C J TRIPP on fri 2 jun 00
Cindy Strnad posted some results from her glaze tests last week.
Just goes to show you that everyone's tests turn out differently; I tried
John H's Xavier's Warm Jade Green (had to sub 3134 for 3124) and it turned
out yellowish pea green. Not nice at all. Live and learn.
I have a hankering to try Gibby's Wild Rose Tenmoku and the other glaze
Cindy posted but they both have lithium carb in them and that makes me
nervous. Call me Chicken but twice in my life I have lived with people who
had manic depression and the changes lithium brought to them were
unbelievable. It's very powerful stuff - in people and on pots. Any
thoughts to ease my fears or increase them?
Thanks.
I'm pulling a late night here as I wait and wait and wait for ^6 to fall and
I can fire down my kiln that's being badly controlled by my nearly new but
malfunctioning controller. It was supposed to reach top temp and go to soak
hours ago. This load has to finish as it's the last before summer shut
down. All the summer's visiting gifts are in it. Now, wasn't that silly to
put all my eggs/pots in one basket/kiln? Full Clayart chorus of YES!
Carol
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John Hesselberth on sat 3 jun 00
C J TRIPP wrote:
>Cindy Strnad posted some results from her glaze tests last week.
>Just goes to show you that everyone's tests turn out differently; I tried
>John H's Xavier's Warm Jade Green (had to sub 3134 for 3124) and it turned
>out yellowish pea green. Not nice at all. Live and learn.
>I have a hankering to try Gibby's Wild Rose Tenmoku and the other glaze
>Cindy posted but they both have lithium carb in them and that makes me
>nervous. Call me Chicken but twice in my life I have lived with people who
>had manic depression and the changes lithium brought to them were
>unbelievable. It's very powerful stuff - in people and on pots. Any
>thoughts to ease my fears or increase them?
Hi Carol,
It's not surprising at all that you got a different glaze when you
substituted 3134 for 3124. Those are quite different frits and should
not be considered interchangeable. By the way Xavier's Warm Jade Green
is not my glaze. It is from Val Cushings's Handbook and was brought to
the list by Heidi Haugen. I only got involved when Heidi shared her
testing results; I then tested it myself with 3 levels of copper
carbonate and confirmed Heidi's results--it is a very stable
copper-containing glaze.
On your lithium question, I would make a couple comments. The levels of
lithium given for manic depression are quite high--near the toxic level.
Therefore, I suppose it is conceivable that if you had a really badly
leaching glaze you might put someone who was on that medication over the
edge of toxicity. The amount that would leach from a stable glaze is
many, many times less. For example Diane Woloshyn tested two lithium
containing glazes: Gibby's Wild Rose/Kaki leached 7.32 mg/l and Falls
Creek Shino leached less than the detectable limit. Diane stated, in her
message to the list last September, that she had decided not to use
Gibby's on food surfaces. I think that is a good decision. It probably
wouldn't cause any harm, but why take the chance when much more stable
glazes can be made? She, of course, does use Fall Creek Shino on food
surfaces and will continue to do so. This was a case where testing
helped Diane make a decision that will give her a lot more confidence
about the quality of the pots she is selling.
John Hesselberth
Frog Pond Pottery
P.O. Box 88
Pocopson, PA 19366 USA
EMail: john@frogpondpottery.com web site: http://www.frogpondpottery.com
"Pots, like other forms of art, are human expressions: pleasure, pain or
indifference before them depends upon their natures, and their natures
are inevitably projections of the minds of their creators." Bernard
Leach, A Potter's Book.
thansen@DIGITALFIRE.COM on mon 5 jun 00
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> It's not surprising at all that you got a different glaze when you
> substituted 3134 for 3124. Those are quite different frits and should
> not be considered interchangeable.
These two frits are actually identical except that frit 3124 contains
a bunch of alumina and 3134 is alumina-free. Substituting
3134 for 3124 would remove alot of alumina from the glaze making
it a lot more runny and a lot more prone to crystalization. If iron
were present, for example, yellowish crystal formation could turn a
glaze to a totally different color.
--
====================================================
T o n y H a n s e n thansen@digitalfire.com
http://digitalfire.com Calculation/Database Software for Ceramic Industry
http://ceramicsearch.com Search engine for the Ceramic Industry
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Ron Roy on mon 5 jun 00
As you all know by now - I do not like lithiun carb very much at all. My
main complaint is the really weird fit problems it can produce. I am going
to say in amounts over 2%. I have seen shivering and crazing on the same
pot.
The reason this is so - of all the carbonates - lithium is the most
soluble. That means some of it moves around in the body carried by water
and of course affects melt where it ends up.
The other problem - glazes with very low expansion can be made with Lithium
and Magnesium - if you are into that make sure you do a lot of fit testing
- nothing like flakes of razor sharp glaze in a pot to scare the pants off
your customers.
RR
>It's not surprising at all that you got a different glaze when you
>substituted 3134 for 3124. Those are quite different frits and should
>not be considered interchangeable. By the way Xavier's Warm Jade Green
>is not my glaze. It is from Val Cushings's Handbook and was brought to
>the list by Heidi Haugen. I only got involved when Heidi shared her
>testing results; I then tested it myself with 3 levels of copper
>carbonate and confirmed Heidi's results--it is a very stable
>copper-containing glaze.
>
>On your lithium question, I would make a couple comments. The levels of
>lithium given for manic depression are quite high--near the toxic level.
>Therefore, I suppose it is conceivable that if you had a really badly
>leaching glaze you might put someone who was on that medication over the
>edge of toxicity. The amount that would leach from a stable glaze is
>many, many times less. For example Diane Woloshyn tested two lithium
>containing glazes: Gibby's Wild Rose/Kaki leached 7.32 mg/l and Falls
>Creek Shino leached less than the detectable limit. Diane stated, in her
>message to the list last September, that she had decided not to use
>Gibby's on food surfaces. I think that is a good decision. It probably
>wouldn't cause any harm, but why take the chance when much more stable
>glazes can be made? She, of course, does use Fall Creek Shino on food
>surfaces and will continue to do so. This was a case where testing
>helped Diane make a decision that will give her a lot more confidence
>about the quality of the pots she is selling.
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
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