Margaret Carroll on mon 1 sep 08
Have a great combination of Purple Opal on a warm brown grogged clay =
with a lip dip of blue. ^6 ox. However, the
great effect only happens at ^6 at which point the Purple Opal runs =
right off the pot. If I take it to ^5, it doesn't run but I lose the =
great effect. Is there a modification of the recipe that would stop =
this happening - such as Bentonite or more EPK?
Gerstley Borate 140
Spodumeme 300
EPK 50
Dolomite 70
Talc 130
Flint 200
Rutile 60
Manganese Dioxide 10
Any suggestions welcomed. Margaret Carroll
Steve Slatin on mon 1 sep 08
Margaret --
A quick look at this glaze shows you've got
lots of powerful melters -- 5.69% lithium,
9.78 Magnesium, 3.81% Boron, with only 6.57%
alumina. (Total fluxes, including boron,
come to 28.52.) At ^6, that's too much
melting for that amount of alumina.
Tipping up slightly in alumina should fix
things for you with regard to running --
but you should be aware that with lots of
boron and titanium in your glaze, it may
'work' for the opal effect because of a
phase separation in the glass, and it's
at least possible that extra alumina will
interfere with this.
If you added 90 EPK (or a similar kaolin)
you'd have something that comes out to
a round number, and it'd be slightly higher
in silica, much higher in alumina, and the
balance would largely come out of the fluxes,
which is what I'd do as a test.
Cooler heads would probably do a line blend,
and learn more ... but the idea would remain
the same, mix up a small standard batch of
this, and a batch with a good jolt of clay
in it, and figure out where in blends of the
two you'd get all your color without being
too runny.
Good luck -- and please tell us what results
you have, whatever you try.
-- Steve Slatin
--- On Mon, 9/1/08, Margaret Carroll wrote:
> Have a great combination of Purple Opal on a warm brown
> grogged clay with a lip dip of blue. ^6 ox. However, the
> great effect only happens at ^6 at which point the Purple
> Opal runs right off the pot. If I take it to ^5, it
> doesn't run but I lose the great effect. Is there a
> modification of the recipe that would stop this happening -
> such as Bentonite or more EPK?
> Gerstley Borate 140
> Spodumeme 300
> EPK 50
> Dolomite 70
> Talc 130
> Flint 200
> Rutile 60
> Manganese Dioxide 10
>
> Any suggestions welcomed. Margaret Carroll
Mayssan Farra on mon 1 sep 08
Hello Margaret:=0A=0AI also love this glaze, although I do it without the M=
anganese Dioxide for safty's sake and=A0it works great, but on vertical sur=
faces=A0I only lip=A0dip it after I dip the whole pot in whatever glaze I w=
ant. It=A0does also wonderful things on the horizental surfaces if you appl=
y it with a brush tap tap tap like you do stenciling. =A0=0A=0A=0A=A0=0AMay=
ssan Shora Farra=0Ahttp://www.clayvillepottery.com=0Ahttp://clayette.blogsp=
ot.com=0A=0AHave a great combination of Purple Opal on a warm brown grogged=
clay with a lip dip of blue.=A0 ^6 ox.=A0 However, the=0Agreat effect only=
happens at ^6 at which point the Purple Opal runs right off the pot.=A0 If=
I take it to ^5, it doesn't run but I lose the great effect.=A0 Is there a=
modification of the recipe that would stop this happening - such as Benton=
ite or more EPK?=0AGerstley Borate 140=0ASpodumeme=A0 =A0 =A0 300=0AEPK=A0 =
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 50=0ADolomite=A0 =A0 =A0 =A0 =A0 =A0 70=0AT=
alc=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 130=0AFlint=A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 200=0ARutile=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 60=0AMa=
nganese Dioxide 10=0A=0AAny suggestions welcomed.=A0 Margaret Carroll=0A=0A=
=0A=0A
Alisa Clausen on wed 3 sep 08
Hi Margaret
I have followed the thread on this glaze with interest. It is a glaze I
have tested many times and have never seen any opalescence by itself.
However, over other glazes, it can be quite blue.
I have in the past used a different recipe for the same effect, one I saw on
Clayart a long time ago. Just to have more to test...! here it is:
Cream of Mushroom ^6 ox
10.66 Spodumene
40.67 Neph. Sye.
9.62 Whiting
23.34 Flint
7.55 Gerstely Borate
4.81 Dolomite
3.35 Zinc Oxide
ADD
4 Rutile
1 RIO
1.52 Bentonite
10.15 Zircopax
I round up all the amounts and do not add the Bentonite
I also use a Boron Frit (you can try 3134) instead of the G.B.
I have other over glazes, as I call them, similar if you want more.
Also comes to mind, the one published in CM also a long time ago, an article
on Chris Wolff and his glazes:
Cream Gloss
30 G.B can use 3134
10 Whiting
35 Custer Feld.
15 Soda feldspar or Cornwall Stone
10 Flint
2 RIO
3 Rutile
Best regards, Alisa in Denmark
On Mon, Sep 1, 2008 at 6:28 PM, Margaret Carroll wrote:
> Have a great combination of Purple Opal on a warm brown grogged clay with a
> lip dip of blue. ^6 ox. However, the
> great effect only happens at ^6 at which point the Purple Opal runs right
> off the pot. If I take it to ^5, it doesn't run but I lose the great
> effect. Is there a modification of the recipe that would stop this
> happening - such as Bentonite or more EPK?
> Gerstley Borate 140
> Spodumeme 300
> EPK 50
> Dolomite 70
> Talc 130
> Flint 200
> Rutile 60
> Manganese Dioxide 10
>
> Any suggestions welcomed. Margaret Carroll
>
Ron Roy on thu 4 sep 08
Hi Margaret,
Try increasing the EPK to 60, then to 70 - then to 80 - three different
tests - just make up 1000 grams each to see if that will stop the running
at cone 6.
I would not recommend this glaze as a liner by the way - it's short of
silica - if you do want to use it that way you should have it tested to see
if it's stable.
Be careful with the Manganese - the dust is toxic and the firing fumes are
a danger.
The expansion of this glaze is very low - would you like to try a version
with the expansion adjusted to a safer level? If so tell me what feldspar
you have.
RR
>Have a great combination of Purple Opal on a warm brown grogged clay with
>a lip dip of blue. ^6 ox. However, the
>great effect only happens at ^6 at which point the Purple Opal runs right
>off the pot. If I take it to ^5, it doesn't run but I lose the great
>effect. Is there a modification of the recipe that would stop this
>happening - such as Bentonite or more EPK?
>Gerstley Borate 140
>Spodumeme 300
>EPK 50
>Dolomite 70
>Talc 130
>Flint 200
>Rutile 60
>Manganese Dioxide 10
>
>Any suggestions welcomed. Margaret Carroll
Ron Roy
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Margaret Carroll on thu 4 sep 08
That would be wonderful. Yes, I use Custer Feldspar mainly but have the
other too.... Will try your suggestions on the next batch...and eagerly
await the reformulation.
Thank you. Margaret
----- Original Message -----
From: "Ron Roy"
To:
Sent: Thursday, September 04, 2008 5:33 AM
Subject: Re: Purple Opal glaze running
> Hi Margaret,
>
> Try increasing the EPK to 60, then to 70 - then to 80 - three different
> tests - just make up 1000 grams each to see if that will stop the running
> at cone 6.
>
> I would not recommend this glaze as a liner by the way - it's short of
> silica - if you do want to use it that way you should have it tested to
> see
> if it's stable.
>
> Be careful with the Manganese - the dust is toxic and the firing fumes are
> a danger.
>
> The expansion of this glaze is very low - would you like to try a version
> with the expansion adjusted to a safer level? If so tell me what feldspar
> you have.
>
> RR
>
>
>>Have a great combination of Purple Opal on a warm brown grogged clay with
>>a lip dip of blue. ^6 ox. However, the
>>great effect only happens at ^6 at which point the Purple Opal runs right
>>off the pot. If I take it to ^5, it doesn't run but I lose the great
>>effect. Is there a modification of the recipe that would stop this
>>happening - such as Bentonite or more EPK?
>>Gerstley Borate 140
>>Spodumeme 300
>>EPK 50
>>Dolomite 70
>>Talc 130
>>Flint 200
>>Rutile 60
>>Manganese Dioxide 10
>>
>>Any suggestions welcomed. Margaret Carroll
>
> Ron Roy
> 15084 Little Lake Road
> Brighton, Ontario
> Canada
> K0K 1H0
>
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7:15 AM
Ron Roy on sun 7 sep 08
This looks like it is a stable glaze by the way - a little better with the
frit version. Remember - rutile has an important role in stable glazes - it
helps a lot to prevent leaching.
The second glaze with F4 spar will probably not be stable - maybe with the
cornwall stone - with frit 3134 it will be much better. Expansion is high
so you can expect crazing on most bodies.
RR
>Cream of Mushroom ^6 ox
>10.66 Spodumene
>40.67 Neph. Sye.
>9.62 Whiting
>23.34 Flint
>7.55 Gerstely Borate
>4.81 Dolomite
>3.35 Zinc Oxide
>
>ADD
>4 Rutile
>1 RIO
>1.52 Bentonite
>10.15 Zircopax
>
>I round up all the amounts and do not add the Bentonite
>I also use a Boron Frit (you can try 3134) instead of the G.B.
>Cream Gloss
>30 G.B can use 3134
>10 Whiting
>35 Custer Feld.
>15 Soda feldspar or Cornwall Stone
>10 Flint
>
>2 RIO
>3 Rutile
>
>Best regards, Alisa in Denmark
Ron Roy
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
sacredclay on sun 7 sep 08
> frit version. Remember - rutile has an important role in stable
glazes - it
> helps a lot to prevent leaching.
>
>
> RR
>
>
If CuCo3 was used as a wash on a plate and a glaze that contained
rutile was put over it, would it contain the leaching? Kathryn Hughes
in NC
Margaret Carroll on sun 7 sep 08
Alicia Clausen ...Your "Cream of Mushroom ^6ox recipe seems destined, =
from the name and the ingredients, to result in a dark cream color =
rather than a purple opal. In the archives I note that on Feb. 16, 05, =
you posted a glaze test for Purple Opal with the same ingredients as =
mine...but then offered two alternatives: adding 2 cobalt carb for a =
dark blue purple mat glaze ( or 4-6 copper carb for a semi mat glass =
green glaze). Also, I use Chris Wolff's cream glaze in combination =
with other glazes for an interesting effect but always thought it kept =
its cream color integrity. Am I wrong on both counts and your Mushroom =
and the Wolff cream glaze result in opalescence? My, I have a lot to =
learn. Thank you. Margaret
Margaret Carroll on sun 7 sep 08
Alisa... my apologies. I misspelled your name. Margaret
Alisa Clausen on mon 8 sep 08
Hi Margaret
The Cream of Mushroom has shown opalescence by itself on darker bodies as
well as my usual white stoneware. The Cream also shows opalescence, a lot,
over an iron rich glaze. By itself it can be very yellowish with only
tinges of blue, if any. I use them both as overglazes for opalescence and
fluid overlapping effects.
Thanks for writing,
Alisa in Denmark
PS Not a lot of people spell or say my name as I am called. Ah lee sa! I
have a twin named Max, just Max, no amillion or well. So, I call him Ah
Max.
On Mon, Sep 8, 2008 at 12:53 AM, Margaret Carroll wrote:
> Alicia Clausen ...Your "Cream of Mushroom ^6ox recipe seems destined, from
> the name and the ingredients, to result in a dark cream color rather than a
> purple opal. In the archives I note that on Feb. 16, 05, you posted a glaze
> test for Purple Opal with the same ingredients as mine...but then offered
> two alternatives: adding 2 cobalt carb for a dark blue purple mat glaze (
> or 4-6 copper carb for a semi mat glass green glaze). Also, I use Chris
> Wolff's cream glaze in combination with other glazes for an interesting
> effect but always thought it kept its cream color integrity. Am I wrong on
> both counts and your Mushroom and the Wolff cream glaze result in
> opalescence? My, I have a lot to learn. Thank you. Margaret
>
Ron Roy on mon 15 sep 08
Hi Kathryn,
I don't know the answer - you will have to have it tested to find out. The
indication is that a stable glaze over an unstable glaze will prevent
leaching.
I tend to think it would depend of the stability of the over glaze and how
thick the wash is. Probably still better than putting the copper right in
the glaze.
Wish I had a more definite answer - somebody should be doing some
experiments on this sort of thing.
RR
>> frit version. Remember - rutile has an important role in stable
>glazes - it
>> helps a lot to prevent leaching.
>>
>
>>
>> RR
>>
>>
> If CuCo3 was used as a wash on a plate and a glaze that contained
>rutile was put over it, would it contain the leaching? Kathryn Hughes
>in NC
Ron Roy
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
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