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unexpected results from iron glazes- solved!

updated mon 10 sep 07

 

iglasgo on sun 9 sep 07


Last night I ran a test fire with fast cooling in my little kiln. When
the sitter shut off, I let it cool naturally. I got good, classic
results from my very thick tests of Floating Blue and Cream Breaking
Red. The MC6G Variegated Blue came out a nice color, but heavily
pinholed. Maybe that's because the kiln really only hit ^5, or maybe
it was applied too thickly. Some beautiful and unexpected results
arrived from a couple other glazes that I have been fiddling around
with. My favorite matte came out glossy, though not smooth.

I also put some thinly glazed tests of FB and CBR in this firing. The
FB came out as a navy-blue-brown. Not at all like my previous test,
but not all the way to FB either. The CBR came out red. Cool.

Thanks so much to all the Clayarters who generously shared their
advice and experience.

-Ivy G.

> Gail said:
> "Last week I tried a new firing schedule with a much slower
> cooling period. The spearmint green and licorice pots were just
> beautiful, lots more depth, small crystals, and vibrant color
> than previous firings. And my previous results were just great!
> The variegated blue pots from that firing looked just like your
> test. There was almost no blue at all. Everything was the same
> except the firing schedule."
>
> Aha! I think this might be the real key to my results. I don't have a
> controller, so I fire 'by eye'. After the ^6 in the sitter bends, I
> wait about 30 minutes, then turn the kiln back on at half power and
> hold for four hours, then shut off and cool naturally. At the end of
> the firing the self-supporting ^6 is just touching all shelves. I get
> great results from matte glazes, Licorice, and Waterfall Brown, and
> cute crystals up to 1/2" in a zinc-nickel crystalline glaze. This
> suggests that I'm getting a nice slow cooling.
>
> I have a little kiln that I bought to use as a test kiln but it just
> doesn't fire the same as the big kiln since it cools so much faster.
> My matte glazes come out glossy, crystals don't grow, WFB is boring.
> So I use it only for small batches that are glazed with things that
> like a faster cooling. I will re-test floating blue and variegated
blue in the little kiln.
>
> Thanks for the insights everybody.
> -Ivy G.