|Monthly Tech-Tip |
The outsides of these mugs are glazed using the G3933 recipe. Its speckle depends on the natural agglomeration that occurs in 200 mesh red iron oxide powder (the slurry was not ball millled or sieved so as not to break them up). Rutile and tin oxide are also present to help variegate the color. The body is M390, a red burning stoneware. At cone 6, using the C6DHSC schedule, the speckle is slightly more vivid in the one on the right. The drop-and-hold and slow-cool C5DHSC firing schedule used on the left helped develop the melt well even though the firing temperature is lower. The color also bleeds less across the color boundary on the lip at cone 5. The inside glazes are L3500G.
Also called "middle temperature" by potters, cone 5 (~2160F/1180C) refers to the low end of the temperature range at which most hobby and pottery stonewares and porcelains are fired.