Using Slip Casting, Handbuilding, Press Molding and Throwing Techniques to Create Complex Sculptures

Ceramic artist Valerie Zimany shares her process for combining cast, thrown and handbuilt parts.

When One Technique Just Won’t Do

Today we are giving a sneak peek of the upcoming November issue of Ceramics Monthly magazine, which features ceramic artist Valerie Zimany. Readers of Ceramics Monthly might remember Valerie’s work from the 2008 Emerging Artist issue back in May. Valerie creates her abstract ceramic sculpture using a variety of techniques and she explains those to us below. She also shares her a recipe for a “super-stick-em-up” slip, which really helps in assembling her complex pieces. – Jennifer Harnetty, editor.

In my work I utilize a combination of slip-casting, press-molding, hand-building, and throwing techniques. For slip-casting, I rely on porcelain for its translucency and ability to retain fine details.

Once molded, but while still pliable, I manually alter the forms by bending, twisting, and shaping. Some retain the details of their organic or plant-based origins, while others are sponged or sanded down until the original has become completely abstracted. The cast parts are then attached to, assembled in, or stacked on other parts, bisqued and then glaze fired.

These works generally fall into two categories, those formed in saggars (protective clay structures), and those that are combined with wheel-thrown or hand-built elements. The saggar forms, which reference Japanese ikebana in their formal structuring of line and volume, are cast bone china that will often not survive handling until final fired to a high temperature.

In response to the saggar-built forms, I also began combining the castings with wheel-thrown vessels, loosely taking inspiration from Japanese bon, or the legged serving trays used in formal kaiseki cuisine. Through their gesture and arrangement, these forms have become more animated – lurching, tip-toeing, or strolling in their implied movements.

Casting Slip to Stick-Em-Up Slip

1. Pour desired quantity of prepared, fluid casting slip into a mortar and pestle, or other suitable container (such as Tupperware and spatula/spoon).

2. Using a syringe or eye-dropper, begin adding flocculant to the casting slip a few drops at a time – i.e. use Epsom salt solution (made by dissolving Epsom salts in water until no more dissolve and crystals form on the bottom), or a commercial glaze suspender such as “Flocs”.

3. Mix the casting slip with pestle while continuing to add flocculant. The slip will begin to thicken dramatically.

4. Stop when the slip has reached a sour-cream-like consistency.

5. Wet down a handful or two of toilet paper in a different container and mix until fibers separate.

6. Strain out approximately 25% of the slip’s volume of toilet paper fiber and mix into the stick-em-up slip.

7. The stick-em-up slip is now ready to use, and is advantageous over a simple clay and water mix because the base utilizes casting slip (low water to clay ratio = less shrinkage), is durable in the green state (because of the added paper fiber), and will have a slight melt when fired giving a strong attachment

To ease assembly and minimize cracking, I use the same porcelain body for hand-building, throwing, and casting. This insures the shrinkage will approximately be the same overall, resulting in a lesser rate of cracking, but I avoid taking chances by not joining parts of too widely differing thicknesses.

I also work while most parts are at roughly the same level of dampness – not always easy to do when using multiple forming methods, but I keep things at a fairly even wetness with a variety of wet-boxes to store the cast, thrown, or hand-built elements until I am ready to use them. When joining parts I thoroughly score the surface and use a very thick, dense stick-up slip fortified with paper fiber. Finally, when a few works are complete, I allow them to dry very slowly over a period of 1-2 weeks. Rather than arresting the dry rate with plastic (which can form condensation), I use sheets of thin cotton fabric to gently dry the work and bisque on a very slow cycle, often holding at just under 200 F for 2 – 10 hours depending on how large or thick the work may be.

While in Japan, I used pugged local Kutani porcelain that was commercially available and fired at about cone 8-9 in oxidation or reduction, but since returning to the U.S. have re-adapted to a cone 6 porcelain that was commonly used in Ceramics at UArts.

Note: Due to the paper fiber content of this slip, only mix in small amounts, otherwise it will mold and rot if stored for long periods of time!


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