Handbuilding Techniques: The Slab Method

The Assignment:
To create three pieces using the slab method: one soft slab, one hard slab, and one raku.

Each handbuilding technique has its benefits and downfalls. All of the methods have a potential of giving beautiful circular shapes, however, only the slab method can produce a sharp corner. This is particularly true of the hard slab method. Like all slab projects, the clay is first rolled out to a desired thickness (1/8-1/4 inch), and then the potter cuts out each component of the shape, lets it dry to a leather hard state and then joins the pieces together.  On the other hand, one can use slab in a more free-form way, by using molds. This is called soft slab, in other words, soft wet clay that is able to take on any shape. A mold can be anything from a bowl to a cylinder or even a cone. The potter simply places the clay onto the desired mold and then lets it dry to a leather hard state before taking it off, allowing the clay to take on that same shape.

Soft Slab

Soft slab is my least favorite method within slab handbuilding, because of the obvious lack of control over the shape. So for my soft slab assignment I decided to go with a bowl shaped mold. Since The bowl shape tends to be very sturdy in the firing process and doesn't warp as much at high temperatures, I went as thin as possible for the walls. I rolled out a large slab to an 1/8 inch thickness, draped it over a newspaper covered bowl, and then folded the walls in over each other, smoothed, and curved them in to create a twisting drapery effect on the sides. After it became close to leather hard, I took it off the mold and smoothed the inside of the bowl.

The glazes I used for this piece were:

•  Oil Spot Black for the inside of the bowl and
• Weathered bronze with Honey on top for accent

Hard Slab

Since the hard slab process requires to work with leatherhard slabs most of the time, it opens up many different design ideas. I decided to put some carving action into this piece. At first This piece was going to be a vase, but I got the idea to carve designs in the body from  this video of Bill Finley's ceramic artwork:

I started by rolling a piece of slab onto a cylinder pipe, and then carved designs into it while the clay was still wet. Once the clay became leatherhard I took it off the cylinder, and added the top and the bottom, which were both thrown on the wheel. Then I smoothed down the edges and sanded down the whole piece once it was bone dry. Honestly, I fell in love with the idea of carving that I made two more similiar vases. The first vase became warped because it was made a little differently. Instead of carving the designs into the body while it was still on the cylinder, I did it after. Thus creating a huge impact on the body while I tried to carve in the designs.

   



When it came to glazing these, I liked the idea of contrast. I also tried not to distract from the beauty of the designs by using matte glazes for the bodies. For my first vase I used:

• Fake Ash
• Oil spot Black



For my second vase I used a turqoise matte along with white, However, for my third vase, below, I used the same glazes that I did for the slab bowl. Put a candle in one of these in you get a latern that will shine the designs onto the walls around it!

  

  

 

Raku

There is beauty in the process of raku, the beauty of the unknown. One can do all he or she can to control the process but in the end it is always unpredictable. Raku is a low-fire process in which the potter heats the clay pots in a kiln, then takes it out when it is a glowing, bright red and puts it into containers full of ignitable material such as paper or leaves. Once the material catches on fire, the lids are closed in order to cut off the oxygen supply, creating an extreme reduction atmosphere in which vivid metalic glazes and crackling is possible. Western raku was adopted from the traditional Japenese raku firing. It is usually done outdoors, due to the excessive amounts of smoke and ash and is a fun way to spend a cool spring or autumn day. Below are some pictures I took of the process:

For my Raku piece I decided to make a slab vase as well. I first started by cutting out patterens for the individual slabs: a long trapezoid for the sides and a square base. Once the clay was close to leatherhard I scored slipped and attached all the pieces together. Then I threw the top part on the wheel, scored, slipped, and attached it to the slab body. To finish it off, I trimmed off all the excess clay.

Due to the extreme temperature changes and rough handling of the raku process, clay bodies are subject to a great risk of falling apart or cracking. This is especially true with raku slab pieces. Unfortuanately, my vase didn't survive the raku process in whole, but I succeeded in gluing all the fragments together with Epoxy.