Stoneware mugs

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I’m really enjoying the challenge of throwing on the wheel. I feel I’ve come a long way since beginning the course in September – I can now control the clay to a degree and make the shapes I want which is new and exciting for me. Most of my last term was spent practising to throw cylinders which was a struggle because the clay is determined to flare out at the rim (hence why most teachers encourage you not to begin with making bowls).

These mugs are slightly tapered cylinders with pulled handles (attached when the body was too dry – there are cracks at the joint).

To decorate I played with layering a couple of glazes from Stephen Murfitt’s ‘The Glaze Book’ – an opaque yellow green and pale satin grey/green. At the moment I am brushing on glazes and making up small batches (100ml) but this is causing very uneven layers of colour. I might choose a couple of glazes I really like and make up a bigger batch so I can start dipping and get a more even coverage.

I don’t feel I’m very good at harmonising form and decoration. My approach has always been ‘more is more’ but I’m going to challenge myself to spend less time decorating and see if I like the pared-down results.

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Raku Friday

Phoebe and I fired a raku kiln together yesterday and I put in a couple of my thrown forms. The first is a white st thomas ‘moon jar’. The duck-egg blue raku glaze came out a bright light blue with crazing however the stoneware reduction glazes I applied came out a rusty colour from the red iron oxide and a matte dark green, possibly from the presence of copper carbonate. The earthenware cream glaze inside came out a much brighter colour because it matures at a lower temperature. The effect looks a bit like an abstract upside down landscape or a globe. We left the pots in the flames for 1 hour 15 mins then placed them to smoke and reduce in sawdust, shredded paper and hay for 1 hour. To get even temperature around the kiln chamber I’ve learnt to cover the top on the side which is coldest with a piece of kiln shelf as this adjusts the air flow.

The rounded form was inspired by the work of Adam Buick although I’m struggling to make perfectly spherical shapes. It’s clear from these photos the footrings on his are a lot narrower than the top which elevates them. This article has a little information about moon jars and their contemporary re-interpretations.

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Adam Buick at Collect ’17

Inspired by Cait’s sake cups from the Pottery throwdown on Thursday I tried wrapping copper wire around this mug (reduction st thomas clay). The surface is painted on duck egg -blue with lines cut through sgraffito style with a needle point tool. I like how the glaze has blistered and crawled dramatically on the side exposed more to the flames in the firing. The copper wire turned black and fused somewhat to the glaze but other than that didn’t leave any trace. It was interesting to watch Hannah from L5 spray alcohol onto her vessels to create varied surface colours. I’m going to try and get hold of the Lark ceramics book ‘Alternative kilns and firing techniques’ from the library to find other raku firing techniques to try.

Reduction Firing

Last week I had the chance to fire some work in a gas kiln for the first time and the results came out today. I don’t know much about how the firing works except that the kiln chamber is starved of oxygen so oxygen is taken away from the metal oxides, but I’d like to learn more. I’m attracted to the unpredictability of the glazes in this kind of firing.

I’d prepared two reduction glazes -the first was a Crystalline pale yellow/green semi-gloss with slight speckle (1280-1300C):

Feldspar                                 37
China clay                              18
Whiting                                   15
Quartz                                      10
Lithium carbonate               9
Titanium oxide                      9
Copper carbonate                 1
Zinc oxide                               1

The feldspar I used was potash and I added Titanium dioxide as a substitute for Titanium oxide. I’ve decided to use small thrown (off the hump) vessels or sections of discarded pots for glaze tests from now on because flat tiles can’t show how much the glaze runs.

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Crystalline yellow/green on Reduction st Thomas

The second reduction glaze I made was a Chun type pale green glaze with crazing:

Potash feldspar                                  45
Quarts                                                    25
Whiting                                                  17
China clay                                              9
Bone ash                                                 2
Dolomite                                                 2
+ Red iron oxide                                    1

The colour was subtler than expected but I like it’s fresh, quiet quality. I find the random speckles of dolomite glazes like this one attractive.

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Chun type green on Reduction st Thomas

Below: Buff stoneware. Two layers of Crystalline yellow/green glaze on outside with Duck egg blue raku glaze circles and Chun glaze inside. I like the roundness of this mug’s base in contrast to the sharper cylinder forms and the pulled handle balances it well.The ribbed texture from drawing up walls inside the form is highlighted by the way the glaze has pooled and draws attention to the way the mug was made on the wheel.

Reduction st Thomas. Duck egg blue raku inside and outside painted with crystalline yellow/green with chun type on top. Painted lines in red iron oxide. The duck egg raku glaze turned out a stunning, vibrant matt blue, I only wish I’d applied it to the outside.

Reduction st Thomas with blue slip splattered on top before bisque. Chun type green painted on outside with red iron oxide lines and turquoise spots. Inside crystalline yellow/green. I enjoy using the surface of vessels as canvases to explore abstract application of slips and glazes. This layering means I get exciting and unexpected results each time although I have to document carefully what I apply.

Buff stoneware cylinder. Inside turquoise stoneware glaze. Outside crystalline yellow/green with duck egg raku over bottom half which has created a cloudy, lichen-esque pattern. Red iron oxide details. The turquoise stoneware glaze turned an almost emerald green and had a bubbled texture.

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4 layers Transparent green stoneware glaze on RsT

 

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Chun type green over crystalline yellow/green

Update: The kiln should have fired for another hour because the cone fell over instead of bending so didn’t reach optimum temperature. The glazes have been underfired which may explain why they didn’t flow much and why the raku blue was so vibrant.