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weird two-tone raku

updated fri 14 apr 06

 

Teri Lee on wed 12 apr 06


Hi,

Has anyone ever had raku pots come out with two tones as if they were cut
in half, so that the top half of the pot is a slightly different color
(glazed as well as black non-glazed sections) than the bottom?

I've brushed on terra sig, per Marcia Selsor's suggestion, to see if that
solves the problem, and am waiting for that batch of pots to come out of
the bisque. But in the meantime, I thought that maybe I've been bisquing at
too low a temperature, so that I'm actually burnishing the bottom half of
my pot when I trim? What temp do folks tend to bisque for raku? I'm
bisquing at ^06.



Teri Lee
Director, Strategic Communications
Mathematics, Engineering, Science Achievement (MESA)
300 Lakeside Drive, 7th Floor
Oakland, CA 94612-3550
PH: (510) 987-9356
FAX: (510) 763-4704
http://mesa.ucop.edu

Elizabeth Priddy on wed 12 apr 06


especially if you are throwing,
the millimeters difference from the top and the
bottom in thickness could cause this.

if this is your culprit, the bottom reduced areas
will be darker than the top half.
E


Elizabeth Priddy

Beaufort, NC - USA
http://www.elizabethpriddy.com

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Marcia Selsor on wed 12 apr 06


Teri,

I bisque at ^09 when using terra sig. Just what exactly and when are
you seeing 2 colors?
Is this after the raku firing or after the bisque?

Marcia Selsor
http://marciaselsor.com


On Apr 12, 2006, at 11:14 AM, Teri Lee wrote:

> Hi,
>
> Has anyone ever had raku pots come out with two tones as if they
> were cut
> in half, so that the top half of the pot is a slightly different color
> (glazed as well as black non-glazed sections) than the bottom?
>
> I've brushed on terra sig, per Marcia Selsor's suggestion, to see
> if that
> solves the problem, and am waiting for that batch of pots to come
> out of
> the bisque. But in the meantime, I thought that maybe I've been
> bisquing at
> too low a temperature, so that I'm actually burnishing the bottom
> half of
> my pot when I trim? What temp do folks tend to bisque for raku? I'm
> bisquing at ^06.
>
>
>
> Teri Lee
> Director, Strategic Communications
> Mathematics, Engineering, Science Achievement (MESA)
> 300 Lakeside Drive, 7th Floor
> Oakland, CA 94612-3550
> PH: (510) 987-9356
> FAX: (510) 763-4704
> http://mesa.ucop.edu

Teri Lee on thu 13 apr 06


Hi, Marcia,

I see the two tones after the raku firing. Everything looks normal after
the bisque, but after the raku firing I get a dividing line which appears
to begin at my trim line. The black, unglazed parts of the pot are darker,
and the glazes are darker too---just a SHADE darker, but enough to make the
pot two-toned and make me crazy.

Date: Wed, 12 Apr 2006 16:11:10 -0600
From: Marcia Selsor
Subject: Re: Weird two-tone raku

Teri,

I bisque at ^09 when using terra sig. Just what exactly and when are
you seeing 2 colors?
Is this after the raku firing or after the bisque?

Marcia Selsor
http://marciaselsor.com


On Apr 12, 2006, at 11:14 AM, Teri Lee wrote:

> Hi,
>
> Has anyone ever had raku pots come out with two tones as if they
> were cut
> in half, so that the top half of the pot is a slightly different color
> (glazed as well as black non-glazed sections) than the bottom?
>
> I've brushed on terra sig, per Marcia Selsor's suggestion, to see
> if that
> solves the problem, and am waiting for that batch of pots to come
> out of
> the bisque. But in the meantime, I thought that maybe I've been
> bisquing at
> too low a temperature, so that I'm actually burnishing the bottom
> half of
> my pot when I trim? What temp do folks tend to bisque for raku? I'm
> bisquing at ^06.
>

Marcia Selsor on thu 13 apr 06


It may have something to do with surface salts in the drying before
you trim, if the
area affected is at your trimming surface. Or it may be your water
affecting the surface before you trim.
It is weird..
Marcia
Marcia Selsor
http://marciaselsor.com


On Apr 13, 2006, at 9:14 AM, Teri Lee wrote:

> Hi, Marcia,
>
> I see the two tones after the raku firing. Everything looks normal
> after
> the bisque, but after the raku firing I get a dividing line which
> appears
> to begin at my trim line. The black, unglazed parts of the pot are
> darker,
> and the glazes are darker too---just a SHADE darker, but enough to
> make the
> pot two-toned and make me crazy.

Marcia Selsor
http://marciaselsor.com