Anthony Allison on tue 24 nov 98
Hi Clay People,
Thanks to an alfred recipe kindly provided to me by Kurt Wild, I have come
up with a super fantastic green glaze which I would like to share with you
all. The base glaze is an old spodumene glaze. Two firings ago, I got quite
a pleasant surprise. I was going for a subtle grey green. But the result was
a thrilling beautiful lively warm green which I simply could not believe. My
last firing confirmed its beauty by giving me another unexpected surprise.
(some nice brown pots). Like all good things, alas it is a spirited beauty,
the kind that can make your day or kick you in the ____. But to get that
green again......!!!
Cone 10 reduction
22% flint
43% spodumene
17% kaolin (deviation from Alfred recipe which calls for 9 percent calcined
kaolin and 8% regular kaolin)
add
1/2% chrome
1/8% rutile
1/8% nickel nitrate
My sucessful trial was applied rather thick.
Good luck!
Tony
PS. This base glaze gives lively blues as well.
Louis Katz on wed 25 nov 98
Looked up Nickel Nitrate in my Handbook of Chemestry and physics just to be
sure it was soluble. It is. It is also a
Carcinogen(http://www.epa.gov/envirofw/html/emci/chemref/14216752.html)
I suspect that some of the variability is do to using a soluble form of nickel.
This is not a material I would be dipping my hands in. I would also be wary of
handling the dry glazed pots loading the kiln.
I supect that somewill point out that nickels might contain more nickel than
this glaze, but nickels are not so water soluble.
FYI
Conversion from Nickel Nitrate to Nickel Carbonate
1/8%= 0.125%
(.125%/ Molecular weight of Nickel Nitrate )*Molecular Weight of Nickel
Carbonate)
(.125 % Nickel Nitrate*290grams/mol Nickel Nitrate) *118.72 grams per mol
Nickel Carbonate= 0.051 percent or about 1/20th of a percent Nickel Carbonate.
My suspicion is that because of a lack of good dispersion it will take a bit
more than this, but.... It may not work the same at all.
Louis
Anthony Allison wrote:
> Cone 10 reduction
>
> 22% flint
> 43% spodumene
> 17% kaolin (deviation from Alfred recipe which calls for 9 percent calcined
> kaolin and 8% regular kaolin)
> add
>
> 1/2% chrome
> 1/8% rutile
> 1/8% nickel nitrate
>
>
--
Louis Katz
lkatz@falcon.tamucc.edu
NCECA Director At Large
Texas A&M-CC Division of Visual and Performing Arts Webmaster (512) 994-5987
Bill Amsterlaw on sat 28 nov 98
Hi Tony Allison, Louis Katz, & Clayart:
Louis Katz submitted a calculation for substituting nickel carbonate for
nickel nitrate in Tony Allison's "Green of the Sirens" glaze. I follow the
logic of Louis' calculations, but I believe he used an incorrect figure for
the molecular weight of nickel nitrate. Also, I think the the calculation
cannot account for the extreme volatility of nickel nitrate.
Atomic weights:
Ni 58.71
N 14.008
O 16
C 12.011
Nickel carbonate, NiCO3, has a molecular weight of 118.72
Nickel nitrate, Ni(NO3)2, has a molecular weight of 182.726, rather than the
figure of "290" used by Louis.
I would figure the substitution as follows:
Let C = amount of NiCO3
N = amount of Ni(NO3)2
mols of Ni contained in C = C / 118.72
mols of Ni contained in N = N / 182.726
C / 118.72 = N / 182.726
C = (118.72 / 182.726) * N
C = 0.65 * N
The original recipe called for 0.125% nickel nitrate.
The amount of nickel carbonate containing the same amount of nickel would be
0.65 * 0.125% = 0.08% (rather than Louis' figure of 0.05%).
At any rate, it seems unlikely to me that nickel is contributing in any
significant way to this glaze because I found in the description of physical
properties of nickel nitrate that IT BOILS AT 137 C. I would guess that the
small amount of nickel nitrate called for in the original recipe would have
completely volatilized long before the glaze began to sinter. I would test
the glaze with amounts of nickel carbonate ranging from 0 to 0.2% to see
what effect this small amount of nickel might have, if any.
Working on this problem gave me an appreciation of the complexity of
calculating a substitution. (Being dumb in math and chemistry were
contributing factors.) When I first thought about it, I was confused by how
you would take into account the loss on ignition of BOTH compounds, assuming
that nickel nitrate would become nickel oxide and nickel carbonate would
become nickel oxide. Then I realized that by looking at the molecular
weights you could calculate a ratio that gave the equivalent weight of
nickel for the two compounds; the lost, non-nickel part of each molecule
didn't matter ... which should make most substitution calculations pretty
straightforward. But then I learned that nickel nitrate is highly volatile -
ie, the nickel itself is lost on ignition! Then it got very complicated
because I realized that there would be so many variables that would
determine how much (if any) nickel would remain that there really is no way
to calculate a substitution.
- Bill Amsterlaw (wamster@slic.com)
Plattsburgh, NY
--
Tony Allison submitted the following glaze:
Cone 10 reduction
flint 22
spodumene 43
kaolin 17
add:
chrome 0.5
rutile 0.125
nickel nitrate 0.125
Louis Katz wrote:
<<
Looked up Nickel Nitrate in my Handbook of Chemestry and physics just to be
sure it was soluble. It is. It is also a carcinogen
(http://www.epa.gov/envirofw/html/emci/chemref/14216752.html)
I suspect that some of the variability is due to using a soluble form of
nickel. This is not a material I would be dipping my hands in. I would also
be wary of handling the dry glazed pots loading the kiln. I supect that some
will point out that nickels might contain more nickel than this glaze, but
nickels are not so water soluble.
FYI
Conversion from Nickel Nitrate to Nickel Carbonate
1/8%= 0.125%
(.125%/ Molecular weight of Nickel Nitrate )*Molecular Weight of Nickel
Carbonate)
(.125 % Nickel Nitrate*290grams/mol Nickel Nitrate) *118.72 grams per mol
Nickel Carbonate= 0.051 percent or about 1/20th of a percent Nickel
Carbonate.
My suspicion is that because of a lack of good dispersion it will take a bit
more than this, but.... It may not work the same at all.
>>
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