Ian Currie on mon 31 mar 08
From: Mike
> I've been doing some experiments in trying to get an oribe green that
> doesn't run off the pots at my normal firing temp, so I did a currie
> grid. I noticed that as one gets into the A and B corners of the grid,
> the color turns black brown, whereas the C and D corners show good
> colorant color. In this case it was copper. Looking in revealing
> glaze I
> saw some other grids with colorants showing the same color loss in the
> alumina rich areas. What is the reason for this? Am I right in
> assuming
> it's the alumina that's causing the color loss?
Hi Mike... this is correct. Sure there are some colours that need
high alumina, like shino-red for example, but many grids show a loss
of colour, or the trend towards earthy colour, as you increase
alumina... like celadons, alkaline copper turquoise, and also the
oribe green.
> The reason I ask is that
> the ideal viscosity for me is at the center of the grid (no.18) or
> possibly no. 23 (a bit runny), but no.18's color is somewhat darker
> than
> I'm looking for and no. 23 has good color but is a bit runny. I'm
> wondering if, with all other ingredients unchanged, I can take the no.
> 18 recipe and just reduce the alumina in increments to get closer
> to the
> color I want.
What you are suggesting here is simply moving down the grid... which
is where you started, with good colour but runny. I think this is
the deal if you want a reasonably genuine oribe green... the old ones
were quite runny.
It was nice catching up with lots of old friends at NCECA in Pittsburgh.
Warmest regards
Ian
Ian Currie
"Mandala"
831 North Branch Road
Maryvale, Q. 4370
Australia
Ph: +61 7 4666 1237
http://glazes.org
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