Mayssan Shora Farra on fri 10 mar 06
Hello Karin:
I have no idea about oil spot glazes, but I added the ingredients up and
they accounted for 100.03 % so I cannot see where anything would be
missing except maybe colorants if it had any.
happy glazing
Mayssan
Karin Hurt on fri 10 mar 06
I have a recipe from the ClayArt Glaze Database with the name of:
Yuteki (Oilspot) Tenmoku
Cone 9-10
firing: Untested
date: 4/21/95
under "Percentage Analysis for Yuteki (Oilspot) Tenmoku I think there is an ingredient or two missing as the page ends abruptly. Here is what is listed:
74.35 % Si02
11.59 % Al203
6.90 % K20
1.98 % na20
3.71 % CaO
1.50 % MgO
can someone tell me what is missing here? Thank you in advance.
Karin
Karin Hurt
www.laughingbearpottery.com
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David Hewitt on sat 11 mar 06
Karin,
What you quote adds up to 100 so I think that it is complete except for
the Red Iron Oxide which is necessary for oil spot.
Also the analysis looks a possible oil spot.
I would expect that you would need to add about 6% synthetic RIO, but
only testing will prove this. I would try a line blend on some test
tiles first.
Also from my experience of oil spot, the firing is important. In
oxidation I give a 1/2 hour soak and fire down slowly - only drop 150 C
in the first hour. My experience, though, is with a different recipe,
so I cannot say that this firing regime is correct for your recipe.
David
In message , Karin Hurt writes
>I have a recipe from the ClayArt Glaze Database with the name of:
>
> Yuteki (Oilspot) Tenmoku
> Cone 9-10
> firing: Untested
> date: 4/21/95
>
> under "Percentage Analysis for Yuteki (Oilspot) Tenmoku I think there
>is an ingredient or two missing as the page ends abruptly. Here is what
>is listed:
>
> 74.35 % Si02
> 11.59 % Al203
> 6.90 % K20
> 1.98 % na20
> 3.71 % CaO
> 1.50 % MgO
>
> can someone tell me what is missing here? Thank you in advance.
>
> Karin
>
>
>Karin Hurt
>www.laughingbearpottery.com
>
>
>---------------------------------
> Yahoo! Mail
> Use Photomail to share photos without annoying attachments.
--
David Hewitt
Web:- http://www.dhpot.demon.co.uk
Ivor and Olive Lewis on sun 12 mar 06
Dear Karin Hurt,
Since the sum of the ingredient percentages is close to 100, nothing =
missing as far as the base glaze is concerned.
Also note that the author of this glaze has not proven its worth. So its =
ability to throw "Oil Spots" is speculative
Seger calculations rarely incorporate Colouring oxides. You will need to =
line blend Red Iron Oxide (Fe2O3) with this base. I suggest 1% =
increments from 5% to 15%.
Fire to Cone 10 or higher with a neutral to oxidising atmosphere all the =
way to the top.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
.
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