Veena Raghavan on sun 11 dec 05
Dear Clayarters
With all the talk about Potassium chromate and dichromate (and I already know
that these are very dangerous to use), I would appreciate it if our experts
could tell us if iron chromate is safe to use with the usual precautions in
using metal oxides and so on. Is the chrome in iron chromate also very high, as
it is in Potassium chromate.
Thank you in advance for your help.
I would also like to take this opportunity to wish everyone very Happy
Holidays and a very Happy New Year, and to thank everyone for all the wonderful
information on Clayart. Thank you all and thank you Mel.
Veena
VeenaRaghavan@cs.com
Ivor and Olive Lewis on mon 12 dec 05
Dear Veena ,
I am wondering why anyone would ever wish to use Iron Chromate in a =
glaze ! !
I can see it may have a use for putting dark speckles in a clay body, =
but in a glaze, never would I think of using it! ! !
Logic and experience tell me that Chromium oxide will give a green, Iron =
Oxide with give a red to red orange. These are colours which cancel and =
give a tone, grey to black.
The only time there might be a beneficial colour response would be in =
intense oxidising conditions when the iron gave yellow so that the hue =
became lime green or in intense reduction were the iron gave a blue so =
that the hue was green blue. But that is only "Supposition"
Have a great time over the festive season.
Best regards,
Ivor
Des & Jan Howard on fri 16 dec 05
Ivor
Chromium oxide will also give pinks with tin & high temp reds with
lithium ( I'm told), while iron oxide will produce browns, purples,
blues, greens, yellows all in reduction.
I just ran GlazeChem using iron chromate as a substitute for the 1%
local ochre & 0.13% chrome oxide in our apple celadon, looks easy
peasey. Will try it next firing.
Des
Ivor and Olive Lewis wrote:
>I am wondering why anyone would ever wish to use Iron Chromate in a glaze ! !
>
>I can see it may have a use for putting dark speckles in a clay body, but in a glaze, never would I think of using it! ! !
>
>Logic and experience tell me that Chromium oxide will give a green, Iron Oxide with give a red to red orange. These are colours which cancel and give a tone, grey to black.
>
>The only time there might be a beneficial colour response would be in intense oxidising conditions when the iron gave yellow so that the hue became lime green or in intense reduction were the iron gave a blue so that the hue was green blue. But that is only "Supposition"
>
>
--
Des & Jan Howard
Lue Pottery
LUE NSW 2850
Australia
Ph/Fax 02 6373 6419
http://www.luepottery.hwy.com.au
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