I am drawn to the naked pot. Just as a woman’s silk slip emphasizes every curve and crevice of her body, terra sigillata shows off the nuances of the clay surface. Its reflective satin sheen contrasts with the light absorbing, matte surface of the bare clay. It is the play between shine and matte, texture and smooth, interior and exterior, that interests me. To achieve a refined smooth surface on my coil, slab, and pinch pots, I follow a number of steps: At leather hard, I scrape the raised areas with a fettling knife to lessen the amount of sanding. At bone dry, I sand the surface (wearing a respirator) with successively finer grit re-usable sand sponges. Using a cloth rag, I wipe off the excess clay dust, so that the course particles of clay will not “contaminate” the terra sigilatta. I layer 3 to 5 coats of terra sigilatta (the consistency of milk) onto the surface using a soft brush. When the surface is no longer wet, but remains moist, I polish the terra sigillata using a porous plastic bag wrapped tightly around my finger or a small sponge. Every minute mark shows -- the brush strokes, a tiny drip, a scratch in the clay surface -- and that is the beauty of it. I use white earthenware that I bisque at cone 09, and smoke fire in hard wood shavings.
14 cups water 1170 g. EPK or Avery(kaolin) 270g. ball clay 60 g. bentonite (mix bentonite into other dry ingredients before adding to water.) 7.5 g calgon (must be old formulas of calgon) [Otherwise try using 8g Soda Ash]
1. Add calgon to water 2. Mix clay in and let mixture settle, undisturbed for 20-24 hours 3. Siphon top two layers off. The top two layers are your terra sig.