A Complete copy of the journal article. More paper clay articles here.
THE MAKING OF PAPERCLAY PORCELAIN BANNERS
By Steve Harrison
Paperclay can be used to make sonic excellent tiles. Very thin and translucent porcelain paperclay tiles, or what I call ceramic banners, can be made up to 900 x 600 mm, by 1 mm to 1.5 mm thick. Yes, read my type, 1.5 mm. thick! using the following recipe and technique.
The standard translucent porcelain bodies I found to be disappointing and did not work well. So I developed the following body specially for this purpose. Having tried many different variations, this is the most successful recipe so far;
Plastic White China Clay 1500 g
Nepheline Syenite 1500 g
Ceramic Fibre (100OoC) 250 g
Fine Paper Pulp (dry) 500 g
Water 4.5 litres
The china day I use is 'clay ceram', and the ceramic fibre doesn't seem to matter, I tried all three grades and couldn't notice any difference between them, so I use the cheapest which is 1000'C L T Batt. The paper pulp is a dry shredded material used for home insulation. I bought this from 'Cool n Cosy' home insulation in Sydney. There are two types, The finished product has poison added to deter rats etc. for use in houses, but it is possible to obtain untreated material before it has gone through the final process.
Measure the water into a plastic bucket, weigh out the ceramic fibre and dunk it into the water. Because this is a clay making exercise, you will already be wearing your dust mask, but rubber gloves are also advisable when handling ceramic fibre. Lift the ceramic fibre out of the water and tear into small shreds, dropping them back into the water. Break up the shreds of fibre into a fine liquidised pulp by vigorously mixing with a paint stirrer attached to an electric drill. Now add the finely shredded dry paper pulp, whisk into the finely shredded fibre liquid until all the paper is wet. Now add the clay and syenite, stir until evenly mixed and there are no colour variations. The result should be a soft plastic paste.
Using a light weight cellulose/cement batt as a backing, spread a jumbo
garbage bag over the batt, held in place with paper clips. Spead a layer of paper clay mix fairly evenly over the plastic sheet with a spatula. Place another sheet of plastic garbage bag over the top and roll out the clay in all directions with as much pressure as you can muster until it oozes out off the batt on all sides. Alternatively, the batt can be placed on the slab roller and reduced in that way. Keep rolling until it is as thin as you can get it.
Impressions can be applied through the thin plastic sheet with tools, fingers, and objects or the top plastic layer can be peeled off and marks made directly into the clay surface. The resulting tile or banner can be left to dry slowly overnight or left in the sun and wind in which case it may curl a little at the edges but will be- dry in an hour or two. it can be picked up by its plastic sheet (it is remarkably flexible) and laid in the kiln upside down so that the plastic sheet can be peeled off. It can of course be placed in the kiln with the plastic still attached, and it will bum away during firing, but the gases produced from burning plastic are ozone damaging.
Firing is to Orton Cone 8 in 4 to 8 hours, depending on the decoration. If the marks are many and vigorous, a longer firing is required to stop the tile splitting up along the incisions. This is why the ceramic fibre is added, as it doesn't bum out like the paper but persists. The paper does a sterling job at room temperature of binding the surface together but the tell tale waft of smoke at 250,C spells its end, and that is when the normal paperclay tile will crack if the fibre isn't added, as the fibre remains intact until elevated temperatures resisting any tendency in the tile to crack apart along the stress lines created in the decoration. Eventually the ceramic fibres dissolve into the ceramic body glass, which is created by the high proportion of nepheline syenite in the recipe.
The finished banner is quite fragile if it is only one millimetre thick, which is not unreasonable. When removed from the kiln I strengthened and reinforced it by saturating it with clear vinyl acrylic artists medium and coating it on either one or both sides with tissue paper, again saturated with clear vinyl acrylic artists medium. This gives the resultant finish a remarkable parchment like quality. The surface feel is dry with a hint of absorbency that creates an impression that it will almost stick to your fingers, but it doesn't. A feeling of absorbency from something that you know is vitreous, glassy and translucent, yet can be mistaken for paper in not just look but feel, is fascinating, if not confusing. The juxtaposition of knowledge and perception clashing. What is known to be ceramic, in fact porcelain, and all that that entails, pitted against what is clearly perceived to be parchment or blotting paper is intriguing. This is augmented by the fact that these posters, banners, panels, tiles are quite flexible and can be bent 75 to 100 mm. from their original straight form This can produce a noise that Rolf Harris would be proud of.
What appears to be a rigid and fragile gossamer of mixed messages and perceptions somewhere between porcelain and parchment, as it transpires is a quite flexible entity, which beyond all expectations is remarkably robust. I dropped a piece two and a half metres during hanging at one show and it bounced, luckily having landed on its edge which carried the shock of the impact well. However, one piece was successfully vandalised by a king-hit from a child at another show. I've had my disasters, but after all, its the combination of the tactile and the visual that make this technique so appealing. Its perceived fragility gives it an edgy visual presence but this is eventually tempered by the acceptance of actual resilience. I have made a point of always installing these pieces at chest height so that it will facilitate, even encourage exploration of their qualities.
My thanks to Jane Calthorpe of 'Paperclay Ceramics' for advice and inspiration.
Reproduced with kind permission by the author Steve Harrison (Email 7/10/2001 6:40 pm). The article appeared in a slightly different form in Pottery in Australia, 37, (2) 68-9. 1998.
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