GR10-C - Ravenscrag Cone 10R Silky Talc Matte
Just Ravenscrag Slip plus 10% talc produces a visually variegated surface that feels silky and looks stunning!
GR10-A - Pure Ravenscrag Slip
Ravenscrag all by itself makes a great cone 10 reduction semi-gloss glaze. It also has great working properties.
GA10-A - Alberta Slip Base Cone 10R
Alberta Slip at 60:40 calcine:raw makes a great tenmoku-like glaze at cone 10R