Suzana Lisanti on sun 24 dec 00
How did the Greeks get terra sig to be waterproof? They used it on vessels
used to serve wine and water...
-Suzana Lisanti
Cambridge, MA
Cindy Strnad on sun 24 dec 00
Hi, Suzana.
You know, I'm not sure about the Greeks--there are plenty of people on this
list who can help you with them, and probably will--but the SW Native
Americans used burnishing and terra sig to decrease the permeability of
their fired vessels. If you compare a terra sig piece with a similarly fired
plain or even burnished piece, you'll be able to actually see the difference
in reaction to liquids. Sprinkle with a few drops of water and watch the
results.
It's not so much that terra sig can make a vessel impermeable to liquids,
but that in makes a vessel less permeable. Like the difference between a
paper towel and a piece of high quality slick paper. You have to do the best
you can with what you've got. Good terra sig is actually quite good, I
think.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
http://www.earthenvesselssd.com
vince pitelka on sun 24 dec 00
> How did the Greeks get terra sig to be waterproof? They used it on
vessels
> used to serve wine and water...
Suzana -
There are degrees of waterproof. A pot lined with terra sig will be
relatively waterproof, and whatever wine or oil seeps through will probably
dry in the pores and complete the waterproofing process. Some liquid or
food is going to impact the clay on these wares, and bacteria and
microorganisms are bound to grow in the clay, and will invariably get into
the food. The critical matter here, as is true with bonfired tribal pots,
is that the people in this culture grew up from birth eating foods stored
or prepared in these pots, and the bacteria and microorganisms growing in
the clay became a natural part of their intestinal fauna. We, on the other
hand, have no resistance to those bacteria and microorganisms, and could
likely get food poisoning.
Best wishes -
- Vince
Vince Pitelka
Home - vpitelka@dekalb.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
http://www.craftcenter.tntech.edu/
Khaimraj Seepersad on sun 24 dec 00
Season's Greetings to All ,
Susan ,
your looking at two different situations here -
[ 1 ]
Burnished ware - finely levigated clay slip , polished by hand .
As done by the Moche' or other Amerindians .
[ 2 ]
Attic Ware - finely levigated clay slip , made vitreous through
oxidation to 800 deg.c , next reduction at 950
deg.c , then re-oxidising the body at 900 deg.c . Using black
iron oxide as a flux . This slip made into glass , will turn a razor
blade .
To read more about firing Attic Ware see -
Greek Vases by Dyfri Williams .
There is also a variant called red gloss ware .
The Mayans had just about discovered this technique of Attic
Ware , and the effect will occur on some slips with Amerindian
wares when using a sugar based slip .
Hope this helps ,
Khaimraj
-----Original Message-----
From: Suzana Lisanti
To: CLAYART@LSV.CERAMICS.ORG
Date: 24 December 2000 6:04
Subject: How did the Greeks get terra sig to be waterproof?
>How did the Greeks get terra sig to be waterproof? They used it on vessels
>used to serve wine and water...
>
>-Suzana Lisanti
>Cambridge, MA
Gavin Stairs on sun 24 dec 00
At 12:19 PM 12/24/00, Cindy Strnad wrote:
>Hi, Suzana.
>
>You know, I'm not sure about the Greeks--there are plenty of people on this
>list who can help you with them, and probably will--but the SW Native
>Americans used burnishing and terra sig to decrease the permeability of
>their fired vessels. If you compare a terra sig piece with a similarly fired
>plain or even burnished piece, you'll be able to actually see the difference
>in reaction to liquids. Sprinkle with a few drops of water and watch the
>results.
>
>It's not so much that terra sig can make a vessel impermeable to liquids,
>but that in makes a vessel less permeable. Like the difference between a
>paper towel and a piece of high quality slick paper. You have to do the best
>you can with what you've got. Good terra sig is actually quite good, I
>think.
Hi everyone,
A small addition to the above. I have seen Roman tumblers or beakers of
terra sig over terra cotta. A museum curator in a small french town
explained that the name, in Latin, comes from the fact that these pots were
finer than ordinary terra cotta, and they were signed by their makers. So,
pots made of earth (terra) and signed (sigilata).
Anyway, are you familiar with the greek wine called retsina? Retsina means
resin, as from tree sap. Many fermented liquors from the mediterranean
region have some resin in them. In the spirits, like french pastice, it is
the part that turns cloudy white when water is added. Presumptively, this
taste comes from the use of resin sealed, terra cotta urns and amphorae to
store and ferment wine. The greeks having gotten used to the taste, it has
survived to modern times. The resin is soluble in alcohol, so the
distilled spirits can absorb even more than the wine, which is clear. The
addition of water precipitates the resin, which becomes visible as the
milky cloudiness in the mixed drink. I suspect that the flavoring of gin
may have a common origin.
Most cultures that used terra cotta to hold liquids discovered some local
sap or treatment to seal the pores, so that liquids could be held for long
periods without seepage. One such treatment uses milk, or whey. The
Indians of the southwest used a local sap, the name of which I can't
recall. Many trees and herbs have a milky sap containing some kind of
latex which makes a good sealant. I'm no expert at this, but I would
expect that different sealants would be used for holding oils, water and
alcoholic liquids, at least in some cultures, as these liquids are all very
different in their chemistry and interaction with sealants and pores.
Merry Christmas to all, Gavin
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