Lily Krakowski on tue 22 oct 02
You better believe it. It may not depend on the supplier but on the source.
Mines, mine runs. Tom Buck once sent me analyses infor for different neph
sys. Wow. Or why Neph is the one non-clay material I buy in big bags==50
lb nowadays--that last me for several years.
But--I have not seen the book--color photography is not what it should be
yet. This Summer I painted a boat bright bright blinding green--photos,
best film, etc--sickly yellow...
deborah olson writes:
> Can different supplier's nepheline syenite affect the outcome of a glaze?
> I made weathered bronze perfectly the first time. The second time I made
> it with a new suppliers nepheline syenite it came out flat and matt.
>
> Also trying to make John and Ron's glazes they came out good but not
> the same colors as the pictures show. The other chemicals in the
> glazes are pretty basic. I basically am not getting the textured appearance.
>
> Thank you in advance.
>
> Deborah Olson
> Stolp Pottery
>
> ______________________________________________________________________________
> 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.
Lili Krakowski
P.O. Box #1
Constableville, N.Y.
(315) 942-5916/ 397-2389
Be of good courage....
deborah olson on tue 22 oct 02
Can different supplier's nepheline syenite affect the outcome of a =
glaze?
I made weathered bronze perfectly the first time. The second time I =
made
it with a new suppliers nepheline syenite it came out flat and matt.
Also trying to make John and Ron's glazes they came out good but not
the same colors as the pictures show. The other chemicals in the=20
glazes are pretty basic. I basically am not getting the textured =
appearance.
Thank you in advance.
Deborah Olson
Stolp Pottery
Steve Mills on wed 23 oct 02
The answer is a definite YES
As pottery suppliers our golden rule is *change nothing*. In the 22
years we've been in business we have always made strenuous efforts to
ensure that the only changes in our materials are natural seam changes,
about which we can do nothing. In the last 6 months we have had to
change OUR Nepheline Syenite as our source's suppliers minimum order
went up to 10,000 tonnes per annum!!! Our new supply is 4 to 5 percent
lower in silica. Not a lot you may say, but it can make a difference,
and how!!!
We have publicised the change in our new catalogue.
Steve
Bath
UK
In message , deborah olson writes
>Can different supplier's nepheline syenite affect the outcome of a =
>glaze?
>I made weathered bronze perfectly the first time. The second time I =
>made
>it with a new suppliers nepheline syenite it came out flat and matt.
>
>Also trying to make John and Ron's glazes they came out good but not
>the same colors as the pictures show. The other chemicals in the=20
>glazes are pretty basic. I basically am not getting the textured =
>appearance.
>
>Thank you in advance.
>
>Deborah Olson
>Stolp Pottery
--
Steve Mills
Bath
UK
Ron Roy on sun 27 oct 02
Neph Sy is sold according to mesh size - I always use 270. If the particle
size is smaller (bigger mesh #) then more melting and more sodium is
released into the glaze slop.
I have not seen any bad results from it over the years and it is used in
many clay bodies. This should be a material that is reliable - but watch
the mesh size.
RR
>Can different supplier's nepheline syenite affect the outcome of a glaze?
>I made weathered bronze perfectly the first time. The second time I made
>it with a new suppliers nepheline syenite it came out flat and matt.
>
>Also trying to make John and Ron's glazes they came out good but not
>the same colors as the pictures show. The other chemicals in the
>glazes are pretty basic. I basically am not getting the textured appearance.
>
>Thank you in advance.
>
>Deborah Olson
>Stolp Pottery
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
iandol on tue 7 jan 03
Dear Friends,
I think the answer to the question as to why Nepheline Syenite is such =
an excellent lower temperature Melting Flux is now apparent. There seems =
to be the potential for two processes to operate as temperature rises.
So the vitrification process should proceed well at temperatures near or =
below the 1100=B0Celsius (2012=B0F) mark, making it a very useful =
material for mid fire Clay and Glaze Aficionados. Those examples where =
there is a lower proportion of Al2O3 may melt at lower temperatures than =
this.
M. Cardew, "Pioneer Pottery" has interesting things to say about this =
material for those searching for a stable Bright Red Glaze using Iron =
oxides.
I think there are two things to watch for when selecting your Nepheline =
Syenite. The first is whether or not it has undergone some sort of =
refinement or beneficiation to remove the more undesirable Elements such =
as Iron, a necessity when selling high tonnages to the Whiteware =
industries as both a body flux and for glazes. The second would be the =
Na2O/K2O ratio. The Na2O value of the Nepheline and Albite components =
needs to be as high as possible but it must contain some K20 for one =
process to work.
Best regards to all,
Ivor Lewis, Redhill, South Australia
Jorge Nabel on thu 1 may 03
Clayarters, lots of recipes claim for Neph Sye. I cant get it here, and
importing it is not a possibility. So, how can I substitute ???I tried the
archives but no matches. Maybe this was already discussed, can you suggest
the subject???
Jorge en Buenos Aires, working on the workers day
Geoffrey Gaskell on fri 2 may 03
Jorge Nabel asks:
> Clayarters, lots of recipes claim for Neph Sye. I cant get it here, and
> importing it is not a possibility. So, how can I substitute ???
Hamer gives the chemical formula for Nepheline syenate (where the numbers I
put in parentheses = whole numbers; but the others represent subscripted
numbers) as:
K2O.(3)Na.2O.(4)Al2O3.(8)SiO2.
and describes it as "a useful substitute for the normal feldspars in bodies
and glazes because of its lower melting point."
The closest matching feldspar types in terms of chemical formula appear to
be Orthoclase and microcline (potash feldspars) with the formula:
K2O.Al2O3.(6)SiO2.
and Albite (soda feldspar) with the formula:
NaKO.Al2O3.(2)SiO2.
I would speculate that a prudent combination of these materials might make a
reasonable substitute for Nepheline syenate. Exactly what that prudent
combination would be is presently beyond my own level of knowledge, but it
does look like a reasonable "guestimate". OTOH I am quite prepared to stand
corrected in no uncertain terms, if I have inadvertently promoted the
production of some sort of high explosive.
Geoffrey Gaskell
June Perry on fri 2 may 03
It won't match the formula exactly, but you might get away with using a soda
spar if they are available.
Regards,
June Perry
http://www.angelfire.com/art2/shambhalapottery/index.html
Leland G. Hall on fri 2 may 03
Hello Jorge,
I have some recipes from a work shop which substitute Custer Feldspar for
Neph Sye. I have tried them and they work fine. These are Raku Glazes.
You know, the old 80/20 stuff. (GB/Neph Sye) I have no idea if this will
help you at your temps, or with your glazes. The Gurus need to weigh in on
this one for you. Also, I wonder, will the other spars do the trick like
Custer?
Best Regards
Leland Hall
Before The Wheel Enterprises
La Pine, OR, USA
Jorge wrote
"Clayarters, lots of recipes claim for Neph Sye. I cant get it here, and
importing it is not a possibility. So, how can I substitute ???I tried the
archives but no matches. Maybe this was already discussed, can you suggest
the subject???"
Jorge en Buenos Aires, working on the workers day
Tony Hansen on fri 2 may 03
I tried a rather fascinating exercise in
calculating a substitute. I put F4 feldspar
on one side (in INSIGHT) and fiddled with the
recipe on the other side and got about 77 Nepheline,
3 Wollastonite, 4 EPK and 16 Silica to create the
same chemistry. You cannot do it the other way.
To substitute for 50 nepheline you would then
recalculate the total so that there is
50 nepheline. That would be 50 Nepheline,
2 wollastonite, 2.5 EPK and 10.5 silica, a total
of 66.
That means you would remove 50 nepheline from
the recipe and put in 66 F4 feldspar and
remove 2 wollastonite, 2.5 EPK and
10.5 silica. Wierd. Whiting could be used instead
of wollastonite using a similar process.
An easier way is put the original recipe side by
side in a calculation program and drop the
nepheline and replace it with a feldspar in one
and then juggle the other ingredients to match the
chemistry back up.
> Hi Jorge....I live in Guatemala, and neph sye is not available here
> either....in my glazes, I use one feldspar substitute for the neph sye or
> any other feldspar that is called for. I buy the feldspar in 100 pound
> sacks at the toilet and sink factory in Guatemala City. It is from
> Guatemala, but they wil not give me any analysis so I don\'t know it\'s true
> make-up. I do know that it works very well in the cone 6 glazes that I use
> and also in the cone 6 porcelain body that I make.
> Find a source of feldspatho that is very fine mesh, and just use it as a
> substitute. You will have to do some testing, but I hope that you will be
> pleasantly surprised that it can work fine much of the time.
> My best to you,
========
Tony Hansen
Jonathan Kirkendall on fri 2 may 03
June,
Last night I was making up a glaze and ran out of neph sye - I hoped that I
could sub. soda spar, but what I read in Hamer and Hamer was that the
feldspar most closely matching neph sye was potash, that while soda spar
melted at the same temp, it could have a very different color response.
Jonathan in DC
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of June Perry
Sent: Friday, May 02, 2003 8:42 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Nepheline syenite
It won't match the formula exactly, but you might get away with using a soda
spar if they are available.
Regards,
June Perry
http://www.angelfire.com/art2/shambhalapottery/index.html
____________________________________________________________________________
__
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.
Ron Collins on fri 2 may 03
Hi Jorge....I live in Guatemala, and neph sye is not available here
either....in my glazes, I use one feldspar substitute for the neph sye or
any other feldspar that is called for. I buy the feldspar in 100 pound
sacks at the toilet and sink factory in Guatemala City. It is from
Guatemala, but they wil not give me any analysis so I don't know it's true
make-up. I do know that it works very well in the cone 6 glazes that I use
and also in the cone 6 porcelain body that I make.
Find a source of feldspatho that is very fine mesh, and just use it as a
substitute. You will have to do some testing, but I hope that you will be
pleasantly surprised that it can work fine much of the time.
My best to you,
Melinda Collins, Antigua, Guatemala
Ron Roy on wed 7 may 03
Hi Jonathan,
The reason Hamer said potash spar is because they have more KNaO than the
soda spars - but even the potash spars don't have enough. It would not be a
good idea to mix up a whole batch subbing any spar for Neph Sy - the
chances are slim that you would get the same looking glaze.
The question could be - how is Neph Sy different from the feldspars.
If we look at the analysis of some of the typical spars and compare then
with Neph Sy we see -
1. Neph Sy has less SiO2 and more Al2O3
2. More KNaO - especially more NaO2 (sodium)
This means it will melt at a lower temperature and if you look at melt
buttons that is confirmed.
At cone 6 the Neph Sy is well melted and the spars are not.
A side note - because Neph Sy has less SiO2 and more Al2O3 and Na2O it
makes an ideal material for making Shino glazes.
If we compare G200 and Neph Sy on a molecular basis - as if they are glazes
we see - with the fluxes in unity (adding to 1.0)
The Neph Sy has more sodium and less SiO2 and about the same Al2O3.
So it would seem - from a melting stand point it would be a better material
for making cone 6 glazes - especially clay matte glazes because they like
less silica.
The main problem is - unless there is enough clay in the glaze the sodium
in the Neph Sy leaches out and deflocculates the glaze and it settles out
quickly and can be hard to stir up. The soluble sodium can also be a
problem because it migrates to the surface as the glaze dries and over
fluxes locally.
So here is a glaze I just made up to illustrate the problem and how I would
fix it to avoid the settling problem (I have not fired it - I have no idea
what it will look like - well let me guess - Clear, shiny, durable - maybe
runs a bit when on thicker. If anyone fires it I would be interested to
know. The problem with it will be settling in the bucket - probably hard
pan on the bottom of the bucket.
Neph Sy - 25.0
Whiting - 25.0
Frit 3124 - 10.0
Talc - 5.0
EPK - 5.0
Silica - 30
Total - 100.0
Ratio - 10.64 (SiO2 to Al2O3)
Expansion - 434.41
So how to fix it - take out some or all of the Neph Sy and replace with
spar. Take out Frit 3124 because it has Al2O3 in it and replace with 3134
which has none so I can get more clay in the glaze - use ball clay instead
of Kaolin because ball clay has less alumina in it and so I can use more -
and - it works better with bentonite as a suspender than Kaolin if I need
it. I will also use some Frit 3110 because I will need extra KNaO which the
replacement spar will not have. Frit 3110 is ideal in this case because it
has only a small amount of alumina and boron.
G200 - 22.5
F3134 - 14.0
F3110 - 4.0
Whiting - 10.5
Talc - 5.0
Bell Dark - 20.0
Silica - 24.0
Total - 100.0
Ratio - 10.80
Expansion - 437.84
There is more iron and titanium because of the ball clay but I don't think
anyone will notice it.
A note about Frit 3110 - it will leach sodium into glazes the same way Neph
Sy does.
Again - this job is made relatively easy using a glaze calculator - Imagine
trying to do this with line blending materials.
I have tried to keep this a reasonable length - if there are questions I
will try to answer them.
RR
>Last night I was making up a glaze and ran out of neph sye - I hoped that I
>could sub. soda spar, but what I read in Hamer and Hamer was that the
>feldspar most closely matching neph sye was potash, that while soda spar
>melted at the same temp, it could have a very different color response.
>
>Jonathan in DC
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Joe Coniglio on fri 23 may 03
jconiglio@ssaris.com
Joe Coniglio
----
Hi I see this ingredient in many glazes like "shinos".
Any common name to it?
What is it?
Where does it come from? Geologically, Chemically and Geographically?? :-)
Safe to use?
Thanks!!!!!
------
Have a great Memorial Day weekend.
JoeC
Tony Hansen on sat 24 may 03
Try going here:
http://www.digitalfire.ab.ca/cermat/ceramicmaterials/material.php?goto=Nepheline%20Syenite
-------8<--------
jconiglio@ssaris.com
Hi I see this ingredient in many glazes like \"shinos\".
Any common name to it
What is it
Where does it come from? Geologically, Chemically and Geographically?? :-)
Safe to use?
--------
Tony Hansen, Digitalfire Corp.
Tom Buck on fri 13 jan 06
SS:
Main sources of Neph Sy are 1st Ontario Canada; 2nd South Africa
(I have analysis of each). Neph Sy is a mix of two separate minerals that
then became fossilized (became rock).
A standard feldspar has an approximate Seger Unity Forumla of 1
mole flux oxides to 1 mole alumina to 6 moles silica, 1:1:6, but neph sy's
Seger is 1:1:4 -- so one does have to adjust for the low silica if
converting from Neph Sy to say Custer or G-200 potspar.
If going from Neph Sy to Custer, one has to remove silica/flint/quartz
from the rest of the receipe's ingredients (somehow). If going from
Custer to Neph Sy, one adds flint/silica/quartz.
good pots peace Tom.
Tom Buck ) -- primary address.
"alias" or secondary address.
tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada
Steve Slatin on sun 15 jan 06
Eleanora --
I have a nepheline syenite glaze that doesn't settle out -- in fact, it's
unusually easy to stir up. And it's 5/12 N-S, so it's a pretty heavy
dose.
-- Steve Slatin
Eleanora Eden wrote: I have always suspected that neph sy is a major player in making the
glaze stick unyieldingly to the bottom of the glaze bucket. Any
opinions on that?
Eleanora
Steve Slatin --
And I've seen it all, I've seen it all
Through the yellow windows of the evening train...
---------------------------------
Yahoo! Photos
Ring in the New Year with Photo Calendars. Add photos, events, holidays, whatever.
Eleanora Eden on sun 15 jan 06
I have always suspected that neph sy is a major player in making the
glaze stick unyieldingly to the bottom of the glaze bucket. Any
opinions on that?
Eleanora
eleanoraeden.com
Snail Scott on mon 16 jan 06
At 02:01 PM 1/15/2006 -0500, you wrote:
>I have always suspected that neph sy is a major player in making the
>glaze stick unyieldingly to the bottom of the glaze bucket. Any
>opinions on that?
Yep, neph sy loves to settle. When mixing up
a glaze in quantity, I try to never put the
neph sy in 'til late, to keep the stuff out
of the bottom corners of the bucket. I also
add some bentonite.
-Snail
Bob Hanlin on tue 17 jan 06
I've had a bit of trouble with the stuff too. I find that a bit of epson salt in the water before the neph...helps.
Bob
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