Michele Williams on sun 21 apr 02
Lee wrote:
> You can control where the carbon trapping black goes by using wax =
resist.
> Where ever you put the resist, the black is absent.
I know he was talking about shino glazing. Does anyone (or everyone but =
me) know whether when I'm doing the kilnless firing as the Hopi Indians =
do or as Snail suggests in a flowerpot, would I be able to use lowfire =
white clay, wax pieces all over, and be able to assure that the final =
outcome would be white? Or would the smoke get to the pot during =
cooling anyway? I love black pots, but I have a small quantity of white =
clay that I'd like to keep white throughout the process.
Michele Williams
Jeff Tsai on mon 22 apr 02
Michele,
Wax resist over a hopi indian firing in the attempts to achieve a black
shiny
pot will not give you a white pot. The wax resist will melt off a long time
before the firing begins trapping carbon into the work.
Wax resist works with shinos because of an ingredient inside of shinos
called
soda ash (or just sodium) that affects the final outcome of the glaze. The
wax affects how the sodium becomes distributed over the surface of the
glaze.
However, you can get a fairly white pot in a traditional kilnless firing. I
assume the method (I have not kept up with every post) you are suggesting is
probably similar to placing your work on a grate of some sort with an
overturned flower pot. You then pile up cow pies around the piece and burn
it
right?
If this is the method being used, then simply lift the flower pot off the
ground a few inches. Do not seal the flowerpot off so that air cannot enter,
use some bricks (3) to lift the flower pot a few inches off the ground so
that air can easily enter into the space containing your piece. The reason a
piece would go black, or dark is because there is no oxygen being allowed
into the fire. You may not get a bright bright white pot, but maybe
off-white
or tan. The higher the flower pot is raised, the more air, and the less
likely you will get darkened clay.
-jeff
Ann Geiger on mon 22 apr 02
Does anyone (or everyone but me) know whether when I'm doing the kilnless
firing as the Hopi Indians do or as Snail suggests in a flowerpot, would I
be able to use lowfire white clay, wax pieces all over, and be able to
assure that the final outcome would be white? Or would the smoke get to the
pot during cooling anyway? I love black pots, but I have a small quantity
of white clay that I'd like to keep white throughout the process.
Michelle, from my very limited experience, if you have the pots right in the
coals the carbon will burn off and the pots will come out almost white. The
breakage is a bit heavier though. Of course, if I hadn't stirred the coals
with a poker...
Also, if you put the pots in a saggar, without holes, Then the smoke cannot
get in to make the pots black. I think a cookie tin would do it. I do not
know if one hole in the top of the saggar is needed to let the hot air out.
However there are many on the list who are experts on that :>).
Regards,
Annie Geiger
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Snail Scott on mon 22 apr 02
At 03:11 PM 4/21/02 -0400, you wrote:
>...(or everyone but me) know whether when I'm doing the kilnless firing as
the Hopi Indians do or as Snail suggests in a flowerpot, would I be able to
use lowfire white clay, wax pieces all over, and be able to assure that the
final outcome would be white? Or would the smoke get to the pot during
cooling anyway?
You can use the white clay and keep it white if you
like. For that, just introduce a bit of a draft though
the firing toward the end, to burn out all the smoke.
To make it black, just keep it smothered. For black
and white together, you sort of combine methods. It
may take a little practice to get a firing to be
all white or all black; a little of both is easy!
Those Mata Ortiz pots with the elaborate painting and
colored clays are done that way - nice and clean. No
smoke unless you want it, though it may take a little
practice. And, if you don't like the first result,
you can refire the piece and change it completely!
To get only certain areas to stay white, I doubt
that wax resist would help; it will just burn away.
You could try a resist slip (see archives for 'dry
raku' posts). Or, paint the black areas with
underglaze, and follow the 'whiteware' firing method.
-Snail
Michele Williams on mon 22 apr 02
Thanks, Ann. I have done one whole saggar firing in the electric kiln, and
it went well. But the electric kiln doesn't produce smoke.....
I appreciate your tips. I'll try a foil saggar and see what happens!
Michele Williams
> Also, if you put the pots in a saggar, without holes, Then the smoke
cannot
> get in to make the pots black.
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