How to Use Additive Sculpture Techniques on a Wheel Thrown Cup

finished vessel with additive sculpture

Subtractive and additive sculpture techniques are great ways to create depth in ceramic surfaces. As the names imply, additive sculpture techniques involve adding material to a surface and subtractive techniques involve the opposite.

Heesoo Lee uses the additive process of sculpture to turn her ceramic cups into ethereal landscapes that I wish I could walk around in. In today’s post, an excerpt from the January/February 2018 issue of Pottery Making Illustrated, Heesoo shares how she builds up her surfaces. Enjoy! – Jennifer Poellot Harnetty, editor.

PS. Check out the full issue to see how she adds color with underglazes.


Using Additive Sculpture Techniques on a Functional Vessel

Building Up the Surface

After placing the vessel on a heavy-duty banding wheel, I begin building up the surface of the cup with coils formed into mini tree-trunk shapes. After rolling the coils out with fresh clay, I use a rolling pin and pony roller to flatten them (1) and then use a sharp knife to cut them into different lengths and widths (2). Since these are landscapes, I think about depth of field and perspective when applying the coils to the exterior and interior surfaces. I begin with the nearest trees, which are the largest coils. Without adding slip or scoring, I apply the coil (3) and dip my finger in water and run it along the length of the coil to press it on.

1 After throwing the cup form, roll out a thin slab for the surface decoration.

2 Cut the slab into thin coil-like strips to form tree trunks.

3 If the cup is freshly thrown, attach the strips to it without slipping and scoring.

I continue to fill in the area with additional tree trunk coils, making them progressively smaller as they become more visually distant, then repeat the process on the interior of the vessel.

Once the tree trunks have been applied, I begin adding knots to the closest trees (4), defining their edges with a rib, then adding scored lines to the background to increase the visual depth (5) and adding horizontal lines to the tree trunk to mimic the bark of an aspen tree (6). Next, I add smaller branches, and then the leaves in the form of small dots. This stage must be done quickly, as the drier the clay becomes the less likely the dots will stay adhered to the surface after the bisque firing. The process is similar to adding coils to a pot to build height. I’m a lefty, so I hold a small pinch of clay in my right hand and tear a small amount off with my left hand and with two fingers, roll the clay into a small dot. I apply it directly to the surface of the pot, without slipping or scoring, and start on the next dot, which I connect to the first dot. I apply dots one at a time, and move in one direction, adding dots and building up the surface (7). I add dots to both the inside and outside of the form. When adding them to extend the rim height, I attach dots to both the inside and outside and pinch the two together to build structure and strength and continue to layer the dots while moving the vessel counter-clockwise, to build the rim to an even height (8). There’s no limit to the height of the rim or number of leaves added, it just depends on the composition and balance of the piece. I check throughout the building process to make sure the edges of the rim are even.

4 Add smaller strips to the trunks to create knots on the foreground trees.

5 Define the trees’ edges with a rib, then add scored background lines for depth.

6 Add horizontal lines to mimic aspen tree bark using small metal tools.

Detail Work with Sgraffito

Once the vessel is leather hard, I begin adding raised detail on the leaves, tree trunks, branches, and background. I add a few clay dots to imitate small leaves and apply them with a tiny dab of water on my finger. I add more incised lines and added clay details to the smaller tree branches and to the eyes, which are characteristic of Aspen trees. At this stage, any more than a small drop of water will change the shape of the vessel. Too much water on the dots, even a fine mist, could result in the collapse of the rim.

I finish off my detail work with carved lines, accomplished with the sharp end of a metal paisley-shaped rib (9). I then take a damp sponge and smooth out the top of the rim to remove bubbles and sharp edges.

When the rim is completely dry, I flip it over onto a foam base and clean up the bottom of the vessel. With the meaty part of my hand, I tap the base of the form to curve the bottom so it sits better after firing. I take a damp sponge and wipe around the base. I don’t do much else to the vessel to avoid obscuring the details I’ve added.

7 Add small, overlapping balls of clay to the surface and rim to represent leaves.

8 Add dots to the inside and outside of the cup, working counter clockwise.

9 Add stem details to the leaves using a paisley-shaped metal rib.

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