Lee Love on tue 2 nov 04
>Dry to powder form. this way you can weigh it and add your percentages of
>oxides. he then said the oxides are still heavier and will sink to the
>bottom so it is best to ball mill the sig/and oxides for two hours so that
>the oxide particle size is similiar to the sig.
I've used Sig at high temp and I don't think the milling
is necessary. At high temps, you loose the "shine" qualities that
occurs with fine particles and burnishing that you get at low temps.
Mat Metz adds his colorants after mixing up the
Sig base, so I don't think there is problems with the oxide settling
out. He uses his sig in vapor firing, often black slip on white
clay, with scrafitto decoration. He did a workshop at NCC back in
'92. I looked in all my notebooks, and couldn't find his recipe.
I looked one more time, and found a folded paper in the pocket of one of
the notebooks. The note was dated 2-2-92 and is written in Mat's
longhand, including his sig_nature.
Here you go:
You add colorants to the base as you please
Terra Sigilata -- Mat Metz
Mix together first:
28 Cups water
40 Grams Calgon (old style)
Then mix in clay:
4000 grams Grolleg.
Lee in Mashiko, Japan http://mashiko.org
http://www.livejournal.com/users/togeika/ WEB LOG
Donald Burroughs on wed 3 nov 04
I disagree that you lose the sheen in the sig at higher temps than
traditionally recommend for it. In fact I investigated coloured sigs while
an undergrad thesis student and found they work just fine at cone three.
They even get more exciting when you apply translucent lustres and refire
at their lower specfied temperatures.
PS try the sludge at higher temps like cone six.
Vince Pitelka on wed 3 nov 04
>I disagree that you lose the sheen in the sig at higher temps than
> traditionally recommend for it. In fact I investigated coloured sigs while
> an undergrad thesis student and found they work just fine at cone three.
> They even get more exciting when you apply translucent lustres and refire
> at their lower specfied temperatures.
This may be a question of terminology. In my opinion, there is a tremendous
difference between sheen and shine. I am completely in favor of
unconventional use of terra sigs, and they can produce a very nice lustrous
sheen at higher temperatures, but the kind of glassy shine you get at
lowfire is not possible at higher temperature. Once you get above low-fire,
the clay starts to shrink, and the polished surface necessarily will start
to crinkle on a microscopic level, reducing the shine.
Best wishes -
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111