Sculpting the Bas Relief Tutorial part 1

This tutorial is one way to sculpt the bas relief. I have already sculpted two bas reliefs in a series depicting strong young women and this is the third in that series.

I am sculpting in water-based clay. Can you sculpt in oil based or other clays? Absolutely and sometimes I use oil-based clay. But as this sculpture is 18" x 24" that equals to about 40 pounds of clay. If I were using oil-based clay, that would be about $150-$200 in oil clay and a lot of time softening the clay in a clay-warmer as oil-based clay can be quite hard, especially in cooler climates like Colorado.

A benefit with oil-based clay is that I would have minimal board prep. Oil-clays are quite sticky and would adhere to a slick board or Plexiglas's with the need to prepare the board - just apply the clay and it will hold in place.

But I have chosen water-based clay for the texture and surface qualities. In theory, I could sculpt this, hollow out the back a bit and fire, however it's quite large, which would require a very large kiln and flat pieces like reliefs are susceptible to warping when drying.

Instead of firing this as a single piece, I will be sculpting in clay, making a mold and casting in a permanent medium - in this case either bronze (which would be quite heavy at this size) or a polymer modified fiberglass-reinforced gypsum (brand names Forton and Aqua-Resin).

A) The first step is designing the art. Here I have the sketch at full size of 18" x 24" of the new piece "Setting Her Sights".

B) Next I cut out the image

C) I have a piece of wood cut larger than the overall size of the sculpture and has a grid made from small screws and picture wire. This is going to anchor the clay onto the board so it doesn't move or slip around. You'll see that I've sealed off the board using packaging tape - that will keep it from leaching the water out of the clay. It will also help later in mold making.

D) here you can see that the screws and wire are rusted from contact with water-based clay from my last relief. That's not a problem as the clay isn't the final piece - the casting made from the mold is. But you could also use galvanized metals to avoid the rust issue.

E) Now I start slicing off tiles of clay about 1/2" thick and slap them down onto the board. You want to slap them because you want good contact without air pockets.

F) Layer the tiles across the entire grid on the board

G) Taking a block of wood or a rolling pin pound down the clay.

H) Roll or pound until flat

I) Finally I take a serrated metal kidney tool and crosshatch the clay to make a seamless surface. The clay is now one flat seamless tile measuring about 19" x 12" x 1/2" deep and is ready to begin the process of sculpting a bas relief.