Martz Memories by
In the early years following WW II, ceramics teachers frequently exchanged ideas about new materials and supplies. Several exchanged glaze formulas, and encouraged their students to do the same. A chemist, and knowledgeable about glaze chemistry, Karl Martz made sure we knew the major fluxes, refractories, colorants, matting agents, and how each might affect the glaze or ceramic piece at any stage of its birth or during its expected life. This was our responsibility.
Before we placed a piece on the “firing cart,”(the cart that held pieces ready for firing), we made a rough sketch and a carbon copy, of the pot, or sculpture. The top sketch, with its pertinent data, went with the pot as far as the kiln. The carbon copy stayed in the student’s booklet. Karl provided the booklets. Desired firing temperatures were always recorded in the booklets, for nobody wanted an earthenware pot fired to stoneware temperature.
Students experimenting with glazes, often put test cookies on the firing cart with the hope of seeing an interesting glaze result return. We would work with a glaze formula that already showed promise, and add or subtract formula ingredients. We took care to leave a note to say where in the kiln we would like the test-cookie to be placed.
Kiln firings were infrequent at the
beginning of the semester, but more frequent towards semester’s end. We found it difficult to get our pottery-
throwing and sculpture-building done and still get our glaze-test cookies into each
kiln firing. I confess to being one of
the glaze experimenters who felt rushed.
I well remember one time towards the end of a semester when I got my fired
tests out of the kiln. One cookie had a
fired glaze on it that showed much promise.
I sat at the work-table with my still warm glazed tiles in hand, and was
enjoying the results when Karl came by, and I showed him the promising
glaze. He studied it carefully. “Interesting,” he said. “What’s the formula,
“I’m nor sure, “I said, lamely.
Ashamed of my negligence, I shrank into my shell. In the many years that followed, I made hundreds of glaze tests, but never again did I make them without a written record of the formulas. I had learned my lesson.