Joyce Lee..........Jim Lee on fri 25 oct 96
RE Karen G.'s suggestion for a mamo glaze, Tom Gray has such a recipie
for highfire at tgraypots@atomic.net. If you can't access his home page,
let me know and I'll send the mamo recipie.
Joyce
Tom Buck on thu 11 feb 99
Mary:
The creamy white is not a glaze for C6ox; it is closer to a wash
(or slip). As you suspected the zinc oxide is high and may cause trouble.
The opaque white hue comes from willemite, Zn2SiO4, which becomes
tiny crystals (or not so tiny) as a separate material in the molten glass
that cools to become the glaze. (It is a zinc crystalline "glaze".)
So the glaze's performance will be linked to 1) the density of the
glaze slurry; best for dipping would be 1.53 to 1.57 grams per millilitre.
Over time, water would evaporate off and the density would rise, making
the glaze coat thicker. Also, this wash needs to be on a balanced C6 mix
to be most effective.
and 2) The firing cycle. Because the Creamy White is quite low on
silica, other fluxes will compete with the zinc oxide for the silica.
Depending on how the firing goes, what else is in the kiln, and how long
the soak is, you will get different results from this mix.
Can it be fixed? Revising the recipe may not provide you with what
you seek. So I suggest staying with the mix as is, but watching the slurry
density closely and advising all to use it only on top of other glazes you
are happy with. And try to get kiln loads that require a lengthy soak at
C6 (30-60 minutes). Good pots.
Tom Buck ) tel:
905-389-2339 & snailmail: 373 East 43rd St. Hamilton ON L8T 3E1 Canada
(westend Lake Ontario, province of Ontario, Canada).
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