Jill Whitfill on tue 1 apr 08
Hi All you great clayarts folks!! What a wonderful day........so far. "-)
I love a glaze called Turner's Beauty but I only have experienced it at a
^10 gas reduction. I would like to try it at ^6 electric kiln. Two
question: Has anyone done such and do I change anything in the
ingrediants? Here is the recipe:
Custer Feldspar 30 or G200 30
Spondumene 20
Dolomite 22
Whiting 2
EPK Kaolin 20
Tin Oxide 6
Any input would be greatly appreciated.....I am really new at this so be
gentle. "-)
Thanks,
jill
Steve Slatin on tue 1 apr 08
Jill -
The easiest thing, unfortunately, is to find a similar
effect glaze in ^6 oxidation, and tinker with it until
it does what you want.
Here's the skinny on Turner's Beauty, though.
It's a *very* low silica to alumina ratio glaze. That
means that it relies on lots of heat and lots of
flux to melt the extremely large amount of
alumina in it.
At cone 6, you can't readily melt that much
alumina. In terms of absolute quantity of alumina
in the glaze, at cone 6 only 'shino' type glazes
(Selsor's Shino, 'American Shino' and so on)
carry that much alumina, and many are not
completely melted.
The usual tricks -- replacing the feldspar with
Frit 3134 or Gerstley Borate or Gillespie
Borate, or leaving the feldspar the same and
adding 10% Gerstley Borate probably won't
work.
I don't know if you have used the Seger
formula (AKA Unity formula) for analysis,
but this is a good example of how it can
conceal an issue instead of revealing it.
Under Seger, the alumina in this recipe is
.494 -- high, but under the limit for cone 6.
Silica is 1.998; below the usual 'limit' but
not in the range where good glazes are rarely
or never found.
But the reason why this happens is because
the mix of fluxes *and* the total flux concentration
are both out of the normal range. Total fluxes
are 28.57% by molar concentration, with lots
of the fluxes being weak melters -- calcium and
magnesium. That alumina that under Seger
seems OK? By molar concentration, it's just
too high. And the silica that seemed too low?
Well, it is barely 57% of the total, and there
are virtually no other possible glass formers.
I've never used this glaze, have little experience
with ^10 glazes and less with reduction -- but
I am fairly comfortable with ^6 oxidation. I doubt
seriously that you can make a stable, reliable
glaze starting from here.
Because I don't know what it is you're looking
for I can't say what will get you there, but
Marcia Selsor's ^6 oxidation shino has some
similar 'themes' in it, and gives a pretty tan
color range. I'm guessing the "Turner's Beauty"
is somewhere in the range of that to yellow,
depending on clay body and so on. I have
not tested it for stability/durability, but the
surface is not what you'd want for tableware
anyway.
Best wishes -- Steve Slatin
Jill Whitfill wrote:
Hi All you great clayarts folks!! What a wonderful day........so far. "-)
I love a glaze called Turner's Beauty but I only have experienced it at a
^10 gas reduction. I would like to try it at ^6 electric kiln. Two
question: Has anyone done such and do I change anything in the
ingrediants? Here is the recipe:
Custer Feldspar 30 or G200 30
Spondumene 20
Dolomite 22
Whiting 2
EPK Kaolin 20
Tin Oxide 6
Any input would be greatly appreciated.....I am really new at this so be
gentle. "-)
Thanks,
jill
---------------------------------
You rock. That's why Blockbuster's offering you one month of Blockbuster Total Access, No Cost.
Ron Roy on fri 4 apr 08
Hi Jill,
Try this - remember to slow cool it if you want the matt effect. If you
have any chrome cloured glazes in with it you will get pink flashing
because of the tin - you might even get that if you have been firing chrome
glazes cause it gets into the kiln bricks.
Anyway try it and get back to me with the results - it may need to tweaking.
RR
Untitled Recipe 2
-----------------
CUSTER SPAR (or G200) ......... 4.00
SPOD........... 24.00
F3134............... 20.00
DOLOMITE............ 18.00
TALC................ 6.00
EPK................. 22.00
TIN................. 6.00
----------
100.00
RATIO 4.55
EXPAN 407.03
WEIGHT 207.70
Don't forget to include the original glaze and my revision - I'm not saving
them.
RR
>Hi All you great clayarts folks!! What a wonderful day........so far. "-)
>I love a glaze called Turner's Beauty but I only have experienced it at a
>^10 gas reduction. I would like to try it at ^6 electric kiln. Two
>question: Has anyone done such and do I change anything in the
>ingrediants? Here is the recipe:
>Custer Feldspar 30 or G200 30
>Spondumene 20
>Dolomite 22
>Whiting 2
>EPK Kaolin 20
>Tin Oxide 6
>
>Any input would be greatly appreciated.....I am really new at this so be
>gentle. "-)
>
>Thanks,
>jill
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Jill Whitfill on fri 4 apr 08
On Fri, 4 Apr 2008 00:08:40 -0500, Ron Roy wrote:
>Hi Jill,
>
>Try this - remember to slow cool it if you want the matt effect. If you
>have any chrome cloured glazes in with it you will get pink flashing
>because of the tin - you might even get that if you have been firing
chrome
>glazes cause it gets into the kiln bricks.
>
>Anyway try it and get back to me with the results - it may need to
tweaking.
>
>RR
>
> Untitled Recipe 2
> -----------------
> CUSTER SPAR (or G200) ......... 4.00
> SPOD........... 24.00
> F3134............... 20.00
> DOLOMITE............ 18.00
> TALC................ 6.00
> EPK................. 22.00
> TIN................. 6.00
> ----------
> 100.00
>
> RATIO 4.55
> EXPAN 407.03
> WEIGHT 207.70
>
>Don't forget to include the original glaze and my revision - I'm not
saving
>them.
>
>RR
>
>
>>Hi All you great clayarts folks!! What a wonderful day........so far. "-)
>>I love a glaze called Turner's Beauty but I only have experienced it at a
>>^10 gas reduction. I would like to try it at ^6 electric kiln. Two
>>question: Has anyone done such and do I change anything in the
>>ingrediants? Here is the recipe:
>>Custer Feldspar 30 or G200 30
>>Spondumene 20
>>Dolomite 22
>>Whiting 2
>>EPK Kaolin 20
>>Tin Oxide 6
>>
>>Any input would be greatly appreciated.....I am really new at this so be
>>gentle. "-)
>>
>>Thanks,
>>jill
>
>Ron Roy
>RR#4
>15084 Little Lake Road
>Brighton, Ontario
>Canada
>K0K 1H0
>
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Hi Ron,
Thanks for your reply about Turner's Beauty. I wonder about the flashing
issue. So how do I know if a glaze has chrome in it? Will it burn out of
the brick or is it there to stay? I am very new at this so please forgive
my ignorance on the topic.
Thank You,
Jill Whitfill
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