Arnolds Home Improvements on thu 7 sep 00
Thanks to all who have responded so far. As I said I am new to pottery and
to the clay art list, so I will make some mistakes at both until I learn,
but I will learn! Because I am a 50 year old building contractor that has
fallen in love with clay.
I understand now if you have a question about a recipe post it.(duh on my
part) so here is the one I use.
epk 26
frit3134 43
custer feldspar 26
silica 15
rutile 4
cobalt oxide 2
I ran one test with the glaze thick it came out a cloudy blue, next test I
thinned the glaze until it would pass the dry finger test, this is when I
get the green. I tried double dipping some pots with the glaze thinnned. I
had to grind kiln shelves the next day! (by the way I own a dremmel and an
angle grinder, the angle grinder works best)
I screen my glaze twice with a100 mesh screen.
If I add more cobalt will this be food safe?
I do not know the iron content of my clay, I use standards #153
Again I would like to thank all who responded at least I don't feel so all
alone now.
If I need to post more information please let me know . I think this will
be a beautiful glaze if all the bugs get worked out.
Gene Arnold
mudduck@advi.net
Paul Taylor on fri 8 sep 00
Dear Arnold
There is nothing I can see that is wrong with this glaze.
But titanium matt glazes ( rutile ) have particular firing cycles the
titanium sets up nuclei around which crystals grow I am not exactly sure of
the exact science but If the glaze is too thin there is no three dimensional
space for growth and if the kiln is fired too high the crystallization will
not work and too quick a cooling at certain temps will also
cause too much clarity in the glaze .
Of course some times the opposite happens to these glazes the extra alumina
in the glaze body layer will pre mote opacity where the glaze is thin and
clarity where the glaze is thick.
You do not have to adjust your firing by removing or adding more rutile
you can change the amount of opacity . Do not over do it, these glazes can
pin hole badly. I suspect not helped by quick cooling and/or carbon trapping
- but sill a mystery to me.
I do not think a bit more or less cobalt will poison any body the glaze is
lead free.
So some testing: looking for the optimum thickness of the glaze use a
feeler gage - the right amount of rutile and the right amount of cobalt for
your firing.
This glaze will also probably give a Chun effect to augment the blue
and/or the opacity this is an optical effect that is also affected by
temperature and cooling rates . But I only mention this in case you changes
to the formula do not bring the expected results.
Any body using these glazes will need an even firing kiln and an attention
to detail. Fortunately this is easier in an electric kiln where rutile
glazes can look their best.
-- Regards Paul Taylor.
Westport Pottery, Liscarney, County Mayo. Ireland.
http://www.anu.ie/westportpottery/
> From: Arnolds Home Improvements
> Reply-To: Ceramic Arts Discussion List
> Date: Thu, 7 Sep 2000 18:53:34 -0400
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: saffire blue recipe
>
> Thanks to all who have responded so far. As I said I am new to pottery and
> to the clay art list, so I will make some mistakes at both until I learn,
> but I will learn! Because I am a 50 year old building contractor that has
> fallen in love with clay.
> I understand now if you have a question about a recipe post it.(duh on my
> part) so here is the one I use.
> epk 26
> frit3134 43
> custer feldspar 26
> silica 15
> rutile 4
> cobalt oxide 2
>
> I ran one test with the glaze thick it came out a cloudy blue, next test I
> thinned the glaze until it would pass the dry finger test, this is when I
> get the green. I tried double dipping some pots with the glaze thinnned. I
> had to grind kiln shelves the next day! (by the way I own a dremmel and an
> angle grinder, the angle grinder works best)
> I screen my glaze twice with a100 mesh screen.
> If I add more cobalt will this be food safe?
> I do not know the iron content of my clay, I use standards #153
> Again I would like to thank all who responded at least I don't feel so all
> alone now.
> If I need to post more information please let me know . I think this will
> be a beautiful glaze if all the bugs get worked out.
>
> Gene Arnold
> mudduck@advi.net
>
> ______________________________________________________________________________
> 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.
John Hesselberth on fri 8 sep 00
Arnolds Home Improvements wrote:
>If I add more cobalt will this be food safe?
Hi Gene,
I could still be food safe, but the real answer to this is that no one
knows. You will have to have the glaze tested to see how much it leaches
at a higher level of cobalt. You can find instructions on how to do this
on my web site at:
http://www.frogpondpottery.com/glazetest.html
The glaze has plenty of silica and alumina--so much that it may not be
melting real well at cone 6. It also has more sodium/potassium than one
might like to see in a stable glaze. All that said,it has been tested by
Diane Woloshyn for leaching in its current form (2% cobalt oxide) and it
did very well. You can see the results of that testing on my web site
(URL below)--Diane shared the results with us some time ago and I publish
those results when the person who tests gives me permission to do so.
John Hesselberth
Frog Pond Pottery
P.O. Box 88
Pocopson, PA 19366 USA
EMail: john@frogpondpottery.com web site: http://www.frogpondpottery.com
"It is, perhaps, still necessary to say that the very best glazes cannot
conceal badly shaped pots..." David Green, Pottery Glazes
Sharon31 on fri 8 sep 00
Hello Gene!
My translator tool has a special idea about your name, but god knows what it
would think about mine.
You did not say to what cone you fired, the limit table of my software, (and
a bit my experience), shoes it would be for about 1280 -1300C. Is it so? If
not I would suggest you to decrease the alumina. An easy way, will be to put
half of the kaolin. There is another idea that I have about similar glazes
to this one, when I shall write about (put it together in my head) I will
forward you the letter.
And remember the greatness of the internet, I can be year best friend even
(or because) there are some thousand mills between us.
Saphir blue
===========
epk................. 26.00 22.41%
frit3134............ 43.00 37.07%
custer feldspar..... 26.00 22.41%
silica.............. 15.00 12.93%
rutile.............. 4.00 3.45%
cobalt oxide........ 2.00 1.72%
========
116.00
CaO 0.58* 7.94%
MgO 0.00* 0.02%
K2O 0.11* 2.50%
Na2O 0.31* 4.72%
TiO2 0.18 3.58%
ZrO2 0.00 0.03%
Al2O3 0.52 12.99%
B2O3 0.53 9.00%
P2O5 0.00 0.06%
SiO2 4.00 58.84%
Fe2O3 0.01 0.30%
Si:Al 7.69
SiB:Al 8.70
Expan 7.54
(through Insight)
Ababi Sharon
sharon@shoval.org.il
http://www.milkywayceramics.com/cgallery/asharon.htm
----- Original Message -----
From: Arnolds Home Improvements
To:
Sent: Friday, September 08, 2000 12:53
Subject: saffire blue recipe
> Thanks to all who have responded so far. As I said I am new to pottery and
> to the clay art list, so I will make some mistakes at both until I learn,
> but I will learn! Because I am a 50 year old building contractor that has
> fallen in love with clay.
> I understand now if you have a question about a recipe post it.(duh on my
> part) so here is the one I use.
> epk 26
> frit3134 43
> custer feldspar 26
> silica 15
> rutile 4
> cobalt oxide 2
>
> I ran one test with the glaze thick it came out a cloudy blue, next test I
> thinned the glaze until it would pass the dry finger test, this is when I
> get the green. I tried double dipping some pots with the glaze thinnned. I
> had to grind kiln shelves the next day! (by the way I own a dremmel and an
> angle grinder, the angle grinder works best)
> I screen my glaze twice with a100 mesh screen.
> If I add more cobalt will this be food safe?
> I do not know the iron content of my clay, I use standards #153
> Again I would like to thank all who responded at least I don't feel so all
> alone now.
> If I need to post more information please let me know . I think this will
> be a beautiful glaze if all the bugs get worked out.
>
> Gene Arnold
> mudduck@advi.net
>
>
____________________________________________________________________________
__
> 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.
Arnolds Home Improvements on mon 11 sep 00
Hello Ron
Thanks for responding to my post on saffire blue. Good to finally chat with
you. I read all your posts,some I don't understand being a rookie but given
time I will learn.
Enough babble ,just a couple of questions.
Where does the boron come from? I don't know which ingredient contains the
boron. I am assuming it is the frit, just a guess. If it is the frit do I
need to reduce the amount of frit and increase something else?
I am guessing again that the alumina comes from the EPK?
what does it mean to make the glaze more refractory?
This may not be the glaze I"m looking for. what I'm looking for is a stable
non GB glaze that will break brown, dark blue and light speckles. Do you
have any suggestions of a cone 6 oxidation glaze that will give me this
effect?
Again many thanks, it doesn't feel so lonely out here in rookie land when so
many good people are willing to come to the rescue.
Gene Arnold
mudduck@advi.net
Ron Roy on mon 11 sep 00
Hi Gene,
I don't see a problem with food safety but that is a guess. Testing will
tell you the full story. The only oxides that can be questionable are the
cobalt and the boron - there is a lot of boron in this glaze. The question
is - are there phase separations - glaze separating into two separate
glazes - a distinct possibility with all that boron as I understand it.
I am assuming you are firing to cone 6 - oh yes - I see your additional post.
There is enough alumina in this glaze but you may want to increase the EPK
2% at a time in a series of tests - that is the way to stop the running but
the colour may be not what you want - in that case get back to me and I
will make other suggestions.
You may also want to use Titanium dioxide (TiO2) instead of rutile - same
stuff but the rutile has some iron contamination.
Some say this type of glaze works better at cone 5 but I think it would
then be a matter of making the glaze a bit more refractory.
RR
>Thanks to all who have responded so far. As I said I am new to pottery and
>to the clay art list, so I will make some mistakes at both until I learn,
>but I will learn! Because I am a 50 year old building contractor that has
>fallen in love with clay.
>I understand now if you have a question about a recipe post it.(duh on my
>part) so here is the one I use.
>epk 26
>frit3134 43
>custer feldspar 26
>silica 15
>rutile 4
>cobalt oxide 2
>
>I ran one test with the glaze thick it came out a cloudy blue, next test I
>thinned the glaze until it would pass the dry finger test, this is when I
>get the green. I tried double dipping some pots with the glaze thinnned. I
>had to grind kiln shelves the next day! (by the way I own a dremmel and an
>angle grinder, the angle grinder works best)
>I screen my glaze twice with a100 mesh screen.
>If I add more cobalt will this be food safe?
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Armand Grez on tue 12 sep 00
chrisclarke wrote:
>
> I didn't respond before about the saffire blue because everyone seemed to know what
> specific recipie you were talking about but me. But I just read your new post.
> I've been working in cone6 oxidation forever. I have a matt blue that breaks
> green, I also have a very very very, dark blue that breaks lighter brown (a little
> redish) and has a tan dust. I'd be happy to share. chris@ccpots
Please share these recipes with us...glazes are like tonic; they pick me
up when I'm down and right now I can't get much lower!
Andrea
Ron Roy on tue 12 sep 00
Hi Gene,
Just add more clay (EPK) because you said it was running when thick. I am
hoping it will help cure the colour problem as well.
Alumina comes from clay and the feldpars - I'm just trying to keep it
simple for you. Let me know what happened with the clay additions and we
will go from there.
Leave everything else the same.
Yes the boron comes from the frit or GB or one of the so called substitutes
- I need the recipe in front of me to talk about it properly and I don't
have it.
RR
>Thanks for responding to my post on saffire blue. Good to finally chat with
>you. I read all your posts,some I don't understand being a rookie but given
>time I will learn.
>
>Enough babble ,just a couple of questions.
>Where does the boron come from? I don't know which ingredient contains the
>boron. I am assuming it is the frit, just a guess. If it is the frit do I
>need to reduce the amount of frit and increase something else?
>
>I am guessing again that the alumina comes from the EPK?
>
>what does it mean to make the glaze more refractory?
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
chrisclarke on tue 12 sep 00
I didn't respond before about the saffire blue because everyone seemed to know what
specific recipie you were talking about but me. But I just read your new post.
I've been working in cone6 oxidation forever. I have a matt blue that breaks
green, I also have a very very very, dark blue that breaks lighter brown (a little
redish) and has a tan dust. I'd be happy to share. chris@ccpots
Arnolds Home Improvements wrote:
> Hello Ron
>
> Thanks for responding to my post on saffire blue. Good to finally chat with
> you. I read all your posts,some I don't understand being a rookie but given
> time I will learn.
>
> Enough babble ,just a couple of questions.
> Where does the boron come from? I don't know which ingredient contains the
> boron. I am assuming it is the frit, just a guess. If it is the frit do I
> need to reduce the amount of frit and increase something else?
>
> I am guessing again that the alumina comes from the EPK?
>
> what does it mean to make the glaze more refractory?
>
> This may not be the glaze I"m looking for. what I'm looking for is a stable
> non GB glaze that will break brown, dark blue and light speckles. Do you
> have any suggestions of a cone 6 oxidation glaze that will give me this
> effect?
>
> Again many thanks, it doesn't feel so lonely out here in rookie land when so
> many good people are willing to come to the rescue.
>
> Gene Arnold
> mudduck@advi.net
>
> ______________________________________________________________________________
> 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.
Dias3@AOL.COM on wed 13 sep 00
I am just starting to try cone 6 clay and glazes .My previous experience was
with full time production at cone 9 reduction and I'm ready to go back to
clay
as a hobby and have some fun.I have been away from clay for about 10 years
and would really appreciate seeing the glaze recipies that you have. Thanks
for your help.
Brian Wilson
dias3@aol.com
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