UPDATE: COLOR information happening soon!
A manipulative way to use casting slip: without plaster!
Liquid casting slip made from clay is often poured into a plaster absorbent mold, and then poured out after a thick skin has formed on the inside of the mold. That skin dries out a bit, detaches itself, and is ready to be cleaned up and used by the artist. Molds can become pretty complicated puzzles to build and to use. As much as I Iove designing and using new types of plaster molds, I often explore ways to use ceramic slip that don't involve the plaster mold.
Many people dip combustible materials in clay slip, or pour slip into burnout things, or spray slip, and have achieved wonderful effects.
This essay describes a recent set of pieces that use folded paper and newspaper to hold the liquid slip in a particular shape and lets it dry there. This builds on my interest in paper manipulation, pattern, and generative art. Let me show you what happened.
Pleats and folds: Form #1, The star-shaped tube
The familiar chevron pleat makes a flat sheet of paper able to withstand more pressure without buckling, so I thought I'd try building a tube to hold the liquid slip while a skin formed. I started with a full sheet of 8.5" x 11" copy paper and made 16 creases in it across the wide dimension. This was taped into a tube shape. I added paper rings around the outside and a paper tube in the middle, with the idea that these structures might add support.
I wanted the cast form to have a bottom, but I did not want to build from paper a custom bottom for the tubes. This would have taken a long time. I have used sand as an absorbent bottom-forming substance in the past, so buried the bottom of the paper shapes an inch under the layer of sand. Of the many things that didn't work, the sand-seal worked fine.
The slip was poured between the center circle tube and the star-shaped pleats on the outside. My slip was a little thick and didn't pour very quickly or fluidly. This might be a good thing or a bad thing, depending on the material I'm pouring into. At first I guessed that the thick slip would form a thicker coating, and it did, but I also had a difficult time pouring it evenly into the space provided.
About one minute after the form was filled, I could see the paper softening, buckling outward. Then the slip began to disintegrate the folds themselves and started to leak out the form. At this point I knew it would collapse. So I pulled the paper form up out of the sand, and immediately all the slip drained out of the paper form, which now looked like a soggy, deflated, somewhat folded husk. I should have known! So now two things were going on:
- I couldn't figure out what to do with the failed paper form
- I now had a great deal of slip mixed in with the sand
I kept the paper form and placed it on its side to dry. The result is very interesting and I'm glad I didn't give in to my original impulse which was to throw it away.
I was delighted to see the end result when all the paper burned away in the kiln. There is a clear impression that at some point the form was regular, or at least had several pleats. There is also evidence that something catastrophic happened! All captured in clay. The photo shows still some of the ash that remains of the copy paper. This was rinsed off after the photo was taken.
SOFT FOLDS IN NEWSPAPER SANDWICH
The next set of pieces I made were cast from the slip that leaked all over the sand in the first attempt. I knew that sculptors and potters will add different materials to the clay slip to improve some aspect of it. Adding paper fibers, for example, makes the slip stronger and less likely to warp and break before it is fired in the kiln. Adding sand helps with strength as well. Having stirred the slip into the emergency sand, I had perhaps two cups of slip to experiment with.
The distortions of the newspaper + slip sandwich --or maybe it is a crepe!-- capture much of the soft qualities of the slip without being marred by the touching of my fingers. I am especially pleased that the edges of the slip have been affected by the sliding difference between the two layers of newspaper. The inner and outer layers of newspaper have to travel a certain distance around the foam and so create this organic edge.
The clay stiffened overnight and I removed the foam carefully. I broke a few pieces off the edge by accident. I also removed what I could of the newspaper. The pieces went into the kiln and all the newspaper burned off, just as in the first example the copy paper burned off. The end which was drawn up into a kind of point looks like a dumpling. This would be difficult to sculpt, but here it took seconds. The opposite end was simply folded a few times.
COMPARE TWO TRAY SHAPES
The use of the foam block inside the newspaper-clay crepe allowed me to have a hollow shape inside. The second tray shape had more elaborate folds at the narrow ends. It was also trussed up with tape to help with the flatness I felt was a little boring in the immediately previous form.
TUBE SHAPES, AND MY FAVORITE EDGE EFFECT
Another version of the experiment was not a pleat or tray, but a kind of tube that could one day be modified into a vase or cup. The same newspaper plus clay crepe form was made as previous, but this time was wrapped around a tube and tightened in one place with a rubber band. In the pictures you can see my most favorite part of that style. The edge is very unusual. The edge shows the smooth, uneven sides where the clay contacted the newspaper directly. But inside the edge, where the clay is shrinking and changing shape, you see the grainy lining. This is very, very interesting to me.
TOWARDS SOMETHING FUNCTIONAL
The last example in this series shows the effect of a newspaper and clay sandwich cut in specific places while wet, then gently folded upon itself to fit into a bisqued piece as a former. Like the cardboard tube was the inner former in the example above, the bisque form is the outer mold for this next one. This strikes me as a bit simpler than casting liquid slip into the form, since here I get to use the overlapping shapes as sculptural elements. I see these developing as flowers, in addition to simply geometric forms.
I used scissors to cut slits in the wet sandwich. The clay only leaked out a little bit, and was surprisingly tolerant of being moved around while being fitted into the mold form. As above, the object in the photo has thin unconnected areas where one clay element overlapped another while paper was in between. But if this were glazed to make it functional, the thin airspace would seal up perfectly.
TO GLAZE OR NOT TO GLAZE?
I would glaze these pieces between the thin gaps between overlapping areas, if for no other reason than to make them stronger. For decorative purposes, I might spray a very light coating of clear. I think it would be very easy to make a mistake coloring these the wrong way. I know I already like the dry surface.
I would be much more likely to experiment with colored slips, since the integral color of the slip makes more sense to me than applying some color afterward. There is no reason why the original slip on the newspaper can't be more than one color.
I see the newspaper being printed or painted with slip patterns before the structural coat goes down. This will allow me to use pattern on these distorted surfaces before they are made. I don't see it as fun or interesting to manually render patterns on these types of surfaces after they're formed. Firstly, it's hard to do. Secondly, the many places that can't easily be reached should have patterns, too. If both sheets of newspaper have patterns on them in slip that get transferred to the form, I can get pattern anywhere on the form. I'm looking forward to this.
I plan do more forms which could function as containers for plants or drinking vessels.
But for the moment, I'm pleased with the abstract pleat and tube shapes, and the slightly more functional tray and bowl shapes.