May Luk on tue 2 nov 04
Hi all:
I have to do some engobe slip firing to cone 5 for homework. I have some
silicon carbide I don't know what to do with. [Was going to test reduction
copper red in electric kiln some time in the future] Anybody tried it with
slip? How about starting with 5 % ?
TIA
May
London, UK
Paul Lewing on tue 2 nov 04
on 11/2/04 1:50 PM, May Luk at yamerica@BTOPENWORLD.COM wrote:
> I have to do some engobe slip firing to cone 5 for homework. I have some
> silicon carbide I don't know what to do with. [Was going to test reduction
> copper red in electric kiln some time in the future] Anybody tried it with
> slip? How about starting with 5 % ?
If it reacts anything like it does in a glaze, 5% is guaranteed to give you
a "lava" effect, with huge sharp craters. To do the artificial reduction
thing, 1% is about the upper limit for silicon carbide. And it must be a
very VERY fine powder, at least 300 mesh, or better yet, 1000 mesh.
Paul Lewing, Seattle
Ivor and Olive Lewis on wed 3 nov 04
Dear May Luk,
It is possible to get a violent reaction with Silicon carbide in a
glaze but I am not certain this would happen with a slip. An exception
would be with one which is well vitrified at the firing temperature
which contains a substance that can be reduced.
I have results which are highly cratered due to bubbling through a
viscous melt.
Have fun with your tests,
Ivor Lewis.
Redhill,
S. Australia.
May Luk on wed 3 nov 04
Dear Ivor;
For this project, I have to make incremental addition of frits to the slip
and see when it would get a sheen - plus multiple firing. With what you've
said, I'll be adding some copper oxide and some iron oxide to see the
different effects. Sounds like fun already.
Thanks
May
==========================================
.....An exception would be with one which is well vitrified at the firing
temperature which contains a substance that can be reduced.......
Ivor Lewis.
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