Donna Kat on wed 26 mar 08
On Sat, 22 Mar 2008 14:22:04 -0600, Deborah Thuman
wrote:
>I'll be doing a naked raku next month. I'm sort of on my own with this
>because my teacher isn't fond of raku. Then again, I can experiment
>like crazy because my teacher isn't fond of raku. Anyway, I've been
>told that I have to use a special slip recipe for naked raku and NOT to
>buy the commercial slip glaze. I've looked through the naked raku
>archives, and I found the recipe people suggest. But.... it's in
>percentages and not in grams. How do I convert this recipe?
>
>SLIP (by weight)
>================
>5 % CLAY : Fat French Stoneware "Limoges" clay
>2 % QUARTZ (= flint = siliciumoxide)
>3 % KAOLIN (EPK)
>very important : sifting 4-5 times through fine sieve (80 or 100 mesh)
>consistency : medium to fat milk
>
Given that this has to add up to 100% to make any sense then as stated it
has to be
50% clay (ball clay?)
20% Silica
30% EPK (kaolin)
Now you have to decide how much slip you want. If you want 100 grams of
dry ingredients then you would have
50 grams clay
20 grams silica
30 grams epk
1000 grams of dry ingredients would be
500 grams clay
200 grams silica
300 grams epk
Basically whatever total amount of dry material you want would then be
multiplied by
.5 (for clay)
.2 (for silica)
.3 (for EPK)
I hope that is the question you are asking. Donna
Donna Kat on wed 26 mar 08
http://ceramicartsdaily.staging.10floor.com/feature/featuredetail/2008_03/c
arciaterrasigillata.aspx
or
http://ceramicartsdaily.staging.10floor.com/index.aspx
Meant to give you this as well. Donna
March 26, 2008
Joan Carcia's Terra Sigillata Recipe
by Joan Carcia
On Monday, we brought you Joan Carcia=92s saggar-firing technique. Today, as=
promised, we=92ll share the other secret to her success with this technique:=
her terra sigillata recipe. Enjoy! - Jennifer Harnetty, editor.
This recipe (see ingredients below) makes about 1 cup of white terra
sigillata. Mix it in a 1-gallon container with a lid. Mix the trisodium
phosphate into the water, then add the clay slowly over a period of 15=9620
minutes, letting each addition slake down before adding more. After all
the clay has been added, let it sit for about half an hour, then
vigorously mix with a spatula for about two minutes. Then put the lid on
the jar and shake it vigorously for another two or three minutes. Next,
place it in a spot where it will not get moved for two weeks.
After two weeks, siphon off the clear water on top. Then, using a turkey
baster, siphon the next layer (terra sigillata) and put it into a jar for
using. Throw out the sediment that is left at the bottom. The terra
sigillata should be like skim milk in consistency. If it is too thick, you
can add a little water.
I apply this terra sigillata to bone-dry pots with a soft brush,
overlapping my strokes. I put two or three coats on and burnish the pot
either after each coat or after the final coat with a soft cloth. It is
important to stir the terra sigillata mixture to keep it in suspension
during application. I bisque my pots to Cone 08 before firing in the gas
kiln.
More images of Joan Carcia=92s work can be seen at www.jcarcia.com.
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