Using string and various rods to create dippable, deformable supports ceramic slip trailing

A TACTILE GEOMETRY

String can be used to form tensile structures when wound around rods, leading to anything from geometric patterns to free-form organic nest-like patterns. I started to ask myself whether those patterns could be captured in clay. Ceramics artists have already been dipping combustible materials in clay slip and firing them, so why not try these rod-supported patterns? Here's the process I've found so far using combustible or removable supports and filaments, plus wet or thickened clay slip. I'm sure this can lead to many flat or dimensional patterns that would otherwise be more difficult or impossible to create.

DIVERSITY OF PATTERN

The structure of the final piece has many contributing factors. As much order as there is in the rods, and method of string winding, there is still much improvisation about where the slip goes, and what happens to the system after it sets up. For me, this is a perfect example of combining intricate predetermined string patterns, yet leads to distorted, organic liquid clay slip forms.

What follows is some recent progress with strings wrapped around metal nails or plastic tubes, which are then dipped in clay slip or used as 3D slip trailing meshes. Some of it is interesting, and some of it...well, to put it kindly, some of it needs more work to become useful.

ZOO OF FINISHED RESULTS

A range of ceramic pieces has been made, with varying degrees of success. The scaffolding itself has already gone through a number of iterations. Admittedly, there is more work on the tools than on the finished pieces. But this won't come as a surprise to anyone who knows me. If you see a form you like, you can read below about how it was made.

Slideshow of various results from string used as container and manipulator of wet clay slip.

A FEW VIDEOS AND CLIPS

Along the way I make little videos of things I want to remember. Take a look here to see some of the action.

This video shows tool making process for a plaster dome that has many holes in it for securing nails. These nails will be used to hold woven strings, that in turn will be used to shape liquid clay slip as a experimental ceramics technique.

The dome in this video is shown as the large dome with holes.

Two circular rings of nails hold two types of string: a heavy twine, and a thinner kitchen string. The nails being pulled are holding all the strings in place while wet clay frosting settles inside. After this video was shot, the string form was distorted, taking the clay with it.

The inner lining was so thin to begin with, that after stretching it was in tatters. But since the layers were close to the stronger outer layer, they held on. Looks like tree bark.

This form is shown as finished in the gallery above.

After the last two nails are pulled out, the knotted twine wrapping is distorted by hand, changing the clay slip inside into a wonderful gnarly shape.

The piece resulting from this mesh is in the gallery above.

In this low-tech 3D printing technique, I weave coarse twine around wood dowels to form two rings. Then, thick clay paste is dispensed inside. After it dries a few minutes, the wood dowels are removed, making the string weaving floppy. The clay is distorted and changed by the movement, and becomes an interesting finished piece of sculpture.

The resulting piece is shown in the gallery above.

The spirit is willing, but the flesh is weak. Or, really, the clay slip was weak. After the piece dried, and was fired in the kiln, the stresses in the clay matrix were too great and the parts cracked. But the pieces were so very interesting.

The shattered pieces from this form are the white bits with holes and jagged edges.

Since everything is based on spinning, why not use the wheel to make circles on a hand-sculpted bowl while it's upside-down? This form will become a mold for plaster.

This dome is one of three shown that get stabbed with red straws, then filled from underneath with plaster.

 

SCAFFOLDING MATERIALS SUMMARY

There are many ways to build an array of holes in a material, but I opted to start my exploration with a hoop-and-tape method, and progressed into plaster. The key feature to these methods that I find useful is that I don't need a drill press, even though i lose out on a little accuracy. As it happens, accuracy of rod angle might not be important.

ARRAY TYPES

Hoop and Tape: Not bad for a hack!

I started by wanting a round array of rods that would eventually lead to container type objects that you could drink from or plant in. This was my first solution. It works pretty well! The tape loosens as the winding gets taller, creating a fish-weir type shape at the top, unless you add some spacing elements. Here are two windings on such a base. Different store-bought hoops are different enough in diameter that using two adjacent sizes leaves enough room in between for a thickness of slip that is strong enough to hold up after lots of distortion.

Single round array from embroidery hoops. Rods held with tape.

Hoop and tape form showing a particular winding that makes a smoother string surface on the inside of the rods. The windings develop in many ways with respect to whether the rod bump is involved in the casting or not.

Plaster: A bit fancier!

The plaster bases that hold the rods steady seems like a good development. Here are examples of early stages. The plaster bases themselves are interesting to make!

Round array made of plaster. Holes are about 1/2 inch deep to accept rod material.

Square array made of plaster. Holes are about 1/2 inch deep to accept rod material.

Example of using plastic embroidery mesh to align nails vertically in concentric circles. The space underneath where the points are represents the part buried in plaster. No drilling!

Nail holding apparatus just placed in wet plaster measured to exactly the correct depth.

Several clay dome shapes with lines drawn on outside to indicate to me where to drill the holes. Unclear yet whether these subtle changes will matter after all is finished. But I could always make these as just normal ceramic bowls!

Example of the clay and straw pattern that will eventually become a plaster dome that holds nails for winding the strings that support the clay slip.

Interior of plaster dome forming bowl. All these ends of coffee stirrers will be completely enclosed in plaster, which eventually is used to hold nails. Conveniently, pushing the straws through the clay wall left a little plug of clay on the ends, which prevents most of the plaster from draining out.

Unmolding process of plaster dome form. Clay form was sculpted for pouring plaster inside. Lines were drawn on outside of clay bowl for locations of red coffee stirrers to push through. These red pieces are encased in plaster, but pull out, solving the problem of my not having a drill press. Here, the wet clay bowl form is being dismantled after the plaster has set. The metal nail is shown here as example of the radiating angle all the holes have.

Large plaster dome form with different hole spacing in different areas.

Plaster dome shown here with all its stirrers pulled out. Smaller dome in back, made in similar way, shown with all holes filled with nails. This would make a very complicated winding. Much more likely to use a few nails in a simpler pattern.

TECHNICAL COMMENTARY

• Array material: Plaster instead of wood
  • The process of making the supports is almost complex enough to warrant its own blog entry. But the summary will do fine for this explanation: Plaster has many uses in the studio and I felt it was convenient to use as the support material for the rods. 
  • Wood is plentiful and easily worked, but I wanted not only flat panels but also curved ones. And besides, my clay shaping ability is greater than my wood shaping ability.
  • Holes would typically drilled (and be more accurate!), but, instead I arranged the rod materials how I wanted them and poured plaster around them.
  • Hard material supports rod materials in a regular pattern or array for weaving the strings. First pattern choices were circles in concentric pattern, and squares or rectangles. Next patterns were more detailed arrangement of points.
• Rod material: nails, wood skewers, coffee stirrers
  • Metal nails are useful because they're smooth enough to pull out of the looser string windings, and rigid enough to stay straight, if winding needs to be tight. Metal nails rust and give bits of red color to my clay, and can be difficult to remove if the clay dries on them. Nails come in standard and convenient lengths, but I'm not cutting them down at this time.
  • Wood skewers are easily cut to different lengths and are somewhat consistent in diameter. They can be burned out in the kiln, but I haven't tried that yet. The bamboo type carry splinters which can make pullout difficult on the thinnner, multistrand strings.
  • Coffee stirrers are very easily cut, give no pullout resistance, and don't add mineral color to the strings or to the slip. They are flexible at full length, so the winding might become distorted from its planned shape. They would burn out, technically speaking, but I'd rather not. Fortunately, they're easy to remove or trim off excess. This particular brand fits snugly around the nails, so occasionally I'll need the nail to be protected from the strings. I might use the nails always covered with stirrers.
  • FUTURE rod materials include stiffened clay rods, thin kiln-stable wire, pasta.

• Wrapping material: String of various weights from twine (thick) to thread (very thin)
  • Thread and string are useful when wrapped in close-spaced parallel lines, for presenting itself as a flat enough surface for slip trailing. Can easily be moved aside to trail slip through the surface rather than onto it. I haven't burned out any of the thinnest thread yet, but I'm guessing it leaves a tiny hole.
  • Butcher's or Kitchen String was good as a space-filling strand, but didn't seem to attract the quick connection to the slip. Tiny amounts of slip actually just slid off the string. Future use will involve pre-watering the string to get a better adhesion from the slip. The string was easy to remove, if it did not get too embedded into the slip during distortion.
  • Twine was interesting because its furry texture helped hold slip where it was deposited but also gave more texture after firing. That furriness made it a little harder to remove from the stabilized or dry piece, but presented no real problem. Burnout was complete enough with only a little easily removed ash.
  • In similar situations on pottery shapes already made,  flexible string can be used to lay out patterns around the curved surface of a piece of pottery. In this way, the string is only playing a textural role, since it cannot support itself.
  • Being generally absorbent, string woven onto itself or wound around rigid rods is structurally-sound enough to hold up under a quick dip in slip, and thus to absorb enough water to leave a coating of slip on all surfaces of the string. After the slip dries, the whole thing can be put into the kiln to permanently set the ceramic and burn out the string at the same time.
  • The resulting pieces have capture the string's texture when woven or wrapped around nails, but show how that detailed original form gets distorted into more organic shapes. The early part can be mostly reproducible, but the later part definitely resists repeatability.

• Clay materials: SLIP
  • The clay liquid is called slip and comes as a slippery, flowing liquid. This thin nature can be adjusted to a thicker consistency with a few drops of vinegar. I use thinner and thicker recipes in the sculptures shown here.
  • When thin, the slip can flow into absorbent things and, when thicker, create a coating on anything that's dipped into it.
  • For these sculptures, a variety of string materials can be used to make unique forms, or a greater number of production forms.

PROCESS SUMMARY

The process for setting up the winding for dipping or trailing isn't too involved, but I admit there are lots of details. But since I enjoy them, I have to make sure I am aware which ones make a difference in the final object and which are simply "recreational" detailing!

• Pick pattern of rods among all the empty holes.
• Choose rod material.
• Unwind strand element and begin winding around rods.
• Choose clay slip color and begin applying slip into or onto the strand mesh.
• Alternate adding more windings, then adding more slip, until form is finished.
• Allow clay to settle from fresh, or even longer to actually dry somewhat.
• Remove any rod materials that must not go into kiln; remove any remaining rod materials that are convenient for distorting.
• Remove any strand elements that must not go into kiln; remove any remaining strand materials as is convenient.
• Allow sculpture to dry and finish the piece by baking it in kiln.

ASSORTED PROCESS PHOTOS

I admitted earlier that I love the problem-solving process so much, I might even like the tool-building more than making the finished pieces. Here are pictures of various aspects of the development so far.

Pictures relating to the round grid plaster form. The plastic mesh is standard embroidery mesh found in craft stores.

PIctures here show the smaller dome form I made first. Lines around the surface guide me to stab with cut up coffee stirrers to make the holes.

PIctures of a larger dome form, with more elaborate holes pattern. The plaster filling was shot as video because it was just too pretty to pass up. The video is in the section above.

Here the coffee stirrers are used as verticals. And since I got tired of wrapping the thread around each and every vertical support, experimented here with wrapping only around key points in the geometry, and simply passing over the rest. Seems to have worked. Note that in the last photos, the slip was still wet when the supports were lifted out of the holes in the base and tilted to distort the mesh. I find this very exciting.

Here are shots of the rigid string mesh that, unfortuntely or fortunately, resulted in lots of little mysterious cracked clay pieces. The solution may be to add even more paper pulp to the slip mix, or to use flexible rather than rigid verticals. Or some other thing entirely. But I'm certain that come combination of factors will allow me to wind a string form and dip it and have it survive the firing.

SO, HOW DOES IT WORK?

SURFACE TENSION  A key factor of this process is the fact that close spacing of taut parallel strings functions as a solid flat object with respect to the thickened clay slip. The apparatus that holds and releases the string is comprised of metal or wood rods for winding, and plaster for ordering the array of rods. The apparatus itself is reusable, and is made from a handful of easily-obtainable materials.

This modular system allows the rigid supports, and thus the string, to be used first in a deterministic way while the supporting parts are highly constrained, but allows for secondary structural changes to those same unsupported parts while the clay is still wet. Additionally, the supports can be made from combustible materials, so that removal is not always necessary.

At fairly low amounts of distortion of the string form, the strings contribute surface texture to the clay. Major distortions of the strings drastically change, and support, the overall form of the piece. Strings can also be an embedded, combustible core to dipped forms. For needed support, strings can be woven around other objects such as nails and wooden rods or coffee stirrers. This system of winding allows any non-combustible rigid supports, like nails, to be removed while the clay is at any stage. Nails and metal rods, for example, are useful because they are strong, but cannot typically be burned off in the kiln. The wooden supports, however, present no special problem in terms of firing procedure, and can be burned out, leaving behind clay structure.

Regardless of support type, the strings form clay indirectly as a source of texture, or directly by being coated by slip and burned away in the kiln. The flexible string is wound around any supports, which in turn provide a rigid enough structure for liquid to be contained. As the clay slip thickens and dries, it becomes more and more self-supporting. At different stages after the clay is self-supporting, the external supports of string and non-string elements can be removed. The form is either allowed to dry without changes, or can be further changed by manipulating the laminate created by the alternating, deformable layers of string and slip..

Artistically, the strings can be wound in many patterns that will be transferred to the clay. I've barely begun the search in this particular direction. 

THAT'S THE SHOW FOLKS

Now I go back to work. Refining the patterns in the strings and the liquidity of the slip so that larger forms can be made. I can't wait!

Using newspaper and pleated copy paper to cast new clay shapes

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.

Two versions of the tray form, showing the undulating edge effects that happen automatically.

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.

Paper folded shapes intended to make a hollow, star-shaped extrusion. Paper immediately softened, buckled outward, and leaked downward into sand catch basin. But not all was lost!

“I’m exploring methods of making objects that make explicit the distinction between an object that was made and an object which happened. The work is sometimes clear. The work is sometimes interesting. My work is always at risk of overstating what could instead be implied. My work is always at risk of enunciating clearly something that makes no sense regardless.”

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:

1. I couldn't figure out what to do with the failed paper form
2. 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.

Clay form made from the collapse of a star-shaped, paper tube, pleated for strength, but not enough!

Detail of the very thin and beautiful membranes of clay that appeared as the clay drained out of the paper form.

“Work which happens once can happen again, and the connection to manufacture is important aspect of leverage for me. If something can happen more than once —if I can set up the situation— then it proves my intent. A philosophy has been established. Manufacture does not have to look a certain way.

I’m exploring the idea that something liquid might still be folded. This is subtly different from folding something and pouring liquid into it. I like both; I’m trying harder for the former.

I’m exploring the idea that edges are not made but happened. This will at first look like something has been broken, or broken off. It may or may not fit with our idea of finished product. Yet, is this not what we’d see through the microscope of any object we find in the natural environment?

I’m exploring the idea that the concept of manufacture need not dictate style. I’m making systems that are definitely —at least theoretically— as repeatable as any other, but with outcomes that look natural, or broken, or generative.”

This is the back of the form, showing some of the sand that is embedded in the clay surface. The edges are sharp and remind me of flower petals.

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.

The entire shape. Look at the tiny bits of clay that flowed along the sides of the large pleats, seen to the left in the picture.

“As makers we progress from set-up through “sufficiently final” result. How much are we involved in those stages? Can we argue convincingly for those times we deliberately invite random effects? How do we argue for our authority in such chaotic systems? Is this artifact the result of a process, or philosophy, or both?

Our liquids flow then harden. Our wet powders dry, sinter, melt, and cool. Our hands obey and rebel. The artifacts never lie, but never tell the whole backstory, either. I am interested in making more of the process visible, to make the backstory explicit, to make a convincing argument within the piece itself that this choice was made over that one. I won’t always be around to explain the work, and so it must take care of itself.”

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.

“PAPER TYPES HAVE CLAY IN THEM
Newspaper has almost no clay in it, and so burns away at 1900 degrees Fahrenheit with very little ash. The copy paper I used, however, has more fine clay in it so that it is smooth to print on and write on. That paper was used for the pleated form, and there was much more ash to wash away.”

Clay slip with a lot of sand is spread like frosting on a single sheet of newspaper.

Newspaper on top and bottom of wet slip. Grey foam rectangle placed in middle. Edges of paper cut and folded over foam. Note that layer of paper closest to foam extends further inwards than outside layer of newspaper.

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.

Several views of the envelope-like piece

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.

Stabilized forms with foam support removed, most of paper removed. Ready to dry out for kiln.

Trussed shape with tape. It mostly worked.

Fired form, all paper burned away, leaving many interesting folds and curves where the paper turned on itself and where the tape held the shape less flat.

Better view of interior and folds at narrow edges.

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.

The clay slip is inside the outer sleeve of newspaper, where the darker, wetter area can be seen. The rubber band is holding the layer shut, but also adding its own wrinkle pattern to the paper and clay.

The tube itself has paper on it to enable the clay sleeve to be removed when it is stabilized enough to hold its shape. Removed too soon, the clay form will slump into something less round. Removed too late, and the clay shell will crack from shrinkage around rigid tube, or careless flexing movement.

Good view of the rubber band tightening around the form, leaving marks in the clay.

The tubes kept their shape perfectly, but the reason this one doesn't curve all the way around onto itself is that I broke off a part earlier in the process removing the newspaper. Ironically, since the edges on these forms are all atypical, the broken edge doesn't call attention to itself.

Of all the results in this series of experiments, this edge quality is almost my favorite. Smooth parts next to rough parts, hollow cavities that go down into the wall. The rough quality is the sand mixed into the slip. And all of it almost completely automatic. 

Another view of my favorite edge effect. This tube is completely enclosed on itself. It is not connected at that overlap because paper was between the clay layers. If this piece were glazed, the glaze would fuse those edges together for stability.

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.

The orange-brown angled form underneath is just another clay box I built. Here I'm using it to hold the wet clay layers in an overlapping position until they dry enough to stay there.

The completely fired bowl form with cut overlapped edges easily seen inside and out. The upper edge of the bowl is unchanged from the edges that happened when the slip was spread on the newspaper.

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.

WHAT'S NEXT?

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.