Glazing Mugs, Plates, and Lemon Squeezers

My kid's reaction to a calendar snafu on the first day of online school

I was able to bisque and glaze almost a full kiln last week. Studio work this summer been slow, but work has gotten done. I used up all my porcelain clay and ordered more about a month ago. I ordered it from Tacoma and they sent it USPS to a different address in Yakima. Strangely they sent the other stuff I ordered to my house. Then they had to send they back to Tacoma before sending it back to Yakima for me. 50lbs of the clay made it to my house a week or two ago. The other 50lbs appear to be trapped in the USPS black hole. The clay has left Tacoma, but the tracking doesn't identify any more movement. I assume no one at USPS wants to pick up this 50lb box during the chaos and I don't blame them. 

bisque ware waiting to be glazed, mugs, plates, citrus squeezers and bulbs

Because I used different temperature clay for different projects, I wasn't able to fire the bulbs in the same firing as the plates, mugs, and citrus squeezers, so those haven't gotten done. I keep thinking I will make time to throw some more so I can fill a kiln to fire the mugs and bulbs I finished after this last firing, but I haven't done it yet. Instead I'm working on online classes, doing union stuff, and procrastinating. Today, I am also trying to calm down my kid, whose reaction to online school has been stomping, crying, and generally freaking out. First there was an error in the timing of the first class, then the link to the second class doesn't work. After solving the first issue, she allowed up to 12 minutes for her teacher to help on the second, but just in case he didn't reply, she started freaking out immediately. Um, so my hope for the school year is that this 7th grader learns patience?

porcelain plates from the second firing, and one stoneware clay on the top right

I'm pretty happy with the plates from this batch. In the first round my glaze application was irregular on some, and because I was worried about glazes dripping in the kiln, I put the plates on stilts. This was a dumb solution, because not only did I not put enough glaze on to drip, making the plates look a little splotchy, firing on stilts also warped the plates. This time around I used more glaze and did not stilt the plates, so there's less splotchiness and all the plates are flat and even.

porcelain plates in yellow, pink and peach

I also changed the shape for most of these plates because they were done on request. The person who ordered them wanted small plates with a flat flared rim. She liked them, so three of the six porcelain plates have been sold since I took these pictures. Four of the plates were done in a groggy sculpture clay, which is serviceable, but mutes the glaze colors and doesn't look as nice.

On all the plates I drizzled other colors inside. The reds and a sparkly glaze look particularly nice in person, but the photos didn't capture the colors as well.

I also glazed three screaming face mugs I made with the porcelain clay. I used dark glazes to highlight the features and wrinkles, and a semi-transparent glaze for the entire exterior. I am not excited about the result. The faces look too white and too plain. Part of the problem is the limited number of glazes I had (partly because I used some up on the plates) and part of the problem is that I didn't leave enough of the dark glazes in the wrinkles and indents. I have ordered some new glazes so on the next batch I can bring more color, assuming the glazes also don't end up in USPS limbo.

My kid's reaction to an error in a Google Meet link on the first day of school

I think these faces would look better if I layered more colors. I usually do this with my underglazed sculpture, putting down a base coat on bisque ware before a second firing, then layering a wash of contrasting color over the first. I haven't tried that with these glazes, but I'm considering it. Underglazes and glazes handle differently, but it's worth a shot.

screaming face mug with minimal color in the eyes and eyebrows

I did minimal mixing of colors in these mugs, but I was tentative compared to my "usual" work. I also did some mixing/layering in the new lemon squeezers, but for some reason the yellow and blue showed up best and overwhelm the other colors (or maybe I forgot to use much other than blue and yellow). I know I used the red/pink on at least two pieces and now it is barely evident.

 

most of the citrus squeezers from the second batch, in both porcelain and sculpture clay

Something else happened in the glaze firing for these citrus squeezers. And this requires a bit of back-story. When I was in college, my clay professor told us that anytime we had a contained air pocket, it needed to be pierced so that the air could escape. If not, it would risk blowing up in the kiln. This is pretty conventional wisdom in the clay world and I know I've repeated it often enough. I remember one instance when I remembered too late that I had forgotten to pierce an air hole in a piece. When I opened the kiln I was surprised to see the piece had not exploded. At the time, my professor and I guessed that it was because I was using a raku clay, which is more porous than other clays.

more blue and yellow squeezers

Many years later, I joined a clay community on Facebook. One of the regular topics that comes up over and over again is that air pockets don't cause explosions during firing, only wet clay does. The reasoning goes that air is so small that it either doesn't need to escape or escapes through the walls of the clay. I allowed students to test this theory in class. Usually the pieces didn't explode, but sometimes they did. When asked, the folks in this online clay community assumed that these students must have soaked the pieces before glazing, or the pieces were simply too thick, or there was unaccounted for moisture left even after a long candle (candle means preheating the kiln to drive out excess moisture) or long drying time.

the bottoms of these two squeezers expanded due to expanding air inside during firing

It's difficult to rule out all these options with student work, but the results seemed inconclusive. This still bugs me, so I periodically test the theory. In my first citrus squeezers, I pierced the forms, leaving an unnecessary/essential escape for any heated air. This time around I did not pierce the forms. None of the pieces exploded in either firing, but in the glaze firing the bottoms of two of the pieces, which I had set on stilts in the kiln, expanded during the firing, going from a slightly concave base to a slightly convex base. Meaning that an air pocket inside did, in fact, expand during the firing and was unable to escape, suggesting that my online clay community, despite regular repetitions, is incorrect on this topic.