Chuck Wagoner on fri 27 jul 07
Great information basin of Clayart,
Could someone confirm for me that NC-4 feldspar is equal to G-200? I have
two bags of it and would like to use it.
We can dig up a lot of clay here in Indiana, but no feldspar in my back
yard.
Thank you,
Chuck, in Rockville where I am going to go play some tennis on clay today,
if it does not rain, although we need the rain so I'll be happy which ever
way.
David Beumee on fri 27 jul 07
Chuck,
I can't confirm that NC-4 is equal to G-200. My fusion button tests reveal that
NC-4 is almost an identical melt to Kona F-4. Both NC-4 and F-4 are sodium based spars, and have a stronger melt than G-200, a potash based spar.
David Beumee
Lafayette, CO
www.davidbeumee.com
-------------- Original message ----------------------
From: Chuck Wagoner
>
> Great information basin of Clayart,
>
> Could someone confirm for me that NC-4 feldspar is equal to G-200? I have
> two bags of it and would like to use it.
>
> We can dig up a lot of clay here in Indiana, but no feldspar in my back
> yard.
>
> Thank you,
>
> Chuck, in Rockville where I am going to go play some tennis on clay today,
> if it does not rain, although we need the rain so I'll be happy which ever
> way.
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Ted Neal on fri 27 jul 07
Chuck
NC-4 is classified as a soda feldspar based on the relative proportions of sodium
over potassium.
G-200 is a potash feldspar based on an almost opposite content of the two main flux materials.
They can be considered very similar in action, (enough so that Potassium and Sodium are often
listed together with the chemical symbol KNaO in glaze calc) but they are not identical.
I would run a little test before commiting to a direct replacement.
Ted Neal
Ball State University
On Fri, 27 Jul 2007 09:59:22 -0400, Chuck Wagoner wrote:
>Great information basin of Clayart,
>
>Could someone confirm for me that NC-4 feldspar is equal to G-200? I have
>two bags of it and would like to use it.
>
>We can dig up a lot of clay here in Indiana, but no feldspar in my back
>yard.
>
>Thank you,
>
>Chuck, in Rockville where I am going to go play some tennis on clay today,
>if it does not rain, although we need the rain so I'll be happy which ever
>way.
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Gary Wagoner on fri 27 jul 07
Nope. NC-4 is a match for Kona F-4, a soda spar. G-200 is a potash spar.
On Jul 27, 2007, at 8:59 AM, Chuck Wagoner wrote:
> Great information basin of Clayart,
>
> Could someone confirm for me that NC-4 feldspar is equal to G-200?
> I have
> two bags of it and would like to use it.
>
> We can dig up a lot of clay here in Indiana, but no feldspar in my
> back
> yard.
>
> Thank you,
>
> Chuck, in Rockville where I am going to go play some tennis on clay
> today,
> if it does not rain, although we need the rain so I'll be happy
> which ever
> way.
>
> ______________________________________________________________________
> ________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
Chuck Wagoner on fri 27 jul 07
Thanks Gary!
The company I buy materials from gave me NC-4 when I asked for G-200. =
They
do not carry G-200 and I guess the "guy in back" just substituted =
feldspar.=20
Good to see someone spelling "Wagoner" with one "g" and one "o"
Chuck
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Nope. NC-4 is a match for Kona F-4, a soda spar. G-200 is a potash spar.
On Jul 27, 2007, at 8:59 AM, Chuck Wagoner wrote:
claystevslat on sun 29 jul 07
Chuck --
They are close, but not identical.
Digital fire gives NC-4 as
CaO 1.400
K2O 4.100
MgO 0.050
Na2O 6.800
Al2O3 18.850
SiO2 68.150
Fe2O3 0.070
And G-200 as
Fe2O3 0.080
SiO2 66.300
Al2O3 18.500
Na2O 3.040
K2O 10.750
MgO 0.050
CaO 0.810
The biggest difference is in the sodium/potassium mix.
G-200 is more potash intensive, NC-4 relies more on
sodium.
My (very crude) rule of thumb on this kind of sub is
if the feldspar makes up less than 1/5 of the glaze
and is more or less what I'm looking for, I do a 1
for 1 sub first and then fix it if I don't like the
outcome on a test. If it's more than that, I will
try to correct up-front.
Remember all feldspars are subject to minor changes in
composition. Except for the K/Na, I wouldn't expect
the differences to be significant in most glazes ...
but the Li-rich glazes I've been experimenting with
of late are all 'tippy' and a change of 1/2 of a percent
in anything -- even silica -- will change the glaze
appearance (and, possibly, durability).
Good luck -- I'd be interested to know how things turn
out -- Steve Slatin
--- In clayart@yahoogroups.com, Chuck Wagoner wrote:
>
> Great information basin of Clayart,
>
> Could someone confirm for me that NC-4 feldspar is equal to G-200?
I have
> two bags of it and would like to use it.
>
> We can dig up a lot of clay here in Indiana, but no feldspar in my
back
> yard.
>
> Thank you,
>
> Chuck
Chuck Wagoner on sun 29 jul 07
Thanks to everyone that gave me such good responses on and off list.
I am just getting some G-200 from another supplier. The company that I was
getting NC-4 from is no longer under the impression that NC-4 and G-200 are
close enough to substitute. I had not used it as a sub yet, just checking.
This is just another reason that Clayart is so great for a potter in the
woods of Indiana (like me) or anywhere. Nothing like knowing I can tap into
the best clay minds of the world. Thanks again....Chuck Wagoner
======================================================================
Chuck --
They are close, but not identical.
Good luck -- I'd be interested to know how things turn
out -- Steve Slatin
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