Susan Wintrop on sun 13 oct 96
Many thanks for the interest in the turquoise lustre glaze. I am a glaze
recipe hound myself and love raku glazes that don't produce the expected
raku effects. Silver nitrate glazes are one of those anomalies. But it's a
tricky one because it can be unstable when fired and wash down the drain !
I hope this doesn't get too long winded but using this chemical needs a few
words.
Silver nitrate is poison and corrosive. In solution, if spilled, it stains
the surface a revolting liver colour forever. If splashed on hands or
skin...liver again for many weeks. Rehearsal for age spots.
Silver nitrate crystals can be ordered through a pharmacy or you can beg on
the graces of a chemistry department to distill you some in an experiment
dissolving sterling in nitric acid then diluting it in distilled water.
Crystals are the way to go.
Silver nitrate crystals are weighed by grams and added to distilled water.
The ratio is one gram to 10 mls of water. So 5 grams go into 50 mls. etc.
Store the dissolved solution in a coloured bottle and keep it out of light.
When measuring the solution to be added to your glaze WEAR RUBBER
GLOVES,CLOTHING YOU HATE and open the windows wide. This stuff doesn't smell
at all but it's powerful .
Add the needed amount to the MIXED and SIEVED glaze and stir carefully. It
will make the texture of the glaze peculiar at first, sort of curdled but
keep on stirring and it will smooth out. Wash the stirring implement
thoroughly especially if it's metal. This glaze is best painted on in three
smooth coats. Use a special brush for this glaze as it will be perm. stained
black.
When fired to cone O8 it becomes very soft and any material the piece comes
in contact with in the reduction bucket will mark it. I prepare my bucket
with a piece of cardboard set over newspapers . Lots of reduction but on a
platform.
When cool wash the piece carefully using no abrasives as it may scrub off
all the golden lustre.In time the piece will mellow even more and aquire
mother of pearl tones.
Here are two glazes that work well.
Silver Nitrate Glaze O6-O8
Gerstley 75
Neph. Sye. 20
EPK 5
Sil. Nit. 10 mls. ( that's one dissolved gram)
Fools Gold O6-O8 (less stable)
Frit 3110 50
Gerstley 20
EPK 8
Neph. Sye. 22
Tin Ox. 2
Rutile 2
Yelloe Ochre 2
Sil. Nit. 1.50 (or 7mls. of dissolved solution.)
Silver nitrate takes some testing and lots of care but it's a glorious
addition to your palete when you get it. Keep notes always.
Best wishes
Susan.
------------------------------------------------------------
Susan Wintrop
East West Pottery
Niagara-on-the-Lake, Ont.
wintrop@vaxxine.com
------------------------------------------------------------
| |
|
