David Hendley on sun 18 aug 02
Hi Ron,
I would consider your 3 colorant groups for producing forest green:
> Cobalt carb 1 and chrome oxide 2
> Cobalt carb 1 and Rutile 2
> Copper carb from 2.5 to 6
as 3 different and distinct glaze types.
I would agree with your comment that:
> The first comment is that it does not seem to matter what glaze you use.
> There is nothing common in the flux groupings, the amount of boron or
> alumina or silica.
only with regard to the first colorant group, cobalt and chrome.
High-fire or mid-range, oxidation or reduction, these colorants
will give you green in just about any glaze base that sticks within,
or close to, accepted glaze limit formulas.
Getting green from cobalt and rutile is a different story, and requires
certain characteristics from the glaze base to work.
I have tried to adjust "cobalt green" glazes to change the fit and
expansion and lost the green color in the process (it becomes blue).
As for green copper glazes, they of course require a strict non-reducing
atmosphere in the firing. And, in my experience, these glazes do not
produce the same type of green as the other colorant types. Not really
what I would call "forest green", whatever it is.
For a good, bright color a high potassium glossy base is best.
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com
----- Original Message -----
> I have 3 cone 6 versions and 4 cone 10 versions.
>
> It occurs to me that I do not know exactly what colour Hunter Green is -
I
> suspect it will be at least be somewhat different for every one - I will
> see the results of my findings when I do the workshop in St John's NFD
next
> week end.
> The first comment is that it does not seem to matter what glaze you use.
> There is nothing common in the flux groupings, the amount of boron or
> alumina or silica.
> Not even in the colours used but there were 3 groups
> Cobalt carb 1 and chrome oxide 2
> Cobalt carb 1 and Rutile 2
> Copper carb from 2.5 to 6
> The glaze I am working on is to be fired at cone 8 so I simply used the
two
> glazes which had the right expansions (to not craze) and averaged the mols
> and used that as a guide to construct the new glaze. The aims as usual are
> proper fit and a good chance of a stable glaze.
> RR
>
Ron Roy on mon 19 aug 02
Hi Folks,
Thanks again to those of you who sent hunter green recipes for this project
- David, Leslie, Judy,Cathrine and Marrianne.
I have 3 cone 6 versions and 4 cone 10 versions.
It occurs to me that I do not know exactly what colour Hunter Green is - I
suspect it will be at least be somewhat different for every one - I will
see the results of my findings when I do the workshop in St John's NFD next
week end.
The first comment is that it does not seem to matter what glaze you use.
There is nothing common in the flux groupings, the amount of boron or
alumina or silica.
Not even in the colours used but there were 3 groups
Cobalt carb 1 and chrome oxide 2
Cobalt carb 1 and Rutile 2
Copper carb from 2.5 to 6
The glaze I am working on is to be fired at cone 8 so I simply used the two
glazes which had the right expansions (to not craze) and averaged the mols
and used that as a guide to construct the new glaze. The aims as usual are
proper fit and a good chance of a stable glaze.
I will report again when I have seen the test results - sometime after Aug 29.
RR
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
iandol on tue 20 aug 02
Dear David Hendley,=20
You say...."Not really what I would call "forest green", whatever it =
is"...
Webster's is a wonderful book for giving the low down on the nuances of =
various colours.
To answer your rhetoric, they bring to our attention "Forest Green 1: A =
dark green that is yellower and stronger than Evergreen or average =
Bottle Green. 2: A moderate Olive Green that is greener and deeper than =
Holly Green (Sense 2), yellower, lighter and stronger than Cypress, and =
greener, stronger and slightly darker than Lincoln Green"
Where do we go from here!!!
Best regards,
Ivor.
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