Glazing Gunk

Returning ceramics students might notice the new test tiles on the glazing shelf in the ceramics studio. Behind the tiles, carefully ordered commercial glaze bottles are lined up, reaching as far as the hand-labeled jars. This is one of ceramics teacher Pete Gunkleman’s ongoing projects– making and formulating glazes in the studio. Compared to other artistic projects, it may seem less lofty, but it is indeed a transformative process for both Gunkleman and the ceramics program. 

Glazes are made up of three main chemicals: silica, fluxes, and a stabilizer –usually the clay. Each provides the glassy texture, the hue, and the shape produced by the glaze application. Gunkleman described the process, saying, “There's a lot of work and testing that goes into making glazes. Lithium carbonate, copper oxide, manganese carbonate, strontium carb— all of this stuff goes into our glazes. And then I can use these components to mix them all together in a specific ratio, so that it has all the right amount of flux to make it melt at the right temperature.”

He continued with an analogy between glazes and a favorite cookie recipe: “You either think it is ideal, or you think it would be good if the cookies spread out a little bit more, or baking with no oatmeal.” 

Gunkelman also spoke to some of the difficulties he’s faced: “ I think one of the challenges is that some of the recipes that you find that you want to try, they don't make those ingredients anymore.” The studio contains multiple art books specifically about glazes, including formulas for glazes that Gunkleman attempts to replicate. He points out, “They don't make Custer Feldspar anymore. It's 62% of that glaze, and so since the recipe is gone you’ll have to find out how much of each element is in Custer Feldspar and make some sort of replacement. You'd have to reformulate it.” 

Gunkleman truly believes in the experimental and creative meaning of this project, and stated, “I spent a lot of time getting really good at the form and making beautiful shapes, and now I'm at a place where I'm thinking a little bit more about what goes on in these shapes. So I'm developing glazes that I think would work really well on the forms that I'm making, and specifically ones that work in our electric kilns.” 

By experimenting with different shapes and glazing compositions, Gunkelman strives to replace expensive commercial glazes with “homemade” glazes at a lower cost and with greater availability. He concluded, “Yeah, a lot of chemistry. And yet we're in art class.”