Frank Helme on sun 22 jun 97
I just tested Revision 3 of Cream Breaking Red posted by John Post and what
I call NCECA Green which was posted as "My Green" from Susan Demay at the
97 NCECA. Both results were not what I expected and I am looking for
explanation. I will be off clayart after the 27th for some vacation.
I did a 11 hour oxidation firing to cone 6 at "9 oclock" in a small
electric kiln with an Orton controller (my first use). I did a 15 minute
soak at 2150F because of temperature differences top and bottom in my kiln.
I went to 2212F and soaked until the cone went to 9 oclock. I use Miller
#75 clay which is a red/buff color.
My Green - Did not come out green at all. Was sort of a gray/green/blue
where the glaze was thicker. The edges were plain glossy brown. The glaze
broke significantly on the edges and had a tendency to run.
Cream Breaking Red #3 - Glaze was very smooth and broke on edges but it was
more of a light tan with a touch of green rather than a cream breaking red.
Hard.
Creak Breaking Red original - I find this glaze to be very sensitive to
something; either heat work or thickness. I got one great test tile but
the others tended to be very brown and the last firing had the glaze
apparently separate into tiny blobs of green? in a light tan horrible mess.
Any help would be appreciated. Is thickness the problem or excessive heat
work.
NCECA Green: custer 40.74, zinc oxide 4.63, gerstley 17.60, dolomite 5.60,
whiting 1.85, epk 4.63, flint 17.6, copper carb 2.78, RIO 1.85, rutile
2.78.
CBR #3: frit 3134 30.6, custer 26.6, wollastonite 10.6, talc 2.3, strontium
carb 3.3, epk 8.4, flint 18.2, RIO 6 , tin oxide 13.
frank helme in upstate ny
fhelme@worldnet.att.net
John Post on mon 23 jun 97
Hi Frank,
I find that the glaze has more interesting color and
rust-speckling/breaking if applied on the thin side. The color that
I get is more of a cream breaking RUST and not a true red.
If it is applied very thick the glaze is a solid cream color and
there is no speckling as the glaze only breaks rust over the edges.
I have seen some glazes that are high in iron look slightly
greenish when they get thick. This might be what is happening in
your case.
I fire over a white body. Your red/buff body may also be causing
some color changes in the glaze.
John Post
rp1mrvl@moa.net
> ----------------------------Original message----------------------------
> I just tested Revision 3 of Cream Breaking Red posted by John Post ...
> results were not what I expected and I am looking for
> explanation.
> I did a 11 hour oxidation firing to cone 6 at "9 oclock" in a small
> electric kiln with an Orton controller (my first use). I did a 15 minute
> soak at 2150F because of temperature differences top and bottom in my kiln.
> I went to 2212F and soaked until the cone went to 9 oclock. I use Miller
> #75 clay which is a red/buff color.
> Cream Breaking Red #3 - Glaze was very smooth and broke on edges but it was
> more of a light tan with a touch of green rather than a cream breaking red.
> Hard.
> Is thickness the problem or excessive heat work.
> CBR #3: frit 3134 30.6, custer 26.6, wollastonite 10.6, talc 2.3, strontium
> carb 3.3, epk 8.4, flint 18.2, RIO 6 , tin oxide 13.
>
> frank helme in upstate ny
> fhelme@worldnet.att.net
>
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