Lili Krakowski on sat 6 oct 07
Oh dear, Jackie, oh dear!
People will tell you I am a total horror on this, and I am sorry.
You are buying premixed glazes figured out and calculated etc by specialists
who really know their stuff.
THEY know that two factors (at least) affect glaze color. The composition
of the glaze, and the added colorants. (A third factor would be the firing
process)
My guess would be that the grass green glaze contains some chrome, some
rutile, a lot of calcium, some boron...maybe magnesium.
My guess is that sea green would have copper, a smidge of cobalt, a soupcon
of tin...maybe a hint of manganese...
Boron? Strontium? Perhaps.
Do you see where I am going with this? You wanted to buy mayonnaise and you
bought hollandaise...Maybe.
And I assume you do not have glaze raw materials to begin with.
Suggestion: IF the glaze is listed as food safe use it on the INSIDE of
jars and pitchers.
Experiment using it in double application with a dark glaze.... blue or
black. Remember that double application can cause the glazes to run, so put
a little patty of clay beneath the test tile...
Put it on a shelf with the test tile attached to it--and some day someone
will offer you her eyeteeth to have mugs that color.
Welcome to the club!
Lili Krakowski
Be of good courage
Kathy Forer on sun 7 oct 07
Lili wrote:
>Experiment using it in double application with a dark glaze.... blue or black. Remember that double application can cause the glazes to run, so put a little patty of clay beneath the test tile...
>
>Put it on a shelf with the test tile attached to it--and some day someone will offer you her eyeteeth to have mugs that color.
I took a ceramics class at the local county park. The instructor Brian Quincannon gave us an excercise. We each chose one glaze and then made twenty different glazes on the mugs, double or triple layering with the eight other glazes.
Black and blue turned into a really nice, rich but snowy brown. It was great fun and very good learning.
Kathy
Ron Roy on mon 8 oct 07
For someone to say a glaze is safe - by law it must not leach certain
amounts of lead and cadmium - that is all that is covered in North America.
However - there are many glazes that are advertised as food safe that are
ridiculously unstable and will leach heavy metals into food and change
colour as well.
I would not assume any commercial glazes are stable enough to use with food
until I had them tested.
If I had to use them without testing I'd use clear or white glazes as liners.
RR
>Suggestion: IF the glaze is listed as food safe use it on the INSIDE of
>jars and pitchers.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
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