MnO2

Back while working at Cleveland State I tried my hand at both reduction luster and oxide saturated glazes to get metallic surfaces and ran across my notes recently and decided to resurrect at least a couple of the formulas.  The reduction luster glaze was fired in a sealed sagger using some organic materials to try to create localized reduction and as per the original notes the test came out fine. The big problem with the tests however is that after a number of times trying to photograph the test pods, the results look anything but interesting. The surfaces are a smoky silver metallic with flashes of iridescence especially where the glaze is thicker with it turning a reddish copper on the high points where it breaks though and the only way to see this is in person, on hold for the time being. I decided to move on to the MnO2 saturate glaze which was originally based on a formula with 22% red iron oxide (!) though with a number of tests I was able to take an alkaline clear glaze and add a moderate level of manganese dioxide and a few other chemicals to the recipe to get a reasonably durable bronze to smoky grey surface while using far, far less of the MnO2. The tests have reached a point where I need to move beyond pods and glaze rings and I decided to throw a teabowl that has a overall matsukawa texture to be the next step in the process. For anyone keeping track, the glaze I am currently retesting uses less than the original amount of MnO2 and is much easier to work with though I would still recommend rubber gloves (and a mask) in use at all times. I will update when I can get a few tests in an upcoming glaze fire.