my first glaze firing for almost four months. it is so much more pleasant in the summer. I got up before five to turn the burners up – 617 C in spite of one burner being out – the spiders again, I suppose. I relit it and it was a bit noisy but no more trouble.
the sun was a big red disc at five, just up, but the camera read the red as white, not half as pretty.
my garden blackbird was performing as usual; the mysteries of a bird’s singing voice are explained thus:
“the syrinx, a kind of double voice box at the bottom of their windpipe, is two sets of membranes and muscles where the windpipe branches into the lungs. these vibrate at high frequencies as air is exhaled. In fact, while singing, a bird can alternate exhaling between its two lungs and thereby sing in harmony with itself.”
I have watched him singing more this spring – he fluffs up his feathers and points his beak to the sky, keeping a beady eye on rivals from side to side. sometimes he utters a fluting phrase while skipping along the roof ridge, spreading his tail like a fan.
the wild garden is a joy – I walk up and down to check the kiln every half hour, taking in the cow parsley and the red campion.
the trees are beginning to grow into a real but miniature copse in the corner, and the rowan is in full flower just now.
the early morning light picks out every delicate branching flower and stem and leaf.
moon daisies, I call these, but they are really ox-eye daisies.
after forty hours the kiln is cool enough to open. you can see I stopped the firing before cone eleven had done more than wilt slightly. the lower half of the firing was occupied by a saggar made of kiln shelves. I had trouble getting reduction after a thousand degrees – it didn’t start reducing properly until over eleven hundred. normally I like to get a heavy reduction between ten thirty and eleven thirty and then burn relatively clean , although still reducing. I think my flue is the problem here, it had started to come apart, so I couldn’t close it up as much as I should have.
pots allowed to cool slowly
the saggar firing was a failure, I had filled all the gaps at the bottom and sides, and it seems to have prevented the heat getting in, so that the shavings hadn’t burnt away and the glaze on the pots is still powdery. they will all have to be re-fired I am afraid.
this one didn’t have glaze on it, so I have to decide whether to leave it as it is or to glaze it and re-fire to stoneware temperature. the carbon will be interesting under a glaze.
the pots which were in the top half are fine but I think you can see the effect of the late reduction. this shino traps carbon with a lovely lacey effect of grey in the white if it is reduced early. I have christened this rather pure and feminine looking jar Snow-white.
I have never got this copper/tin/dolomite matt and slightly crystalline glaze to change from green to pink before – it must be due to late reduction, and the porcelain layer. usually I get green with orange.
this one is more typical, and it was just in a different part of the kiln.
I have recently mixed up a new batch of the ash-clay glaze and it takes a long time to settle down and become truly thick and glutinous, giving an almost cracked-off crawled coating. here it is over the bright orange extremaduran terracotta which I brought back from Spain.
this one was on the hotter side of the kiln, and it is a different version of the copper/tin/dolomite glaze with less copper and a dose of cobalt in it. the cobalt shows more on the edges, as a greeny-blue tinge.
I refired these three porcelain bottles; they had the barium carbonate glaze on and were looking a bit boring, so they got a thin coating of the same glaze as above. the barium makes the blue much brighter. I think I will give them a coat of something else and re-fire again.
this is a new glaze, basically an iron rich temoku with its alumina content much reduced. I did not expect this metallic plum colour, but it is rather beautiful over the porcelain. it came from some experiments in Ceramic Review showing how reducing the alumina content would produce a crystalline effect, a speckled mustard coloured matt glaze – my firings are a little high for this one really. seems there was not much reduction going on here though – iron should turn green in a reduction firing.
so, some frustration and some surprises, and another firing due very soon. you can see the pots here