David Hendley on wed 15 oct 03
I love blue, always have, since my nursery was decorated in
anticipation of a bouncing baby boy.
I make close to half of my pots blue, and the ones that are not blue have
spots or lines of blue on them. But, I very rarely use cobalt blue glazes.
I would never use a glaze with cobalt as the only colorant.
If you want the cobalt blue look, at least add 2% red iron oxide to the
glaze so it will not be so garish and harsh.
If you want an aqua blue, add chrome oxide to the glaze in double the
percentage of the cobalt carbonate.
If you want turquoise blue, use a zirconium vanadium stain.
For blue overglaze decoration, I recommend Cardew's blue pigment,
from 'Pioneer Pottery':
cobalt carbonate 20
tin oxide 20
manganese dioxide 10
talc 10
red clay (Redart) 15
kaolin 20
red iron oxide 5
Best of all the blue glazes are the rich, variegated rutile (or titanium)
blues.
My favorite blue glaze is my copper red glaze "Simply Red", with the
addition of rutile. This glaze is sensitive to kiln conditions and will vary
from firing to firing and place to place in the kiln, so it is always
exciting.
There is always that hint of red trying to peek through, and, most
interestingly, if I break a piece and study the glaze matrix from the side,
the underlying glaze, below the surface, is always red.
I think even Mel likes the blue plates I made for him. I haven't gotten
the nerve to give Ron Roy a blue mug yet.
David Hendley
david@farmpots.com
http://www.farmpots.com
Jan Goodland Metz on wed 15 oct 03
To what cone can I fire this glaze?
Thanks
Jan
in windy rhode island.
David Hendley wrote:
>
>For blue overglaze decoration, I recommend Cardew's blue pigment,
>from 'Pioneer Pottery':
>cobalt carbonate 20
>tin oxide 20
>manganese dioxide 10
>talc 10
>red clay (Redart) 15
>kaolin 20
>red iron oxide 5
>
>
>
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>
David Hendley on wed 15 oct 03
This is not a glaze. It is a pigment for painting over a glaze.
It would be dry and unmelted if used as a glaze. I use it at cone 10,
but I imagine it would be good to use at cone 6, and probably
even a few cones lower. The glaze it is painted over, of course,
determines how it turns out to a great degree.
David Hendley
david@farmpots.com
http://www.farmpots.com
----- Original Message -----
> To what cone can I fire this glaze?
> Thanks
> Jan
> >For blue overglaze decoration, I recommend Cardew's blue pigment,
> >from 'Pioneer Pottery':
> >cobalt carbonate 20
> >tin oxide 20
> >manganese dioxide 10
> >talc 10
> >red clay (Redart) 15
> >kaolin 20
> >red iron oxide 5
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