Randy McCall on fri 2 nov 07
I am trying to develop an alkaline satin transparent grey green glaze on
buff stoneware cone 6 clay.
I would appreciate it if someone would look at this glaze and see if it
comes close. I will be firing it tomorrow, but would like to know if I can
make changes that will get me closer to the end result. Or whether I am off
track.
Recipe Name: McCall's Celadon Green
Cone: 6 Color: Clear
Firing: Oxidation Surface: Satin
Amount Ingredient
45 Frit--Ferro 3195
30 Ball Clay Number 1
20 Silica
5 Magnesium Carbonate
100 Total
Additives
.5 Nickel Oxide
2 Copper Carbonate
Comments:
-----------------------------------
Calculations by GlazeMasterT
www.masteringglazes.com
------------------------------------
Randy
South Carolina
Pottery Web site
http://members.tripod.com/~McCallJ/index.html
John Hesselberth on fri 2 nov 07
Hi Randy,
I don't think you are even close to an alkaline glaze composition.
You might get a grey green, but an alkaline glaze would probably give
you a greyed turquoise with these colorants. An alkaline glaze would
have far more alkalis and far less alkaline earths. This glaze also
has an extremely low COE so watch out for dunting or shivering. This
glaze has all the makings of a 'pot breaker' on anything other than
small thick-walled pieces.
Regards,
John
Hi Randy,On Nov 2, 2007, at 4:19 PM, Randy McCall wrote:
> I am trying to develop an alkaline satin transparent grey green
> glaze on
> buff stoneware cone 6 clay.
>
> I would appreciate it if someone would look at this glaze and see
> if it
> comes close. I will be firing it tomorrow, but would like to know
> if I can
> make changes that will get me closer to the end result. Or whether
> I am off
> track.
>
>
> Recipe Name: McCall's Celadon Green
>
> Cone: 6 Color: Clear
> Firing: Oxidation Surface: Satin
>
> Amount Ingredient
> 45 Frit--Ferro 3195
> 30 Ball Clay Number 1
> 20 Silica
> 5 Magnesium Carbonate
>
> 100 Total
>
> Additives
> .5 Nickel Oxide
> 2 Copper Carbonate
>
>
> Comments:
> -----------------------------------
> Calculations by GlazeMasterT
> www.masteringglazes.com
> ------------------------------------
>
>
> Randy
> South Carolina
> Pottery Web site
>
> http://members.tripod.com/~McCallJ/index.html
>
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John Hesselberth
www.frogpondpottery.com
"Man is a tool-using animal....without tools he is nothing, with
tools he is all" .... Thomas Carlyle
Ron Roy on sun 4 nov 07
Hi Randy,
As John said - not an alkaline glaze - which needs to be dominated by
sodium, potassium and/or lithium. They usually have so much sodium and
potassium in them you can't stop the crazing.
The expansion is way low - I'll be surprised if you don't have shivering on
your test. Have a good look with a magnifying glass at any sharp edges -
especially around the rim on the outside.
I'm curious why you used Magnesium Carb when you could have used Talc?
RR
>I am trying to develop an alkaline satin transparent grey green glaze on
>buff stoneware cone 6 clay.
>
>I would appreciate it if someone would look at this glaze and see if it
>comes close. I will be firing it tomorrow, but would like to know if I can
>make changes that will get me closer to the end result. Or whether I am off
>track.
>
>
>Recipe Name: McCall's Celadon Green
>
>Cone: 6 Color: Clear
>Firing: Oxidation Surface: Satin
>
>Amount Ingredient
>45 Frit--Ferro 3195
>30 Ball Clay Number 1
>20 Silica
>5 Magnesium Carbonate
>
>100 Total
>
> Additives
> .5 Nickel Oxide
> 2 Copper Carbonate
>
>
>Comments:
>Randy
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Randy McCall on sun 4 nov 07
R and J
Tested the glaze and it came out a nice smooth glaze on vertical test
pieces, but it was a very muddy transparent brown green color. Not at all
the color I was looking for in the glaze. Has a nice smooth texture.
I think I may try another route and use a boro glaze with some iron and
copper see to see if I can get the greyed transparent green with some depth.
Looking for a brighter green than the mud I got with the below glaze. I
usually fast fire up and down, but have recently discovered that by holding
on medium for an hour at 1650 deg F gives you some satiny glazes that have a
lot of depth I have not been able to get before.
I was using the magnesium carb as I had read that it would give the glaze a
buttery texture which it did.
Technically I really don't know much about glazes, just try them till I find
something I like.
Waiting on a glaze workshop that is close by sometime in the future. Have
both Cone 6 glaze books and software.
Thanks for the comments.
Hi Randy,
As John said - not an alkaline glaze - which needs to be dominated by
sodium, potassium and/or lithium. They usually have so much sodium and
potassium in them you can't stop the crazing.
The expansion is way low - I'll be surprised if you don't have shivering on
your test. Have a good look with a magnifying glass at any sharp edges -
especially around the rim on the outside.
I'm curious why you used Magnesium Carb when you could have used Talc?
RR
>I am trying to develop an alkaline satin transparent grey green glaze on
>buff stoneware cone 6 clay.
>
>I would appreciate it if someone would look at this glaze and see if it
>comes close. I will be firing it tomorrow, but would like to know if I can
>make changes that will get me closer to the end result. Or whether I am
>off
>track.
>
>
>Recipe Name: McCall's Celadon Green
>
>Cone: 6 Color: Clear
>Firing: Oxidation Surface: Satin
>
>Amount Ingredient
>45 Frit--Ferro 3195
>30 Ball Clay Number 1
>20 Silica
>5 Magnesium Carbonate
>
>100 Total
>
> Additives
> .5 Nickel Oxide
> 2 Copper Carbonate
>
>
>Comments:
>Randy
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Randy
South Carolina
Pottery Web site
http://members.tripod.com/~McCallJ/index.html
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