Paulette Carr on thu 17 apr 08
Hi, Vince!
Just for my reading pleasure (not to mention, education!), I just re-
read the sections in your book on colored clay: there, you suggest
using a clay body that is not vitreous at low-fire temperature, and
is not a talc body. Is this the clay body that you were using when
you were doing the low-fire work or were you actually using a talc
body? Would you say that the clay body that you were using was at or
near it's maturity when you were working at low-fire temperatures?
It occurred to me that if you are still using those loaves, and you
are now working at ^6, the clay body that you used then may not have
been a talc body (as I assumed), but perhaps the one that you suggest
in your book.
If you were not firing to or near maturation of your clay body, when
firing at low-fire temperatures, then that might explain the
requirements for higher levels of stains to achieve a given
intensity, and would help me to understand what Curt and Bryan wrote
about the increased color intensity and vitrification. But, if you
were using a talc body... well, observations are "golden", especially
if they are reproducible!
I am testing now. Soon I will have some observations to add as well.
Many thanks!
Paulette
Paulette Carr Studio
St. Louis, MO
Member, Potters Council
Vince Pitelka wrote:
"When I started using colored clays I was doing low-fired work
exclusively, and when I wanted deeply saturated colors it took a lot
of stain. It is true that the higher you fire, the less stain you
need to achieve the same level of saturation. In some of the
pictorial inlaid colored clay pieces I did twenty years ago, I wanted
to achieve a pitch-black night sky, and it required 25% Mason 6600
best black to achieve the depth of black I sought.You can see
examples on the "early work" section of the "gallery" page at
mywebsite."
Vince Pitelka on thu 17 apr 08
Paulette Carr wrote:
"Just for my reading pleasure (not to mention, education!), I just re-
read the sections in your book on colored clay: there, you suggest
using a clay body that is not vitreous at low-fire temperature, and
is not a talc body. Is this the clay body that you were using when
you were doing the low-fire work or were you actually using a talc
body? Would you say that the clay body that you were using was at or
near it's maturity when you were working at low-fire temperatures?
It occurred to me that if you are still using those loaves, and you
are now working at ^6, the clay body that you used then may not have
been a talc body (as I assumed), but perhaps the one that you suggest
in your book."
Paulette -
The claybody suggested in my book is actually a midrange porcelaineous
stoneware. At cone 03 it is nowhere close to vitrification, but is quite
dense, and I just liked its working properties. It worked great for the
sculptural forms I was making at the time.
As you may know, true vitrification is pretty much impossible at low-fire
temperatures in a plastic claybody. The closest anyone ever came was with
soft-paste porcelain - the stuff they used in the Baroque era before the
Germans finally discovered the first true porcelain in Europe in 1706.
Soft-paste porcelain was so loaded with glassy frit that it came close to
vitrification at low-fire temperatures, but it was damn near impossible to
work with because it was so non-plastic.
Low-fire talc bodies are appealing for a number of reasons. I tried them
when I was in grad school, and found them too punky and porous for my
purposes, and developed the claybody that is in the book. Now, I just
laminate colored porcelain patterns onto stoneware slabs or coil forms and
soda-fire them to cone 6.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
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