Alisa og Claus Clausen on mon 25 jun 01
Glaze test for M. Barringer Metalic Black, cone 6, ox.
Source: Ceramics Montly, April 2001.
Tested on light, mid-range stoneware, with iron flecks. Fired to 1215c =
(22219) oxidation, at this ramp:
100c to 600c 212f to 1112f
150c to 1100c 300f to 2012f
100c to 1220c 212f to 2228f
soak at 1220c for 30 minutes =20
cool down 100c per hour to 900c (212f/1652f)=20
soak at 900c for one hour
shut off and cool down (aprox. 40 hours)
Recipe:
10.75 Gersltey Borate
5.48 Whiting
78.86 Feldspar
4.91 Kaolin
Add
2.07 Cobalt oxide
4.14 Copper carb.
4.14 Manganese Diox.
All raw materials, with the exception of colorants, measured up or down =
to the nearest whole decimal.
Substitutions: None.
Resulted in a thick and covering metalic black. The truest black grey =
metallic black I have tried. Very
good covering and smooth surface.
Best regards,
Alisa in Denmark
John Hesselberth on mon 25 jun 01
on 6/25/01 11:06 AM, Alisa og Claus Clausen at aliskin@MAIL.DK wrote:
> Glaze test for M. Barringer Metalic Black, cone 6, ox.
>
> Source: Ceramics Montly, April 2001.
>
> Recipe:
> 10.75 Gersltey Borate
> 5.48 Whiting
> 78.86 Feldspar
> 4.91 Kaolin
>
> Add
> 2.07 Cobalt oxide
> 4.14 Copper carb.
> 4.14 Manganese Diox.
>
>
> Resulted in a thick and covering metalic black. The truest black grey
> metallic black I have tried. Very
> good covering and smooth surface.
Just a quick note on this glaze. The recipe is virtually identical to one
published by Carlton Ball and Janet Lovoos on page 144 in their 1965 book
Pottery without a Wheel. I have tested it extensively. It is very unstable
and, for me, has a tendency to "spit" all over the kiln. It is definitely
NOT a good functional glaze, probably because it is not fully melted at cone
6 AND because it is overloaded with colorants.
Regards, John
Web site: http://www.frogpondpottery.com Email: john@frogpondpottery.com
"The life so short, the craft so long to learn." Chaucer's translation of
Hippocrates, 5th cent. B.C.
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