Michele Hoskin on fri 9 apr 99
Hi again.
I am answering my own questions as I learn insight. I figure I can add to
the MDT in insight if I figure out the mol. composition of copper oxide.
Now, where to find this?!!!
I have now used insight to alter a clear matt recipe to have the same
expansion as my reliable great fitting clear glaze. I am assuming that
expansion is most important here. The new glaze is:
Silica 32.5
Gerstley Borate 33
EPK 28.5
Alumina Hydrate 6
It has an expansion of 5.94 which my reliable glaze has and totals 100.
Should this be OK for cone 6 stoneware in oxidation?? The limits don't
seem perfect but they aren't for my reliable glaze either.
Thanks for the help,
Michele Hoskin
Toronto
Gavin Stairs on sat 10 apr 99
At 11:10 AM 4/9/99 EDT, you wrote:
>----------------------------Original message----------------------------
>
>Hi again.
>
>I am answering my own questions as I learn insight. I figure I can add to
>the MDT in insight if I figure out the mol. composition of copper oxide.
> Now, where to find this?!!!
Hi Michelle,
Just a couple of quicky note on your questions:
Copper oxide:
2 types, Black oxide, CuO, and yellow (brown, red) oxide Cu2O. Also sold
as the carbonate, CuCO3, I believe.
Insight and most other programs do not include the colorant oxides in their
expansion and base glaze calculations. The reasoning is that they are
added in small enough amounts that they can be ignored, and the same base
can be used for many variants without reformulation. This is usually
acceptable, but there are exceptions.
So, at least to begin with, calculate your glaze without colorants, and
then add them later. Look at some old posts by Ron Roy to see how it is done.
Gavin
David Hewitt on sun 11 apr 99
In message , Gavin Stairs writes
>
>Insight and most other programs do not include the colorant oxides in their
>expansion and base glaze calculations. The reasoning is that they are
>added in small enough amounts that they can be ignored, and the same base
>can be used for many variants without reformulation. This is usually
>acceptable, but there are exceptions.
>
If it is of interest, MATRIX, GLAZECHEM and my GLAZE WORKBOOK all
include colouring oxides
David
>So, at least to begin with, calculate your glaze without colorants, and
>then add them later. Look at some old posts by Ron Roy to see how it is done.
>
>Gavin
>
--
David Hewitt
David Hewitt Pottery ,
7 Fairfield Road, Caerleon, Newport,
South Wales, NP6 1DQ, UK. Tel:- +44 (0) 1633 420647
FAX:- +44 (0) 870 1617274
Own Web site http://www.dhpot.demon.co.uk
IMC Web site http://digitalfire.com/education/people/hewitt.htm
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