Glaze test tiles: six stoneware glazes over two clays

January 27, 2026 · 2 min read

I made twelve test tiles, each 5 by 8 cm with a hole for hanging, six from the buff stoneware and six from the dark iron-rich body, and dipped each in one of the studio’s six house glazes for a count of three. They went in the electric kiln with the class work and fired to cone 6, roughly 1220 °C, with a slow cool because the kiln was full. Here is what came out, by glaze.

Clear: glossy and genuinely clear on buff; on the dark body it went a deep warm brown where it pooled and almost black on the flat, with tiny iron speckles bleeding through. Beautiful and not at all clear.
Celadon: pale jade green and glassy on buff, breaking slightly darker in the texture lines I had scratched in. On the dark body it went a muddy gray-green and lost most of its depth. Celadon wants a light clay under it.
Tenmoku: deep brown-black, with a rust break at the tile edges on both bodies. The dark body made the break more pronounced. This one does not care what you put it on.
White satin: soft and matte on buff, with a slight blue cast where thick. On the dark body the iron came through as a scatter of brown freckles, which I liked more than the plain version.
Shino: the surprise. On buff it was a creamy white with orange flashing at the edges. On the dark body it was almost entirely orange, with carbon trapping in gray patches where the glaze was thickest. Same glaze, different pot.
Blue ash: runny, mottled, with the blue pooling in the scratched lines and running toward the bottom edge on both tiles. Needs a thinner dip and a wider foot.

Two general lessons. First, the clay body is half the glaze; the same bucket gave twelve different results. Second, a three-second dip is thick for the runny glazes and thin for the stiff ones, so the next round of tiles will have a one-second and a five-second strip on each to see the range.

The tiles now hang on a string by the glaze buckets, which the studio has encouraged, and I have started a notebook page per glaze. The shino on dark stoneware is going on the next mug, whether or not it suits a mug.