Judy Rohrbaugh on mon 17 jul 06
I have made a few horsehair raku pots. I burnished the pots and bisqued to about
come 08.
I am happy with the results.
But I wondered if they could be bisqued a bit
higher. without losing the burnished smoothness.
So far, I am not using any terra sig, just burnishing with a spoon.
Thank you,
Judy Rohrbaugh
Fine Art Stoneware
Ohio
Snail Scott on mon 17 jul 06
At 05:02 AM 7/17/2006 -0700, you wrote:
>I have made a few horsehair raku pots. I burnished the pots and bisqued to
about
> come 08.
> I am happy with the results.
> But I wondered if they could be bisqued a bit
> higher. without losing the burnished smoothness...
It's an incremental loss. When people say,
"don't fire burnished stuff above ^012", or
^010, or whatever, it's not some magic number
and above that temperature it suddenly turns
to sandpaper, but it will be less shiny the
higher you fire. The effects of burnishing can
even be visible (barely) at stoneware
temperatures, though it may not be worth the
effort for that faint, diminished effect.
It's up to you to find your preferred balance
between strength and shine.
-Snail
William Lucius on tue 18 jul 06
Archeologists and replicators call it polishing and instead of spoons or =
other metal objects we use smooth rocks (polishing stones) for surface =
compaction. Keep in mind that I use only native (as opposed to =
commercial) clays but it has been my experience that in oxidation most =
iron rich earthenware clays will tolerate Cone 07 oxidation (1008 C), =
although at that temperature the bright polish goes somewhat matt. At =
the same temperature in a neutral to slightly reducing atmosphere that =
is the target of our replication pit firings the iron rich red clays =
vitrify and lose their polish entirely, whereas the more refractory =
white burning clays are quite stable with polish that reflects light =
when held up to the light.=20
While composing this reply I inspected a recently fired organic paint =
Black-on-white bowl and I noticed highly polished areas that correspond =
to where I used the eraser of a standard No. 2 pencil to obliterate =
design layout lines that I had sketched in pencil. I would have never =
thought about using an eraser as a polishing tool! I will have to try =
it on other white slips to see if it works on them. =20
William A. Lucius, Board President
Institute for Archaeological Ceramic Research
845 Hartford Drive
Boulder, CO 80305
iacr@msn.com
pdp1@EARTHLINK.NET on wed 19 jul 06
Hi William,
Well, Pencil or Ball Point Pen Erasers, are made
of a Rubber which contines, or at least used to
contain, a finely pulverised Glass.
In effect, they are indeed a ready abrasive of
sorts...but not a Burnisher, which to be a
Burnisher, will be smoothe and hard.
If you like the effect of the Eraser, you might
consider to try Silicon Carbide Abrasive Paper,
useing it 'wet', with a slightly Soapy Water to
carry off the abraded material and also prevent it
from being airborne at the time. This for already
bisque or fired Work of course...
If you are wishing to abrade a Glaze, then of
course you would use the abrasive paper 'dry' and
have some way not to be breathing the very fine
dusts being made.
The papers of course come in a wide array of grit
size...up to 1000 grit I think.
Certainly a 400 or 500 or 600 grit would give you
a nice effect, and be likely be finer than most
Erasers...
Phil
Las Vegas
----- Original Message -----
From: "William Lucius"
Archeologists and replicators call it polishing
and instead of spoons or other metal objects we
use smooth rocks (polishing stones) for surface
compaction. Keep in mind that I use only native
(as opposed to commercial) clays but it has been
my experience that in oxidation most iron rich
earthenware clays will tolerate Cone 07 oxidation
(1008 C), although at that temperature the bright
polish goes somewhat matt. At the same
temperature in a neutral to slightly reducing
atmosphere that is the target of our replication
pit firings the iron rich red clays vitrify and
lose their polish entirely, whereas the more
refractory white burning clays are quite stable
with polish that reflects light when held up to
the light.
While composing this reply I inspected a recently
fired organic paint Black-on-white bowl and I
noticed highly polished areas that correspond to
where I used the eraser of a standard No. 2 pencil
to obliterate design layout lines that I had
sketched in pencil. I would have never thought
about using an eraser as a polishing tool! I will
have to try it on other white slips to see if it
works on them.
William A. Lucius, Board President
Institute for Archaeological Ceramic Research
845 Hartford Drive
Boulder, CO 80305
iacr@msn.com
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