Earlier this summer (2024) I decided to fire my gas kiln several times, rather than firing my old wood kiln. These would be the pots for sale at our annual Holiday Kiln Opening in November and December.
There were several reasons for this. One is that I’m getting older and filling and firing the wood kiln is a daunting task – a week of packing the kiln, a week of firing, a week to cool it down and then 1500+ pots to clean up for our sale.
Firing the gas kiln is in some ways easier, though no less demanding in other ways. It holds fewer pots, so the production cycle is different. I still made hundreds of my usual shapes, and as always, a few new ones. But they all needed to be bisque fired to 1800F to shrink the clay before being glazed and fired again.
After unloading each bisque firing I glazed and decorated them, and put them back into the gas kiln for a second, hotter glaze firing to 2300F. I did this five times between August and November, stamping all the pots “g3”, marking the third cycle of gas kiln firings I’ve had (the others during Covid).
In the process I learned more about the idiosyncrasies of my materials and the kiln. Each firing has produced very exciting and compelling results, driving me to continue to expand my gas kiln glaze repertoire.
Another reason I chose to use the gas kiln this time is out of aesthetic curiosity. I have many ceramic interests, some from my childhood, BC (before Cardew, my mentor), and others more recent. A different tool, or instrument (the gas kiln), is allowing me to explore new aesthetic terrain, pushing me to create new glazes and master exactly how to fire them to get the best results.
The theme of reconciliation also keeps popping up – between industrial and artisanal, fine art and folk art, and the ubiquitous question of art vs. craft. The boundaries of what once seemed oppositional now feel fuzzy, and that’s fine with me.
What’s in the new glazes?
The predominant ingredient in all the glazes is one of three different granites. Together they fall into the glaze category known as “celadons.”
One granite, “Salisbury Pink,” is from a quarry near Salisbury, NC. Despite its name, it fires to a lovely pale blue color which I call, “Blue Pearl.”
With the addition of just 1% iron oxide, it goes a slightly darker blue. With the addition of 2% bone ash, which contains phosphorous, it goes a streaky, milky, opaque blue. Slapping a dash of a glaze containing a small amount of copper oxide on top produces splashes of purple on some of these pots.
Another granite, called “Sloan,” from near Blacksburg SC, fires to a pale celadon green. This glaze looks good applied on top of the slip-trailed line motifs on many of the pots.
The third one is “Chandler Rock,” a felsite from Kirksey’s Crossroads near Edgefield, SC, and is similar to “Sloan.
I love the depth of their colors, particularly when the glazes are applied thickly.
These celadon glazes are echoes of their ancient Chinese, Japanese, and Southeast Asian antecedents, which have long provided inspiration to me any potters around the world.
Additional bright colors, mostly yellow, are provided by inclusion stains, adding a sparkle and gaiety to my palette. I’ve also indulged in an affair with a copper red glaze, which has its origins in luxuriant Chinese glazes from the 9th century.
The ways these glazes interact with the two liquid clays, or “slips,” which I use as an undercoat beneath the glazes, adds an additional richness and complexity. Their overall character is smooth, silky soft, and luxurious.
The crackled surfaces of these glazes, known as crazing, is caused when the glazes shrink a little bit more than the clay body during the cooling cycle of a firing, like a wool sweater which shrank too much in the drier and is too small to fit properly when you put it on. Is this a flaw? It could be seen as such as the pots are a little more porous, and not quite as strong, but it adds an interesting visual and aesthetic complexity to the surface which, as my brother James suggests, looks like, “mycelium and other components of the soil’s biosphere.” I agree! Thank you, James!
Many of the old crazed Asian celadon-glazed pots I so admire now reside proudly in museums and collections worldwide. I rest my case, although I am planning to change my clay body next time I fire my gas kiln in order to try to make the glazes fit.
I hope you enjoy these pots as much as I do!
