the glaze tests were not useless, but where I had put them on the dark stoneware and they were closer to the flame and therefore cone 11, they were not much good. of the porcelain tiles I have five I like.

from this photo of the kiln you can see cones on the left where the 11 has just started to bend a little, and on the right behind a test, cone 11 is right over. on the left is more or less the same as the kiln floor and the cones at the front which I used to determine the state of the firing. this is interesting as it means the temperature in my firing was reasonably even.

its always hard to work out exactly what made tests do what unless you make series of tests to form a grid with gradual changes of recipe. the bottom row had magnesium carbonate as well as dolomite, both of which are melters. but the two horrid shiny ones had less of the magnesium and more of the dolomite … whereas more of the magnesium gave a more grainy surface and in combination with tin oxide, the rather purple/lavender shades of the bottom left two tests. I am interested in cutting out the tin oxide, as it is very expensive. the bottom right test had no whiting (another melter) and no tin oxide, but 5% titanium dioxide to replace the opacifying effect of the tin. it is quite a pleasant glaze; the tiny amount of cobalt has combined with the copper to give that robin’s egg blue. on the whole, the bottom row are not useful. of the top row, all but the pinkish one are useful. this had more dolomite and less feldpar, no whiting, no tin and no titanium. the black test is the nearest to what I wanted, the high copper content and highest of the cobalt in the tests, with no tin, but 5% titanium dioxide (used as pure white in paints). of the blues, the right hand one has bleeding to orange at the edges, like the original glaze, so that probably makes it the most interesting. it has no tin and no titanium. a nice economical glaze! I should continue to work on these blues and black and see what more I can get. and try these on different clays and in different places in the kiln.

the rest of the firing was reasonably successful. this large pot cracked open more during the firing, so I hope it will stay in one piece now. it has a layer of white S&T material clay over the crank, which has made it slightly problematic. its the first time I have had a problem with this combination

I am very pleased with this one, it has the combing into the top layer, same combination as the pot above, it just 3 cm taller, the biggest I can get into the kiln, and it has picked up the green from the copper, so it is white with a tinge of icy green, breaking to yellow ochre.

this little pot was a success also. the link is here for the rest of the firing