coatings

a quiet interval of a few days’ calm after the wild weather we have been having, and a chance to glaze fire some of the  pots that have been hanging around since August. I glaze out of doors, so I prefer it not to be raining, and Friday and Saturday were sunny perfect days. on Saturday afternoon I sealed the kiln up, lit the burners at ten thirty, leaving them at a reasonable pressure, and went to bed. up at three, five thirty, six thirty and then eight thirty, I got the top temperature of 12 66 (cone eleven half over) at two in the afternoon and turned everything off. even though I close the burner ports put a couple of insulation bricks over the flue and seal the spyhole with clay, it drops the first hundred or two degrees C alarmingly quickly.

a lovely green flame for six hours; all those copper glazes.

the weather got quite cold, but still calm and clear, and none of the fog that was prophesied. this morning the sun shone through the garden, illuminating the remaining leaves.

frost on the roof took several hours to melt, at the back of my house it is shady and cold.

I opened the kiln at about nine, first glance – ooh there’s an awful lot of black, I put that glaze on a bit thick …..

by eleven thirty my spot in front of the kiln shed has enough sun at the right angle to photograph the pots. the sun on my back is quite hot. this is a refiring of one of last year’s porcelain pieces, a dip in the blue matt glaze which has cobalt and copper in it. a lot runs off again as these porcelain pots are pretty much vitrified; I use Audrey Blackman or Southern Ice porcelain. this leaves great random patterning of thinner watery glaze, and although the underlying barium carbonate glaze makes colours a little bright and crude, the fact that it is a re-fire helps to calm the colours down.

inspired by Doug Fitch’s slip decorated earthenware I got carried away with my porcelain slop and used it in various ways. I tried using a piece of clay as a stencil, then gluing it to the pot with more slop, brushing the porcelain over the added piece and the pot. I built up some quite thick applications.

on this one I put lumpy sloppy porcelain onto the pot surface with my fingers, and then scraped a simple shape through it with a wire brush.

this press-moulded dish got the same treatment, but I prefer not to put the barium glaze on something that could conceivably be used for food, however ridiculously not-a-food-surface it has, so I used the blue/grey mat glaze. which works well, it gives a very stony effect.

this pot was in a cooler spot away from flames and probably reduction. it also has a coating of porcelain, not so thick, and a thin application of the copper dolomite mat glaze, which sometimes makes this pale almost celadon green, but opaque and stony mat.

I was using clay straight out of the bag, a bit soft, and the shapes reflect this, some punched in their middles, this one with scoring lines sweeping down to a broader foot. the blue mat glaze was a little thick on this one.

a refired porcelain bowl, the flow lines of the wet glaze on vitrified surface are beautiful, I am very pleased with this one.

and lastly, my big orange vase form. this is the copper dolomite glaze again, reduced well, opposite the flame of the burner and black where the top of the pot met slightly thicker glaze at the bottom of the bin when it was dipped. I only get these oranges on a very white smooth stoneware which I layer on top of an iron bearing stoneware like St Thomas. while being worked the white clay picks up some contamination from the other clay, and I get a mixture of greens and oranges over it.

you can see the whole firing, warts and all, here