rickmahaffey on tue 5 dec 00
Ivor wrote:
Books about glazing =
tell us that iron gives yellow, orange, black and brown in oxidation and
=
green blues in reduction. So, who can explain orange in reduction? If =
the colour is not from Iron, just what is going on?
Ivor,
The orange color is from the Iron being re-oxidized on cooling. In a
kiln where an Iron bearing clay comes out red, orange or brown it is
because of the infiltration of air. That is why under a well reduced
clear glaze the clay is gray. It stays gray because the air can not get
through the glaze layer.
By the way, you can achieve the same orange clay color by coating an
area of a pot with a super saturated solution of salt (sodium chloride).
Rick Mahaffey
Tacoma Community College
Tacoma, Washington, USA
pedresel on thu 7 dec 00
I do believe this but I also wonder why I can't get that nice toasty
orange color in an oxidation fire. Why does the same clay that is
orange in reduction (reoxidation) a blah tan in oxidation?
-- Evan in W. Richland WA who is ready for the solstice.
rickmahaffey wrote:
>
> Ivor wrote:
> Books about glazing =
> tell us that iron gives yellow, orange, black and brown in oxidation and
> =
> green blues in reduction. So, who can explain orange in reduction? If =
> the colour is not from Iron, just what is going on?
>
> Ivor,
> The orange color is from the Iron being re-oxidized on cooling. In a
> kiln where an Iron bearing clay comes out red, orange or brown it is
> because of the infiltration of air. That is why under a well reduced
> clear glaze the clay is gray. It stays gray because the air can not get
> through the glaze layer.
>
> By the way, you can achieve the same orange clay color by coating an
> area of a pot with a super saturated solution of salt (sodium chloride).
>
> Rick Mahaffey
> Tacoma Community College
> Tacoma, Washington, USA
>
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Hank Murrow on fri 8 dec 00
>I do believe this but I also wonder why I can't get that nice toasty
>orange color in an oxidation fire. Why does the same clay that is
>orange in reduction (reoxidation) a blah tan in oxidation?
>
>-- Evan in W. Richland WA who is ready for the solstice.
Evan;
You need to get the iron reduced and into its mode as a flux first, then it
will be re-oxidized in the cooling(if you give it enough time), and turn to
the warm colors you prefer.
Hank in Eugene
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