Monday, April 26, 2010


When I first started ceramics in the late 80’s I was constantly regaled with stories of the incredible properties of various “extinct” materials. Kingman spar, colemenite, barnard, lepidolite and others. I just couldn’t relate until the demise of Albany Slip. I had early on found a variety of uses for Albany slip in my glaze palette and suddenly being without it was inconceivable. It is always really serious when it touches so close to home.

Over the years since I started, I have seen Albany slip and spodumene disappear, g-200 then there was the gerstley borate scare that sent many potters for a loop. Now the new entrant into the gone the way of the dinosaurs material is F-4 soda feldspar. Like most materials, I had become pretty dependant on it’s use in various glazes, but most specifically in my clear glaze.
My clear glaze is a very exacting and temperamental glaze and is the only glaze I currently need to measure to the exact gram. Over time, I have tried tweaking it for various reasons and ended up either clouding up the glaze, creating vast fields of micro-bubbles or just plain old crawling.

I am currently in the process of testing Minspar 200 and NC-4 as a replacement for the F-4. I am doing a series of line blends to see what happens with more and less of the new feldspars as options. Just starting this, so I will keep you informed.