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Ever since discovering 'sig' through my classes with Sandi Pierantozzi (initially) and Jimmy Clark, I have been collecting and testing different terra sigillata recipes and their firing range. 90% of my clay beads are finished with terra sigillata and fired anywhere from cone 4 (electric) to cone 10 (in a gas kiln). The results are earthy and allow the clay beads to remain "open" enough to absorb the essence of the wearer or serve as carriers for essential oils.
This is a short article about how Terra Sigillata is made and my collection of recipes.
Terra Sigillata enhanced stoneware vase fired to cone 6 in an electric kiln.
Making Terra Sigillata
BASIC MIXING INSTRUCTIONSBASIC SIG
200 grams White ball clay such as Tenn 10 or Kyom4
800 grams water (3 ½ Cups)
10 grams Calgone*
Use hot water and add the Calgone* to dissolve. Add the clay, stir thoroughly and allow to ‘sit’ undisturbed for 2 – 7 days in a tall clear glass or clear plastic jar (A large mouth opening is preferable). The mixture will divide into 3 distinct layers. Use a siphon and go down through the top layer of water to the bottom of the middle layer (which is the Terra Sigillata) and siphon it into a clean container. I then keep some of the top layer of water to add to my sig later in case it gets too thick. Dispose of the bottom clay layer in a responsible manner.
If the sig still seems a little thin (it should be the consistency of light cream) allow it to sit uncovered for a week or two and remove some of the top water before stirring to mix to obtain the proper consistency. Add colorants after decanting and ball mill if possible to retard settling.
“AGED” Terra Sigillata is some of the best! – some artists allow all the water to evaporate from the sig and then store it in powder form, adding water back into it as needed.
*CALGONE is sodium hexametaphosphate.
BH BASIC TERRA SIGILLATA RECIPES Cone 04 - 10
BASIC SIG 200 grams White ball clay such as Tenn 10 or Kyom4 800 grams water (3 ½ Cups) 10 grams Calgone* ALBANY SIG 50 grams Albany slip 50 grams KYOM4 400 grams water 10 grams Calgone* RED ART SIG 200 grams Cedar Heights Red Art Clay 800 grams Water (3 ½ Cups) 20 grams Calgone* SALMON SIG 50 grams Red Art 50 grams Ball clay 400 grams water 5 grams Calgone* TEA ROSE SIG (an alternative to Red Art sig) 300 grams Red Art 100 grams KYOM4 7 cups water (1600 grams) 25 grams Calgone* OCHRE SIG by Weiser 1663 grams Cedar Heights Gold Art 66 grams Yellow Ochre Add to a mixture of: 8 grams soda ash 16 grams Calgone* 1 gallon water This sig produces a nice golden peach at cone 06-04 and yields a darker more golden finish when fired to cone 6. It looks very similar to Albany Sig and is a good replacement for it. The Weiser Ochre sig decants much faster than the other sig recipes and its thinner (more translucent) consistency works really well, buffing to a beautiful sheen. It does leave a lot more bottom sludge. I have also allowed it to sit an additional 2 – 3 weeks after the initial siphoning and removed more of the top water layer to thicken up the mix and make it less transparent. Gloria Singer’s BASIC SIG 14 cups hot water 2 tsp Calgone* 8 ½ cups KYOM4 2 cups EPK ¼ cup Bentonite I also like this as a basic sig recipe. I seem to get less color settling with it and have only tested the sig colored with Onyx Mason stain fired up to cone 10. Bernadette Curran’s FAUX SIG 750 grams EPK 1500 grams Ball Clay (OM4, Tenn 10, etc.) 14 cups water 45 grams soda ash Add the soda ash to the water and whisk to blend well. THEN add the EPK and ball clay, whisk to blend then allow to stand for 2 to 3 days. Do not siphon; use the entire mixture. Apply thin on greenware or bisque. This faux sig fires from cone 04 – 6 and can be colored successfully with Mason stains. |
FEDERIGHI Terra Sigillata Recipes Cone 010 – 02 Light Red Terra Sigillata 800 grams hot water 200 grams OM4 ball clay 20 grams Red Iron Oxide 10 grams Calgone* Black Terra Sigillata 800 grams hot water 200 grams Cedar Heights Red Art 10 grams black copper oxide 10 grams Manganese 10 grams Calgone* Note: I prefer to color my sig after I have decanted the clay, Calgone* and water. This can also be colored with Mason 6600 stain instead of the Black copper oxide & manganese. White Terra Sigillata 1000 grams hot water 200 grams OM4 ball clay 75 grams EPK 150 grams Talc 50 grams Zircopax 25 grams Calgone* Michael Wisner’s Painting Sig 1 heaping teaspoon Calgone* 1 gallon water 2 lbs. KYOM 4 ball clay Decant for several days, siphon off middle layer. NOTE: Adding a dash of commercial underglaze to color this sig will make it easier to see when applying to the same color pot but will not affect the final color after firing. Cheryl Tall’s ^010-2 Terra Sig (Modified from Judy Moonelis Recipe) 500 grams OM4 Ball clay 1000 grams Red Art or EPK (to duplicate Judy’s recipe) 14 Cups Water 7.5 grams tri-sodium phosphate For certain colors, Cheryl does the following – OCHRE – To 1 ¼ cups Basic sig, add 3 Tblsp. Rutile & 2 Tblsp. Gerstley. PINK – To 1 ¼ cups Basic sig, add ¼ c. 6020 Mason & 2 Tblsp. Gerstley. Busch White Terra Sigillata 40 grams Borax 200 grams Ferro Frit 3134 1800 grams Cedar Heights Gold Art Add to a mixture of: 20 grams Calgone* 1 gallon water Ball mill for 24 hours then decant. After decanting, colorants may be added. To achieve a smoother finish, ball mill again after adding colorants. Deb LeAir Painting Sig 1/3 cup of terra sigillata base 2 Tblsp stain 1/4 tsp of frit 3134 If using oxide or carbonates, skip the frit altogether. Floche Sig 19% Ball clay 77% China clay 0.5% Bentonite 0.5% Sodium hexametaphosphate (Calgone) |
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