|Monthly Tech-Tip |
The glaze on the right is a transparent, G2926B, on a dark burning cone 6 body (Plainsman M390). On the left is the same glaze, but with 4% red iron oxide added. The entrained microbubbles are gone and the color is deep and much richer. It is not clear how this happens, but it is some sort of "fining" and is certainly beneficial. In other circumstances, we have seen big benefits with only 2% iron added.
Suspended micro-bubbles in ceramic glazes affect their transparency and depth. Sometimes they add to to aesthetics. Often not. What causes them and what to do to remove them.
Iron Oxide Red
Red iron oxide is the most common colorant used in ceramic bodies and glazes. As a powder, it is available in red, yellow, black and other colors.