Techno Tip: Slip-carving & terra sigillata at cone 10 reduction T have dene slip-carving off and on ever since [ started potting, [ love eo warch the patoems emerge from the smooth porcelain surface. Nowadays, potters’ cendonicis in the wrists and hands dictates that J cut down on che amount of chrowing [ can do. About 75% of my potting time is spent decorating by slip-carving. My favourite slip is a black, the recipe originally fro Henry Varnum Poor, Bur since it has passed through many hands, it haa undoubtedly undergone many modificacions. Black Slip: Barnard clay 500 Cobalt Carb, 200 Mang. Diexide 200 Clay 1500) The clay component of this slip is my porcelain clay body. However, when | use this slip on stoneware [ replace half che clay component with ball clay. Any clay can be used in this slip. Bur it is important chat the clay component be very smooth with no grog init. Recencly [ have fer grt Lari the above porcelain alip on earthenware and it works just as well at come O2 as ar cone LO. How abour chac tor a wide-firing range! The slip is applied co che learher hard pot. Two thin coats are booshed on. This black slip dees net need to be particularly thick. When chick, ic tends os crater (which is beautiful, but not great for functional pieces), Then the carving is done in leather hard surface. | have a fairly clear ides of the design before i start. Lf the surface needs to he divided into sections, | do that by eye-balling and marking with pencil lines. Most of the carved lines are drawn free-hand. 1 may use a sttaight-edge (flexible plastic banding cape} for seme long lines thar run the length of the pot, but NEVER all af them. There seeds to be a bit of free- hand wobble just to keep the werk from locking factory made. Adter bisquing, | either use a glaze {turquoise glaze over blue slip or black dip, white glaze over blue or gray slip, etc.) or my signature Page 7 technique of a ned clay terra sigiata over the black slip. Ag cone lO the black slip becomes vitreous enovgh to incorporate the terra sigillata and hence shows through as black. This is nor true at che usual terra sigillata earthenware firing temperature, Since terra sigillata loses its sheen when high-fired, | don't bother oo buff ic, and [ Put it on after the pots are bisqued when they are easier to handle, [tis difficulr to get terra sigillaca on evenly and any variation (drips and overlaps} tends to shiny up mone at the high-fire temperatures. [ spray any pieces char are t00 large for dipping Tetra Sigillara Recipe: 4000 Elms. Newman Red Clay 10 litres warer 40 pms. lye Mix thoroughly and let stand for 48 hours. Then decane to 3/4 for weable terra sigillara, Judy Weeden Aftosa Amaco Axner Bailey Brent Cone Art Kilns imco Clay Kemper Tools Laguna North Star Orton Cones Seattle Clays Shimpo Pacifica Wheels Soldner Mixers Venco Pugmills You work in clay... We have what you need Clay, Raw Materials, Glazes, Tools, Equioment | 2071S. Wellington Rd. RR#4_ Nanaimo,BC V9RSX9 PH.250-716-9966 On the service road next to the Trans Caneda Highway - South end Nanaime and our PRICES are FANTASTIC thee POTTERY Warehouse Now open on Vancouver Island