Throwing in porcelain

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Nick’s slab built box with my thrown form inside
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Distorting the inside of vessels

I’m throwing in porcelain for the first time. It’s getting easier with practice. At first I found it difficult to knead when it came from the bag but it softens up as you work it. Centering on the wheel is a challenge as it likes to come off, but perhaps this is also because I’m throwing with minimal water. Porcelain is a thirsty clay but using too much water will make it difficult to control so I’ve resorted to throwing with slip instead. I love the tones of light and dark created through these distorted inside forms but how well the light plays on them depends lots on the environment where they’re displayed.

Nick is going to create a plaster mould which we can sit these in and pour porcelain casting slip into to sit them in flat slabs. I found it more difficult to get expressive throwing rings in porcelain so had to use a stick to push them out. Unlike the stoneware bulging and rippling the porcelain wants to hold its form or just collapse completely, there is no middle ground.

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Collaborative drawing

Above are the results of our discussion with ideas for constructing a kind of porcelain igloo or box which you could go inside (or at least put your head inside). We talked about how sound might be distorted as it moves through the twisted vessel forms and how we could use boxed like the one above as bricks to construct a wall you look through. We recorded the discussions so I hope to upload those here soon.

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Glaze tests – high firing

Tests no.1 and 2 below are the same Blue grey speckle glaze as seen in the previous post with low firing tests. Here I fired them to 1260C rather than 1060C to find out what happened to earthenware glazes at stoneware temperatures. 1 is the glaze on Buff stoneware clay while 2 is on porcelain. I still don’t like the results but maybe this glaze will look better layered with others.

In contrast I really like the opaque speckled green glaze from Emmanuel Cooper’s ‘Potter’s book of glaze recipes’. It has lots of depth on the Buff stoneware (4) and breaks to a warm orange when applied thinly. I like the celadon colour effect on porcelain too (3).

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Opaque speckled green stoneware glaze (1200-1220C)

Clear transparent glaze base:
Standard borax frit                         30
Feldspar                                             25
Calcium borate frit                           5
Ball clay                                             20
Flint                                                    20

with addition of :
Tin oxide                                          5%
Copper carbonate                          1.5%