terra sigillata

updated tue 21 dec 10

sydney doll on fri 20 dec 96

I use Gordon Hutchens' recipe for terra sigillata on my stuff to
raku... when I'm too lazy to burnish the entire piece.
OM #4 Ball Clay 10.5 lbs
Water 3.0 gallons
Lye 48.0 grams

QUESTION: I fire raku to about 06. Can I also use it for cone 6 or
must I have a new recipe? My purpose is to cover the brown long
beach clay that I like to throw with. Haven't found a white clay of my
choice.

Thanks to all of you. I just love this ClayArt.

Sydney and Rob
sydrob@koan.com

YiLi Lin on sat 21 dec 96

Can someone please explain the difference between:
slip
engobe
terra sigillata?

Thanks.

YiLi Lin

Jerry Bennett on sun 22 dec 96

YiLi Lin wrote:
>
> ----------------------------Original message----------------------------
> Can someone please explain the difference between:
> slip
> engobe
> terra sigillata?
>
> Thanks.
>
> YiLi LinHellow Yili: I had to think about your question. But, as I understan
it, slip is a suspension of clay (minerals) in water. An englobe is a
clay and water mixture used to color or decorate a clay body. In other
words, an engobe is a slip. Terra Sigillata is a bit of a different
thing. Terra sigs are a slip, but they are made in such a way as to
select the same size particles of clay. This is done by putting the clay
in water with soda ash or soda silicate. This allows the particles of
clay to fall to the bottom of the container in order of their size. You
decant the smaller and lighter particles and use it as a slip. When
burnished they form a dense, shiny surface, on the ware. They may be
colored with stains or oxides to form colors. In other words, terra
sigillatas are both a slip and an engobe.
YiLi you might want to try this terra sig: Take 800g of water (hot), add
two drops of sodium silicate (it comes as a liquid and is very cheap to
buy- try a ceramic supply store)then add 200g. or Red Art clay. mix it
well and let it settle for a day. Take off the water on top, keep the
middle layer and discard the sticky stuff at the botton of the container.
Try working with a test tile. Paint a thin layer on leather hard clay.
Burnish with the tip of you finger. Put the tile in a bisque firing.
The result is a shiny surface. Most Terra sigs are fired at 06. You can
also make terra sigs with most clays for different colors. Try adding
stains to a ball clay terra sig and experiment with the colors.
Good luck--have fun.
Jerry Bennett jb2119@erols.com

Carissa Doying Cuny on sat 29 mar 97

Hello,
I have been trying to make a rich, deep black with terra
sigillata. Yes, smoking and raku are effective but I want to use the
black in conjunction with other colors. Any ideas?
Thanks,
Carissa

Darrol F. Shillingburg on sun 30 mar 97

Hi Carissa,

Ball mill black mason stains either before adding to, or along with the terra
sig. Or try both and use the one you prefer. Mason stains have to be more finely
ground (smaller particule size) to get intense colors without disrupting the
plattelte bonding of terra sig. ( a good particule mask, and dust management are
required, particularily if grinding dry materials)

Burnishing the terra sig helps intensify the color also, but makes the surface
glossier depending on how you burnish. A good terra sig can be burnished with a
stone when damp, or with 'small' amount of lard as a lubricant and can be
burnished when bone dry with your finger and some olive oil, or with a
'polished' piece of teflon. I use red rougue and a buffer to remove all micro
groving from the teflon.

Good luck in your search for 'sig on the dark side'

Darrol in Elephant Butte, NM

Vince Pitelka on sun 30 mar 97

> I have been trying to make a rich, deep black with terra
>sigillata. Yes, smoking and raku are effective but I want to use the
>black in conjunction with other colors. Any ideas?

Carissa -
There are several ways you can go about this. If you add a small amount of
strong flux like Gerstley borate to a Redart terra sig, you should be able
to get it to become vitreous at low-fire temperatures without sacrificing
the surface. That way, if you reduce as you approach maturing temperature,
the fluxed Redart terra sig will reduce to black black and will stay black
when the other sigs re-oxidize in cooling.

Another option is to just add 5% (of dry weight) cobalt oxide to a Redart
sig. Or you could add 5-10% Mason 6600 Best Black stain to a Redart sig.

If you want to maintain maximum terra-sig satin finish, any of the above
additives should be combined with the finished sig and ball-milled for 24
hours or so.
- Vince

Vince Pitelka - vpitelka@DeKalb.net
Phone - home 615/597-5376, work 615/597-6801
Appalachian Center for Crafts
1560 Craft Center Drive, Smithville TN 37166

Peggy Heer on mon 31 mar 97

Hi...I would just like to add the following to the great advise below.
Use a 'cobalt free' Mason stain and it gives you the same nice balck
without the expense of the cobalt ingredient.
As Always in Clay and wishing I was REALLY into my clay. Another 20 days
and counting. Peggy
----------------------------

>----------------------------Original message----------------------------
>Hi Carissa,
>
>Ball mill black mason stains either before adding to, or along with the terra
>sig. Or try both and use the one you prefer. Mason stains have to be more
>finely
>ground (smaller particule size) to get intense colors without disrupting the
>plattelte bonding of terra sig. ( a good particule mask, and dust
>management are
>required, particularily if grinding dry materials)
>
>Burnishing the terra sig helps intensify the color also, but makes the surface
>glossier depending on how you burnish. A good terra sig can be burnished with a
>stone when damp, or with 'small' amount of lard as a lubricant and can be
>burnished when bone dry with your finger and some olive oil, or with a
>'polished' piece of teflon. I use red rougue and a buffer to remove all micro
>groving from the teflon.
>
>Good luck in your search for 'sig on the dark side'
>
>Darrol in Elephant Butte, NM

Peggy Heer / Heer Pottery E-Mail p4337@connect.ab.ca
Edmonton AB, Canada
http://www.ffa.ucalgary.ca/artists/pheer/

katie rose on sun 26 oct 97

hi clayarters,

i know the topic of terra sigillata has been discussed extensively on this
list, and up until now i have paid no attention in it...so, of course, that
is what i am needing to know about now.

if you knowledgeable folk could send me any info on procedure, application
etc of terra sig, it would be grately appreciated--the simpler, the better.

thanks for all help.

katie rose

****************************************************
katie rose
raven@sedona.net

"Love is the reflection of God's unity in the world of duality. It
constitutes the entire significance of creation." (Meher Baba)

Neil Berkowitz on mon 27 oct 97

katie rose,

http://www.dejanew.com is a good source for archives of posting. A
search of "terra sigillata" had four posts (2 from Clayart) from their
current database and 59 from the older database. A "terra sig*" search
is likely to come up with more.

--
><><><><><><><><><><><><><><><><><><><><><><><><><><><><><
Neil Berkowitz
neilmber@ix.netcom.com
http://www.netcom.com/~neilmber/

Owen Rye on mon 27 oct 97

> ----------------------------Original message----------------------------
> hi clayarters,
>
> i know the topic of terra sigillata has been discussed extensively on this
> list, and up until now i have paid no attention in it...so, of course, that
> is what i am needing to know about now.
>
> if you knowledgeable folk could send me any info on procedure, application
> etc of terra sig, it would be grately appreciated--the simpler, the better.

Had this theory years ago that perhaps the ancient Greek potters did
not work to the sigillata formula developed by an analytical chemist
this century in an attempt to replicate the old sigillatas. Instead
of all the processes of mixing, adding chemicals, waiting patiently,
fractionating and so on - what if - what if they went to a dry lake
bed, collected up that shiny layer that forms on top of the claypan,
stirred it up in water, and applied it - would that work?
Only one way to find out - do it. Luckily I had the idea in the
middle of a drought. Drove out in the middle of a five mile long lake
(getting bogged in the process........interesting!) collected the
stuff, stirred it up in water with a paint stirrer, applied a watery
mix to bisque, fired it - worked fine apart from some 'crazing'.
Problem solved by applying it to leather hard ware.
My guess is a large area, shallow lake would provide the finest
sediment; and obviously you will rarely find such a dry lake; if it
is in a desert area soluble salts may be a problem. Adding about a
half percent of barium sulphate (yes, sulphate, not carbonate - it is
non toxic, used in medicine for stomach x-rays, and was used in
England in the past for salty brick clays) should neutralise the
soluble salts.
I like natural approaches; not a chemophobe, just like being a child
of nature...
Owen Rye.....going into summer in Australia.....brings out some of
the world's most venomous snakes in my place, which tempers the
exploring of nature somewhat.....at least you have 15 minutes to jot
down any last thoughts..
Owen.Rye@Arts.Monash.Edu.Au

Vince Pitelka on mon 27 oct 97

>i know the topic of terra sigillata has been discussed extensively on this
>list, and up until now i have paid no attention in it...so, of course, that
>is what i am needing to know about now.
>if you knowledgeable folk could send me any info on procedure, application
>etc of terra sig, it would be grately appreciated--the simpler, the better.

Katie -
You can find my spiel on terra sig in the archives, plus Tony Hansen has it
on the IMC webpage at:
http://digitalfire.com/education/glaze/terasig.htm
- Vince

Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166

judy motzkin on tue 3 feb 98

In the late 70's, I started trying to find and figure out all I could
about terra sig. At that time the best info I found was in a
wonderful book called Ceramic Science for the Potter, by
Lawrence,published by Chilton. In 82 I started seriously using ts in
my work as I still do. When in the NCECA newsletter Winter 83 came
with an article about terra sig by Val Cushing with all the info I had
also gound, I only wished that it had come earlier. That article was
also printed in Studio Potter, I think it was in 84. These two pieces
are the best I have seen to date on the subject. I must also say
however that terra sigillata is the simplest, least mysterious,
inexpensive of materials and what is to be gained from experience
cannot be read or researched. But that is true of most things.
jem




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TETKOWSKI@aol.com on sat 9 jan 99

TERRA SIGILLATA & Calvert Clay
I've been using Calvert Clay as my basic red terra sig for 20 years and have
finally run out of my personal supply though the mine has been closed for
years.
* If anyone has Calvert, please contact me.
* Or if you would suggest your favorite clay for red terra sig.
Thanks
Neil
212/255-1850
tetkowski@aol.com

Louis Katz on sun 10 jan 99

Hi Neil,
My wife has had some near Calvert like tests of Sig with blends of Redart and
KT1-4 Ball clay.
Louis

TETKOWSKI@aol.com wrote:

> ----------------------------Original message----------------------------
> TERRA SIGILLATA & Calvert Clay
> I've been using Calvert Clay as my basic red terra sig for 20 years and have
> finally run out of my personal supply though the mine has been closed for
> years.
> * If anyone has Calvert, please contact me.
> * Or if you would suggest your favorite clay for red terra sig.
> Thanks
> Neil
> 212/255-1850
> tetkowski@aol.com

--
Louis Katz
lkatz@falcon.tamucc.edu
NCECA Director At Large
Texas A&M-CC Division of Visual and Performing Arts Webmaster (512) 994-5987

Troy Setiawan on sun 10 jan 99

Dear Neil,
I've tried terra sigillata, burnished w/ a pebble until smooth and shiny, but
when it came out from the kiln cone 06, it look dull and awful. Any
suggestions?
Maureen


TETKOWSKI@aol.com wrote:

> ----------------------------Original message----------------------------
> TERRA SIGILLATA & Calvert Clay
> I've been using Calvert Clay as my basic red terra sig for 20 years and have
> finally run out of my personal supply though the mine has been closed for
> years.
> * If anyone has Calvert, please contact me.
> * Or if you would suggest your favorite clay for red terra sig.
> Thanks
> Neil
> 212/255-1850
> tetkowski@aol.com

John Guerin on tue 12 jan 99

In a message dated 1/10/99 5:18:10 AM PST, mohan26@earthlink.net writes:

<< I've tried terra sigillata, burnished w/ a pebble until smooth and shiny,
but
when it came out from the kiln cone 06, it look dull and awful. Any
suggestions?
Maureen >>

Hi Maureen,

Clay is composed of microscopic platelets of material which end up arranged at
rather random angles to each other. When you burnish the surface of a pot,
you compress the clay and force the microscopic platelets to arrange
themselves parallel to each other to form a reflective surface which gives you
the "shiny finish". However, when the pot is fired these microscopic
platelets buckle when the clay vitrifies and a lot of the "shine" disappears.
When I was studying with a Hopi Potter, he showed me an old Indian trick to
restore the shine. After the pot is fired, apply a coat of floor wax and buff
it with a soft cloth after it dries. The burnishing process not only forces
the platelets to line up on the surface, but it also compresses the clay and
closes up the pores so that it will support a coating of the wax which is
actually a plastic acrylic coating. A non burnished surface will just absorb
the acrylic coating, but the burnished surface will support the acrylic
surface and shine up very well. If you want an even harder finish, JASCO TILE
SEALER does an even better job.

John Guerin
Tucson, AZ

terryh on tue 12 jan 99

------------------
Maureen:
O6 is too high. bisque-fire at O9 or lower. and of course,
raku/pit fire at similarly lower temperature. otherwise,
sheen will disappear.

Neil:
for red terra sig, i use OM4 ball clay, mixed w/ red iron oxide.
or w/ mason stain. similarly, i add cromium oxide for green
terra sig. cobalt oxide for blue. etc. etc.

good luck
terry
terry hagiwara
e-mail: thagiwara=40halnet.com (W)=3B terryh=40pdq.net (H)
web: http://www.geocities.com/SoHo/Cafe/3755

----------------------------Original message----------------------------
Dear Neil,
I've tried terra sigillata, burnished w/ a pebble until smooth and shiny, =
but
when it came out from the kiln cone 06, it look dull and awful. Any
suggestions?
Maureen


TETKOWSKI=40aol.com wrote:

=3E ----------------------------Original message----------------------------
=3E TERRA SIGILLATA =26 Calvert Clay
=3E I've been using Calvert Clay as my basic red terra sig for 20 years and =
have
=3E finally run out of my personal supply though the mine has been closed =
for
=3E years.
=3E =2A If anyone has Calvert, please contact me.
=3E =2A Or if you would suggest your favorite clay for red terra sig.
=3E Thanks
=3E Neil
=3E 212/255-1850
=3E tetkowski=40aol.com

Vince Pitelka on tue 12 jan 99

>I've tried terra sigillata, burnished w/ a pebble until smooth and shiny, but
>when it came out from the kiln cone 06, it look dull and awful. Any
>suggestions?

Maureen -
A polished terra sig finish (polished with a soft cloth or brush, or with a
piece of grocery-store bag plastic) can be fired to cone 06 without loosing
its shine, but a burnished finish cannot. When you burnish with a stone or
any other hard, smooth object, the clay is compressed to an extreme degree,
and has no capacity for shrinkage at all. You can fire as high as cone 010
or so without damaging the burnish. Any higher than that, and you begin to
get a little shrinkage, and the burnished surface crinkles up on a
microscopic level, leaving a matte surface.
- Vince

Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166

Richard Ramirez on wed 13 jan 99

Maureen,
Sometimes the hardest things to accomplish or acquire and can be the most
delicate and fragile.....try a very low bisque... to be porus.. then drown it
in a bucket of smoldering sawdust...after, see the carbon shine!!!...seeing
this will guide your pebble, the next time you take the journey...
again...again..and a...

"The Clay Stalker" Richard Ramirez

Anji Henderson on sun 1 aug 99

Would have posted directly, but I guess I was to lazy to find the original
message.. Also, someone else may be interested in clipping.. I am also
assuming that yall' know how to make it. If not there were postings from
Vince a few months ago, maybe Nov or Dec..

To the one who questioned -- The white here is well, a more specific recipe
than the one I sent to you..
ALL IN GRAMS

White Terra
Kentucky Ball Clay(om4) 200
Water 800
1000
Add Calgon 10

Orange
Cedar Heights Red Art 200
Water 800
Add Calgon 10

Red
Kentucky Ball Clay(om4) 50
Water 400
450
Add Red Iron Oxide 50
Calgon 10

Maroon
Kentucky Ball Clay(om4) 180
Water 800
980
Add
Manganese Dioxide 5
Red Iron Oxide 50
Calgon 10

Hi Ho, Hi Ho, it's off to glaze I go....
Anji

I.Lewis on wed 8 sep 99

------------------
There is an interesting illustrated article in Tile and Brick International,
August 4/99 volume 15: p253-56 under the title =22Terra Sigillata: A =
Sintered Slip
in Use since Antiquity=22 by S. =C7izer and others of D.E.=DC G=FCzel and =
Sons, Izmir,
Turkey.

Information is given about the historical nature of this ceramic surface =
finish,
of the preparation of antique slip and the ancient firing process. The =
authors
then describe the preparation of slips, provide a series of recipes then
describe their experimental firing programme.Illustrations show the effect =
on
red and white clay bodies.

I found it interesting that early Greek potters introduced water into the =
kiln
as a reducing agent when they fired Red and Black ware. The authors did not
explain why they substituted organic matter in preference to water.

Subscribers wanting more information should contact the Editors, Tile and =
Brick
International at Verlag Schmid GMBH, PO Box 6609, D-79042, Freiburg, =
Germany,
view http://www.ceramic-journals.com or e-mail =
ceramic=40ceramic-journals.com

I am sure many of you who are interested in this process, as indicated by =
recent
postings, would find this short technical discussion very interesting

Regards to All

Ivor Lewis. In South Oz where we still need rain to finish the season.

BobWicks@AOL.COM on sun 29 sep 02

Judy:
I am using my own Terra Sigillata and it's not as labor intensive as you
indicate. I am using Standard's low fire Red clay for color. I use one part
of dry Red clay to 4 parts water and a small amount of Darvon defloc and mix
with a cocktail mixer. I allow this to stand for 20 minutes and pour off
everything but the muddy sediment. I repeat this about 4 to 6 times, but I
do other things while the mixture settles. Believe me it is well worth the
effort and the results are outstanding. The finish is so fine it can be
polished with your finger or a Kleenex or if you want a higher gloss you can
use a burnishing spoon. Fire well below cone 04.

Good luck;
Bob.

Judith S. Labovitz on sun 29 sep 02

I kinda looking for a shortcut (I know...not always a good idea...) for
terra sigillata, and I was wondering if any of you had used the
commercially prepared stuff sold by "clayart center"


I really like the effect, but it is not something I will be doing with any
degree of regularity; the methods of mixing my own (found in the
archives) seem too labor intensive for the limited amount of use....

any advice??

thanks

judy (lansing area Michigan)

Russel Fouts on mon 30 sep 02

Judith


>> I kinda looking for a shortcut (I know...not always a good idea...) for terra sigillata, and I was wondering if any of you had used the commercially prepared stuff sold by "clayart center" I really like the effect, but it is not something I will be doing with any degree of regularity; the methods of mixing my own (found in the archives) seem too labor intensive for the limited amount of use.... <<

I don't like anything to be too much work. Go to

http://www.mypots.com/resource.htm

And look at my Terra-Sig Primer.txt

Not labor intensive at all. You can even scale the method down to using
a blender.

Good luck

Russel (Lazy Ex Michigander)

-----------------------------
--

Russel Fouts
Mes Potes & Mes Pots
Brussels, Belgium
Tel: +32 2 223 02 75
Mobile: +32 476 55 38 75
Http://www.mypots.com
http://www.Japan-Net.ne.jp/~iwcat

"There is a theory which states that
if ever anyone discovers exactly what
the universe is for and why it's here,
it will instantly disappear and be
replaced by something even more bizzarly
inexplicable."

"There is another theory which states
that this has already happened!"

Douglas Adams' The Hitch Hiker's Guide to the Galaxy

Bobbruch1@AOL.COM on mon 30 sep 02

I think that you can keep terra sigillata for quite awhile, which makes the
effort worthwhile even if you are only going to use it every so often.

Bob Bruch

<<<<
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<<terra <<commercially <<effect, but it is not <<regularity; the methods of mixing <<too labor intensive for the limited amount <<