Before I went to university for my undergrad degree, I was firing earthenware to cone 04. When I was in school taking clay and glaze calculation classes (with the very amazing and talented Margaret Bohls), I was researching cone 6 on a mid-range white body. Ultimately, I missed earthenware and returned to a lower temperature. I tested many of the cone 6 glazes I had to see if they would work at cone 1. I ended up settling at cone 01 for glaze firings; results being fairly similar.
Three examples of Pam with a copper wash. The glaze is brushed on greenware, fired to cone 08 or 04. It is dry and pocky (from the lithium). I put a Black Copper and Gerstley Borate wash over it. The wash fluxes out the glaze (all the boron in the Gerstley Borate) and the copper gets-- gunmetal black to variegated turquoise. Images from left to right: thinner application of Pam and thicker copper wash (this makes the thin go brown and the thicker get rivulets of turquoise and gunmetal), thicker application - 2 coats - of Pam with the wash, last image is a test tile that has half black copper wash, half red copper wash (virtually no difference).
Blue Pam (base + .4% cobalt)
I was looking for blue. I got this one on the first try (when does that happen??). I know that cobalt can raise the melting temperature, so I am surprised this still runs at cone 01! It has great variation - from waxy to semi-gloss to spotted lithium crystals where thick, if it is thin, it will be matt and dry.
Does anyone know who Pam is?
Lower-Mid Range Tests