I was worried about trying to make a complex slabbed form in porcelain. I was most worried about the slabs getting too wet or too dry during the making of the piece. With fifteen slabs I wanted them to stay as close to the same condition as possible until the pot was complete, especially the base. I wondered whether I should try to make it in two halves, keeping the other half under cling film, so before starting I tried a couple of tests on a hexagon, and found that it is better to add one slab at a time than to build separate halves, and building without a clay base is not a good idea on more complex pieces. It seemed that I would have to make the porcelain pot in the usual way.
I had a number of issues, as follows.
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Slab roller - The first issue related to rolling the slabs, I used porcelain for the first slab, and rolled it too thin, it was difficult to get it off the cling film. I then tested a stoneware slab on the grey cloth until I found the right thickness. I went back to the cling film and the porcelain cloth, but the porcelain slab was thinner than the stoneware one. I am not sure why this happened, perhaps the stoneware clay was not as soft, or it had grog in it? I would not have thought the clingfilm had much effect on the thickness, but I need to look at this again. The thin slabs would cause problems late on.
Cutting and scoring the clay - The second issue is the time it takes to cut and score all the slabs. It takes a long time, and you don't have that with porcelain. When first cut the porcelain is very soft, but it dries quickly and each piece needs to be completely covered or it dries too much. It took a long time to prepare the pieces, much longer than with other clay bodies, because of the need to keep the porcelain covered. This extra time meant that I did not have time to prepare and make the pot on the same day, which was not ideal.
Drying - The third issue was that pieces did not dry consistently, some needed to be sprayed, others needed further drying. The drying time is so quick with porcelain, it was difficult to manage. In the end I dried some on newsprint and others on plaster to try to speed up the slow-drying slabs. I need to work out how to do this better. I saw a video of Justine Allison, she dried her slabs on newspaper after scoring. The number of slabs I was trying to join added to the problem, I need to try again with fewer slabs and build up to a more complex pot. I think the success of the test pot went to my head.
Marks - Fourthly, it is fiendishly difficult to stop the porcelain from picking up marks. I washed the boards and tools very carefully before I started, but I still picked up marks from them. Having tried to remove the marks from the making, I then picked up blue marks from the damp paper towel I had put around the rim, to stop it drying before the rest of the pot. I switched to a white antibacterial wipe washed under the tap, time will tell on that one.
Finishing - Finally, I managed to join the fifteen pieces, but some of them had marks, or texture from the slab roller cloth. It was extremely difficult to finish the pot as it was so fragile. I tried my best to sharpen the joins and smooth the sides. I decided to try to turn it upside down on a cushion to finish the joins at the bottom. This seemed to be working, until the pot fell over onto its side, opening up several of the joins and distorting the panels. At this point I didnt know whether to continue or recycle the whole thing.
I decided to try to put the joins right, and dry it very slowly. I managed to get a dry pot without visible cracks on the joins. The top was a bit uneven, but I decided not to risk touching that as it was very fragile. It has gone for bisque firing.
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