Roeder on thu 26 sep 96
Hello all,
I am having a problem with a glaze. It is a cone 6 oxidation glaze, "charcoal"
variation of Pinnell Strontium Matt Glaze. I am trying to achieve a (cobalt)bla
variation, rather than the greenish black that the Charcoal version produces.
I took colorants from a favorite black glaze recipe and used those percentages i
Strontium Matt base. The results were black, but very dry and underfired lookin
fire this glaze to cone 7, BTW)
Could the colorants I added have a refractory effect, and if so, how do I correc
problem?
Here's the base glaze:
Lithium Carb........1.0
Strontium Carb.....20.0
Nepheline Syenite..60.0
Ball Clay..........10.0 (I use OM4)
Flint.............. 9.0 (I use 325 mesh)
For Charcoal: Manganese Dioxide....2.0
Copper Carbonate.....5.0
For my black I added these colorants, rather than those above:
Chrome.......1.14
Cobalt Carb 4.55
Red Iron Ox..3.41
Any ideas? I'd appreciate help on this one.
Thanks.
Candice Roeder
living "in the sticks" in Michigan
William Amsterlaw on fri 27 sep 96
For Candice Roeder:
Last March, Dave Kuilema asked the same question about the same glaze and Pete
Pinnell responded:
>>
------------------------------
Date: Mon, 25 Mar 1996 14:26:10 EST
From: peter pinnell
Subject: Re: glaze problems
As a quick-and-dirty solution for slightly underfired cone 6 glazes, add 5 to
10% gerstley borate. With all the lithium carb.in this, you will also want to
add a strong flocculant. Try adding 1/4 to 1/2% epsom salts, or muriatic acid
(usually 1-2 tablespoons per 10,000 grams dry weight of glaze, but a glaze
like this may require more in the neighborhood of 1/4 cup per 10,00 grams).
Pete Pinnell
On Thu, 21 Mar 1996, Dave Kuilema wrote:
>>
----------------------------Original message----------------------------
Is there any way to make this glaze more fluid? It is too dry when I add 6%
of mason stain titanium yellow. The glaze works fine with other oxides at
cone 6 or 7 Strontium Matt Lith. carb 4 Strontium carb 28 Neph Sy 60
Ball Clay 9 Bentonite 1 Flint 9.
<<
<<
Karen Gringhuis on thu 3 oct 96
You should have kept the manganese. Try coloring w/ Chrome 1%/ Red iron ox 3%
Matt. At C/9-10, one even gets a blue edge where thin. If it's still too dry,
Matt also incl. note to use 80 mesh granular Mn instead of MnO2 to get silvery
specks. TEST TEST TEST. Regards, Karen Gringhuis
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