Martin Howard on tue 28 sep 99
Following the kind release of the content of a certain photocopier
developer as
Copper Oxide CuO = 2-4% Weight
Zinc Oxide ZnO = 17-21%
Iron Oxide Fe2O3 = 66-69%
Nickel Metal Ni = 7-11%
First I got rid of the magnetic property by heating it in the kiln up to
1140 degrees centigrade.
I then tested it as percentage additions to my normal cone 02-1 clear
glaze of
20% montmorillonite (cat litter), 20% granite dust, 60% standard borax
frit.
At low percentages, 1-8, it just gives an increasing dark mottling on a
creamy background.
At 10 and 12 percent it produces a mottled olive greeny brown, verging
into khaki. Not very interesting or bright, but it could be used in
combination with others.
Certainly the Zinc is causing some opacity. I tested on background
vertical tiles with white slip on one side and my normal Valentines
standard red on the other. Both sides showed a similar colour.
It is what one might expect with those Zinc and Nickel contents. It may
be brighter if used with another clear glaze or with other oxide
additions. My basic glaze has a lot of other elements within it, so this
test is not really scientific. I will try it again with a bought, purer
glaze.
But I think it is worth risking a small bucket of it, 2500 gms, and see
how it goes.
Some people might love it.
At least I will do a bowl and mug and pass them to the firm concerned,
with thanks for their co-operation.
Are other potters doing this kind of testing or waste products? The
links made with other firms could well be of value financially or
otherwise to all concerned, but the main reason for such testing is
really environmental.
Martin Howard
Webbs Cottage Pottery and Press
Woolpits Road, Great Saling
BRAINTREE
Essex CM7 5DZ
01371 850 423
araneajo@gn.apc.org
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