alkaline glazes: a failed first glaze

When I finally started working with Greg on making pottery, we decided that we should mix up our own glazes. The commercial offerings we'd seen weren't all terribly impressive.

We wanted a variety of colors, but the glaze we most wanted to make was an alkaline glaze -- something that would connect our pottery to the folk tradition that began in South Carolina.

We had some successes later on. . .




. . . but I want to talk about the failures first. They're much more interesting.

We misremembered the first recipe we got -- what we heard was a 3:1 ratio of clay body to lime. Nothing else. For our cone 6 firing.

We didn't know that was a problem at the time.

We did some things right. We weighed everything out very carefully and wrote down exactly what we'd done. We were keen to try the glaze, so we didn't try it out on test tiles. We hadn't even made any test tiles yet. . . .

So the glaze went onto two or three mugs and went into the kiln. We waited out the firing, and anxiously opened it when things had cooled down a bit.

The mugs that had been glazed in our first alkaline glaze looked like sandpaper. They felt like sandpaper. They _behaved_ like sandpaper: the grit would come off, but only if we rubbed vigorously, and it abraded whatever we used to rub the mugs.

We tended to underfire the old kiln just a bit, so we refired the mugs when we got the new kiln. The glaze improved, but the mugs are still unusable -- there are spots that look great, and there are spots that look rough. Like sandpaper.

I'll see if I can get a picture of the mugs to post here. They're still in the barn, as a warning (and because they look pretty cool, as long as they're on a shelf ten feet up).