>I fired projects last semester with no problems. I have an electric kiln that I use Amaco Glazes. We apply 2-3 layers of glaze that come out glossy. I fire them at cone 5. The last few firings the glazes are discolored and have a matte finish. I have looked into it some - and it says that it is underfiring the projects. Does anyone have any advice of what I should change on the kiln or if I need to do something different. Any help would be appreciated.
Here are three ways to produce matte glaze surfaces.
If the glaze did not get hot enough to melt completely, it may feel a bit like fine sandpaper.
Try setting a piece so it can be seen when looking in through the peep hole. When the kiln reaches temp the glazes should all look very glossy if they are thick enough and if they are hot enough to melt.
Some glazes are formulated to form a microscopic crystalline surface during cooling, but when at peak temperature they too are glossy. For these glazes, slower cooling allows for a more matt surface than faster cooling. These feel smooth, but have a softer look than glossy or under fired glazes. They can be very nice on beautiful pottery forms and on sculpture. I have seen some exquisite vessels with matte glaze decorated by brushing or trailing a motif or design on it using another color or a clear gloss glaze.
Sometimes a thin application fails to cover all the texture of the clay, so it is more matte looking.
Marvin Bartel, Ed.D., Professor of Art Emeritus
Goshen College, 1700 South Main, Goshen IN 46526
studio phone: 574-533-0171??
"Art is me when I am myself." ... a kindergarten girl when asked, "What is art?"
"You can't never know how to do it before you never did it before." ... a kindergarten boy working with clay for the first time.