a new firing
and so, the kiln had cooled enough to open yesterday. I was a little anxious, because the clay the cones were set in had shattered right at the beginning of the firing – I had set them too late, and in a clay with not much grog. but I keep a detailed log of every firing, so I wasn’t too worried – as long as the debris had fallen onto the kiln floor and not onto any pots.
here is my first view, as the top bricks come out … of the so called artificial nuka glaze. nuka is a Japanese glaze made of rice straw ash, very high in silica. you can make something similar with wood ash, adding feldspar and quartz or flint. it should be opaque and white … this “artificial nuka” is not, it’s more like a chun and quite transparent where it is thinner.
the kiln before unpacking – cones and clay debris on the floor, no runs of glaze, all looking good!
the bottom of the kiln is rather less hot and sometimes it’s a waste of time putting things there. the crackle slip and chun combination does pretty well down there though. the green object at the front is the beaker which was slipped with clay from the fens, a very low-firing iron rich silt, and then glazed with the unwashed wood-ash – not a successful combination, as it’s pretty under-fired and a nasty green colour!
I was quite lucky with that debris. the three big bottles (or flagons) behaved beautifully and the crackle slip and chun glaze over the wash of black iron oxide has done more or less what would be expected of it. the heavily grogged clays have no trouble with the firing temperatures, and have reduced nicely on the feet of these pieces.
lack of reduction is my main quibble with this firing, pieces that were nearer the flame don’t have enough reduction on the bare clay.
handsome. I like the way the thinner application of slip on the body of the pot has allowed a soft granular grey through,
and the peeling back with the rich dark brown underneath.
this jar is the grogged pink stoneware with the slip and chun combination, over a combed surface.
here is the unwashed ash, on a dish made with st thomas (buff and textured) and I would have liked to see the bare clay more reduced on this one, but I like the stringing/running of the ash.
washed ash, as on this jar, has lost some of its flux and really needs to be in combination with a bit of clay and feldspar to make a nice glaze.
there were two new footed plates glazed with a ladle of ash and water poured onto them and fired at the top of the kiln – again, the unwashed ash wins here, it is much nicer. and thank heavens I got some toasty reduction on the bare clay on this one. it gets a high mark from me!
here is that artificial nuka. not sure about this yet, but I think it may be consigned to being a liner glaze. I hope to find a good recipe for a nuka with wood ash, possibly Steve Parry’s recipe which is in the new edition of Phil Rogers’ book on ash glazes (which is where I found the artificial nuka). what I want are a couple of glazes which are food friendly, but work with the mark making and the ruggedness of my pots.
you can see the whole firing here
