Carole Fox on mon 13 oct 03
Oh gosh....I've noticed that some of my horsehair pots have some fine =
cracks in the surface of the terra sigillata - in a random crackle =
pattern - and now I'm totally in a panic that other pieces I've sold =
have this defect as well. What could cause it? And, I'm afraid to ask. =
but- will it cause the terra sigillata to eventually come off?
I've got a sick feeling about this.
Carole Fox in Elkton, MD
- off to teach the homeschoolers- who have a totally different sense =
of time than other children. They can spend an entire class happily =
glazing one small pot!=20
thesilverfox@dol.net
Snail Scott on mon 13 oct 03
At 08:28 AM 10/13/03 -0400, you wrote:
>Oh gosh....I've noticed that some of my horsehair pots have some fine
cracks in the surface of the terra sigillata
The terra sig surface is very brittle and hard, compared
with the clay underneath. Just as earthenware under glaze
can expand with moisture and cause crazing, so can earthenware
under terra sigillata. If the clay underneath was very smooth
when the terra sig was applied, it can flake off with rough
handling, more easily if it's a bit crazed. I will probably
be fine, though. To ease your mind, abuse one of the suspect
pots in the name of science. Dampen the piece and see if the
problem is exacerbated. Rub the surface roughly with your
hand and see if it wants to flake off. Put price stickers
on and pull them off again. If no significant problems are
exposed this way, then sell with confidence. If the buyer
doesn't mind the crazing, then smile and cash their check!
-Snail
william schran on mon 13 oct 03
Carole wrote >some of my horsehair pots have some fine cracks in the
surface of the terra sigillata<
I have found just about all of my raku fired horsehair pots decorated
with terra sig come out of the firing with a crackle pattern,
especially if I've sprayed them with iron chloride. I would imagine
it's the rapid expansion/contraction that's causing it. Have never
had the terra sig. peel off.
Bill
Susan Setley on mon 13 oct 03
In a message dated 10/13/03 6:14:00 PM, snail@MINDSPRING.COM writes:
<< At 08:28 AM 10/13/03 -0400, you wrote:
>Oh gosh....I've noticed that some of my horsehair pots have some fine
cracks in the surface of the terra sigillata
The terra sig surface is very brittle and hard, compared
with the clay underneath. Just as earthenware under glaze
can expand with moisture and cause crazing, so can earthenware
under terra sigillata. If the clay underneath was very smooth
when the terra sig was applied, it can flake off with rough
handling, more easily if it's a bit crazed. I will probably
be fine, though. To ease your mind, abuse one of the suspect
pots in the name of science. Dampen the piece and see if the
problem is exacerbated. Rub the surface roughly with your
hand and see if it wants to flake off. Put price stickers
on and pull them off again. If no significant problems are
exposed this way, then sell with confidence. If the buyer
doesn't mind the crazing, then smile and cash their check!
-Snail >>
Would waxing the surface protect it, or is that not possible? That's what I
have heard is the thing to do with my terra sigged pots after I horsehair
them...
Russel Fouts on tue 14 oct 03
Carole
>> Oh gosh....I've noticed that some of my horsehair pots have some fine
cracks in the surface of the terra sigillata - in a random crackle pattern <<
Are the crackles curling up on the edges? or do they lay flat? Where do the
crackles appear, in the bisque? If they lay flat and show up in the bisque,
you may have stumbled upon one of the secrets of the Terra-Sig Crackle, a
la Pierre Bayle, Tjok Desauvage, Giovanni Cimatti and others.
If you smoke the pieces and then use a liquid wax or oil to finish the
pots, these crackles will absorb more of the oil and will show as fine dark
lines. Can be very beautiful.
Russel
Russel Fouts
Mes Potes & Mes Pots
Brussels, Belgium
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Carole Fox on tue 14 oct 03
Russell wrote:
cracks in the surface of the terra sigillata - in a random crackle pattern
<<
>
> Are the crackles curling up on the edges? or do they lay flat? Where do
the
> crackles appear, in the bisque?
Hi Russell-
The cracks are very fine and by the naked eye, the edges do not appear to be
curling up. I did not notice them in the bisque, but I didn't really inspect
the pots at that point. I actually do find a charm in it on the saggar fired
pots that have been made with the same clay and terra sigillata. But I would
prefer the background for my horsehair pots to be without it.
I hope that my customers don't find it too undesirable!
Carole Fox
Elkton, MD
thesilverfox@dol.net
Alisa Clausen on tue 14 oct 03
Dear Carole,
I terra sigged a white midrange stoneware with red clay that is a local
backyard clay. I bisqued them to cone 06 and then rakued them with
horsehair. In some of the pots, there was a crackle pattern in portions of
the sides,and in some of the pots, where the terrasig was thicker, around
the rim, there are small chips. The chipped areas, very, very small, reveal
a naked raku pattern. I have scratched in the pots and tried to reveal more
of this naked raku pattern, without success. The terrasig is very well
adhered. I was happy that the terra sig stayed, but still unhappy that I
cannot the naked raku thing going. I used beewax to polish the pots and
recommended to those who bought them to do so, every couple of months or so.
Not to rub too vigoriously, as the pots are not that robust compared to
higher fired pots.
So, that may be a comfort to you. Like Snail suggests, try to pick the
terra sig off. You will probably be happy to find that you cannot or that
it will take determination to do so.
Best regards from Alisa in Denmark
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