Jane Wheeler's Blog - Just another WordPress weblog

more attempts with slip

Posted jane -->on 21st May 2012

the latest firing; a qualified success. I think I reduced more than usual … I was worried that the kiln wasn’t reducing enough, with the opposite result. it took an hour or so longer, which is an indication in itself …. but there were quite a lot of pieces so slow was good in that it gave the heat a chance to settle right into the corners. the cone you can see still standing is 11, which is how I normally fire – until 11 just starts to bend. I had more success with the black clay this time, with the tall piece on the left; I glazed it inside and out with my barium matt. the inside is a good sooty black.  the green/orange black dolomite glaze has a little trick of being definitely matt almost metallic black over the super-white stoneware layering, if I place it low down at the front of the kiln, so I can more or less rely on that. I tried the large bottle behind it with a combination of my barium matt and the crawling shino. very disappointing, quite nasty in fact. I have a photo of a bowl I glazed with a combination of shino and the barium matt two years ago, but on a darker clay, and possibly the other older shino, so that’s what made me try it this time, as it was lovely!

these two pieces are good examples of what you can and can’t do with the crackle slip. I had read that it stops crackling after the first day and you need to use it fresh. this is not true. the one on the left I slipped when it was bisque fired, and left it for a couple of weeks before glazing. you could see the crazing straight away, but I was worried that the slip would fall off when I glazed. it didn’t, and it’s fine. the one on the right, the blue, has handed off some of its copper content onto the one on the left, leaving it pinkish. I was trying for this effect. but the blue one was a last minute effort – I slipped it, then glazed it before the slip was dry. result – the glaze and slip have melded and pop off the surface with a small amount of pressure.

this little beaker was slipped when green (unfired). this does make the slip a bit liable to fall off , mostly on edges, but it depends on the clay body how much crackle you get. it’s quite restrained on this, which is St Thomas white, with the new barium matt glaze I found in Emanuel Cooper’s book (9% barium). this glaze leaves a rusty tideline on the paler clays.

the back half of the kiln was pretty crowded with lots of little pots. at the top some boring – I won’t put the Cooper matt on pale clay again, but the copper dolomite worked well over it – and the same matt rather boring over the porcelain slip – which is just porcelain bits melted down and brushed on – the chun over the porcelain slip is nice though – this little beaker is rather soft and delicate. sadly it leaks, or it would be possible to use it as a coffee cup!

probably in truth the chun is too delicate for domestic use though, I think it might scratch easily.

this beaker was also on the top shelf, it is the terracotta crank body which fires very dark, the crackle slip put on before bisque firing, and the chun over the top. the slip has rather parted company with the body, but the chun has fixed it, and melted into a thicker line along its bottom edge, with the pale blue bubbling which makes it so pretty. quite a drama for such a small pot.

here the slip was put on after bisque firing, over a toasty body which had been incised and painted with I think black iron oxide. the glaze is the chun again.

this dish was slipped on the inside when green … almost a disaster, it cracked the vessel … but hasn’t the blue dolomite worked nicely over the two different coloured surfaces and the spaghetti spoon indentations! the clay body is a mix of grey stonewares, reconstituted – a bit darker than the St Thomas white, with a lot of grog in it.

this is a bit special, it is one of the pieces I painted with slip made from Dameon Lynn’s fen riverine clay, with the chun glaze as a liner, and Cooper’s barium matt on the outside. the iron and the salts in the slip have reacted with the glaze, there are some bubbly tidemarks, and it is almost shiny. I should really redo the glaze with a more matt combination to counter this shininess, but the good thing is that the barium allows the warmer colour, whereas the chun is quite grey.

this time the black dolomite glaze on the porcelain is even better – somehow the heat work has been stronger and the glaze has almost begun to flow off the pot, leaving this gingery mustardy colour in a crystallised freckle. I am so glad I have this combination to take up what otherwise tends to be a dead space in the kiln, where nothing exciting happens.

and another bit of drama – crackle slip and Cooper’s barium matt glaze on the black clay. this clay looks good with the chun, fired on the top shelf – it has almost made a tenmoku.

until the weather gets better I can’t photograph these pieces properly, but you can see the rough cut here

altogether there were eleven rejects, including that big bottle – about a quarter of the firing.

ne’er cast the clout ……

Posted jane -->on 1st May 2012

ere May is out, says the old English proverb and goodness, this year it feels like there won’t be much opportunity to cast any clouts (clothes). I am having to keep the woodstove on in the workshop, except yesterday, which was a rare sunny and warm day.

since  that Aprille with his shoures soote/The droghte of Marche hath perced to the roote, we have no shortage of water here, in over-flowing water butts and in the ground, although hosepipe bans are still in place, and the ponds still look a little low.

plant life seems to be happy with the rain, although the storm on Sunday knocked buds and new leaves off. migratory birds are back, but the weather subdues them … I hear blackcaps and garden warblers in all the woods (today a black cap perched and performed right in front of me in the green lane) and in the gardens around my house, yesterday I heard whitethroats in the hedges, and last week there was a willow warbler singing in the fringes of Bale wood … I hope he stays. the chiffchaffs have been present since the end of March.

yesterday we made the annual pilgrimage to Bullfer grove to photograph the bluebells

they grow all over the banks of the bridlepath and the hedgerows surrounding the wood, so I assume it is a place where there has been an ancient continuity of woodland. there are wild garlic clumps amongst the oaks at the northern end, but it is the beech trees that encourage bluebells, as they generally keep the woodland floor clear of undergrowth.

a lovely purple-blue mist which photographs rarely do justice to – and a sweet scent, despite the rapeseed fields quite close with their sickly-sweet shit smell.

the heavy rain and wind may have flattened their leaves but the flowers still stand straight and look as if they have another week or so of flowering.

the orchid I noticed last year is still there – two plants – is that more than last year? I must check last year’s blog.

back in the workshop, door open to the sunshine yesterday – not today in the rain and wind – I have been working on new things, and new old. six years ago I made three of these islamic ewer shapes with a four part base and a square foot, and I sold them almost immediately. after that I went on to making three part bases, and finally spherical bases made with press-moulds, but I never felt any of these were as successful as the originals. they are not easy to make – the neck/spout has to be light, or the base collapses; after a few false starts I have a strategy worked out and have five ready for bisque. the two oval dishes are made from the same template as the big new shaped bottles, and are a further development of the circular ones I made in january and february.

then little beakers, which I want for Hatfield. the dark grey clay is a sculptural clay full of molochite grog sold as pizza oven clay. it is okay as long as it hasn’t lost a critical amount of moisture; yesterday I had to wet it repeatedly with a sponge as it dried too quickly … clay doesn’t like that sort of treatment, so the pieces I made were much more cracked than sunday’s efforts. I have studded it with broken up dried porcelain, rolled into the slab.

Dameon Lynn kindly brought me some clay his neighbouring farmer had dug up – it’s fenland clay – riverine – all black with anaerobic life and smelly – black mud just like the saltmarsh, so I am trying it as a slip.

over the off-white stoneware clay …

I brushed it on with a big chinese brush and scratched lines through it. it will be interesting to see how it works out. it fires pale orange at 1000 C; that will darken at stoneware temperature. I will put it on some bits and pieces for glaze tests.

yesterday I was very optimistic and put in four rows of carrot seed, also some more salad greens

I am eating the thinnings of the first lot of salad sowing, in the mini-poly-tunnel. I have another polytunnel for the second lot – partly to discourage the rabbits – I have seen young rabbits in my garden a couple of times …..

here is a bed of love in the mist and cornflowers and a few wildflower annuals

the beauty of bath has all its blossom out, but there are very few insects to pollinate it. yesterday I saw a comma and an orange tip – this time last year orange tips were everywhere, and the jack-in-the-hedge they love had been up tall and flowering for weeks … this year it is not at that stage yet.