VeenaRaghavan@CS.COM on sun 21 aug 05
A question for the glaze experts. I would appreciate any help, if you have
the time to respond.
The following glaze was posted by Alisa Clausen (Thanks, Alisa, not only for
this, but for all your tests.)
It comes out a very nice glossy black on brown stoneware, white stoneware,
and porcelain.
I am wondering if it is safe to use on functional ware. I do not have a glaze
calculation program, so would appreciate any help. We are testing glazes for
the clay studio, where I do some of my work, and I do not want to add a glaze
that is not safe for functional ware to their glazes for everyone to use, as
there will be no control on what the glazes are used for, such as mugs,
bowls,etc.
Here is the recipe:
Barnard Slip/Blackbird 50
Frit 3124 50
Thank you in advance.
Veena
VeenaRaghavan@cs.com
John Hesselberth on sun 21 aug 05
On Aug 21, 2005, at 12:31 PM, VeenaRaghavan@CS.COM wrote:
>
> I am wondering if it is safe to use on functional ware. I do not have=20=
> a glaze
> calculation program, so would appreciate any help. We are testing=20
> glazes for
> the clay studio, where I do some of my work, and I do not want to add=20=
> a glaze
> that is not safe for functional ware to their glazes for everyone to=20=
> use, as
> there will be no control on what the glazes are used for, such as =
mugs,
> bowls,etc.
>
> Here is the recipe:
>
> Barnard Slip/Blackbird 50
> Frit 3124 50
Hi Veena,
This glaze should be pretty durable and there is nothing in it to worry=20=
about it. I would vinegar test it just to be sure it will hold up well=20=
in use, but I suspect it would pass. It has plenty of silica and=20
alumina--maybe a little on the high side for cone 6--but it also has an=20=
extra dollop of boron to help it melt. The balance of fluxes is fine. I=20=
have pasted the unity numbers below. The only problem I see is that it=20=
will probably craze on most clays. Crazing is hard to see on black=20
glossy glazes. Hold it up to the steam coming out of your tea kettle=20
and then look for crazing. It would take a bit of fiddling to keep it=20
from crazing with all that sodium in it, but it could probably be done=20=
by adding talc and/or silica.
John
Amount Ingredient
50 Clay--Barnard Slip
50 Frit--Ferro 3124
0
100 Total
Unity Oxide
.271 Na2O
.048 K2O
.041 MgO
.64 CaO
1.000 Total
.42 Al2O3
.481 B2O3
.519 Fe2O3
4.167 SiO2
.007 TiO2
9.9 Ratio
77.4 Exp
Comments:
-----------------------------------
Calculations by GlazeMaster=99
www.masteringglazes.com
------------------------------------
>
John Hesselberth
http://www.frogpondpottery.com
http://www.masteringglazes.com
Ron Roy on mon 22 aug 05
Hi Veena,
I would say yes - lots of silica and alumina and certainly well melted -
and nothing particularly toxic anyway.
Barnard does have a fair amount of Manganese so it could be a problem for
the potter - from dust and firing.
Where will you get the Barnard?
Best regards - RR
>A question for the glaze experts. I would appreciate any help, if you have
>the time to respond.
>
>The following glaze was posted by Alisa Clausen (Thanks, Alisa, not only for
>this, but for all your tests.)
>
>It comes out a very nice glossy black on brown stoneware, white stoneware,
>and porcelain.
>
>I am wondering if it is safe to use on functional ware. I do not have a glaze
>calculation program, so would appreciate any help. We are testing glazes for
>the clay studio, where I do some of my work, and I do not want to add a glaze
>that is not safe for functional ware to their glazes for everyone to use, as
>there will be no control on what the glazes are used for, such as mugs,
>bowls,etc.
>
>Here is the recipe:
>
>Barnard Slip/Blackbird 50
>Frit 3124 50
>
>Thank you in advance.
>
>Veena
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Kathy Stecker on tue 23 aug 05
Hi folks,
When discussing this glaze Ron Roy asked, Where will you get the Barnard?
Is he inferring that Barnard Slip is unavailable the way Albany is?
Perhaps it would be a good time to review what minerals are endangered or
extinct in terms of availability?Anyone want to enlighten us?Thanks!
Kathy Stecker
Winter Springs FL
Edouard Bastarache Inc. on wed 24 aug 05
Hello Kathy,
here is an analysis for Barnard Slip (Black Bird)
From this point you could work out a substitution
if it is unavailable ;
SiO2 59.7
Al2O3 10.8
Fe2O3 14.65
TiO2 .67
CaO .27
MgO .75
MnO 3.4
K2O 2.04
Na2O .12
L.O.I. 7.46
Later,
"Ils sont fous ces quebecois"
"They are insane these quebekers"
"Están locos estos quebequeses"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
www.sorel-tracy.qc.ca/~edouardb/Welcome.html
http://retrodemonstration.blogspot.com/
http://www.flickr.com/photos/potier/
http://perso.wanadoo.fr/smart2000/index.htm
http://www.digitalfire.com/education/toxicity/
----- Original Message -----
From: "Kathy Stecker"
To:
Sent: Tuesday, August 23, 2005 10:47 PM
Subject: Re: Ebony cone 6 glaze
> Hi folks,
>
> When discussing this glaze Ron Roy asked, Where will you get the Barnard?
>
> Is he inferring that Barnard Slip is unavailable the way Albany is?
>
> Perhaps it would be a good time to review what minerals are endangered or
> extinct in terms of availability?Anyone want to enlighten us?Thanks!
>
> Kathy Stecker
>
> Winter Springs FL
>
> ______________________________________________________________________________
> 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.
>
>
pinacoid3000@LYCOS.COM on wed 24 aug 05
Hi Kathy,
You asked =93 ... are endangered or extinct in terms of availability=94 Well=
Cornwall / Cornish / China stone has being hanging on by an ever thinning
thread for some years. How many years it will remain in production is
unknown but it may may well not be here for the long term
Regards,
Andy
Ron Roy on fri 26 aug 05
This is the analysis I have for Barnard - I would expect many different
analysis for this kind of material.
SiO2 52.61
Al2O3 10.62
Fe2O3 20.27 < big difference
TiO2 .90
CaO none
MgO none
MnO 3.30
>K2O 3.80
>Na2O none
>L.O.I. 8.50
RR
>Hello Kathy,
>
>here is an analysis for Barnard Slip (Black Bird)
>From this point you could work out a substitution
>if it is unavailable ;
>
>SiO2 59.7
>Al2O3 10.8
>Fe2O3 14.65
>TiO2 .67
>CaO .27
>MgO .75
>MnO 3.4
>K2O 2.04
>Na2O .12
>L.O.I. 7.46
>Edouard Bastarache
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Edouard Bastarache Inc. on fri 26 aug 05
From Bob Wilt's GlazeChem ;
A high-iron clay from glacial deposits.
Manufactured by Hammill & Gillespie; comes from western
Pennsylvania.
Non-plastic, dark brown; starts to melt at c/4.
Analyses:
Obstler:
% 0.12 Na2O 2.04 K2O 0.75 MgO 0.27 CaO 10.87 Al2O3
59.7 SiO2 0.67 TiO2 14.65 Fe2O3 3.4 MnO 7.48 LOI
(also present: Ba, Pb, Zr, Sr, Ni)
Cooper & Royle: (Appendix 8)
% 3.77 K2O 10.60 Al2O3 52.38 SiO2 0.85 TiO2
20.27 Fe2O3 3.23 MnO 8.27 LOI
Chappell:
% 0.5 Na2O 1.0 K2O 0.6 MgO 0.5 CaO 6.7 Al2O3
41.4 SiO2 0.2 TiO2 29.9 Fe2O3 3.25 MnO 8.4 LOI
Cushing:
% 0.12 Na2O 2.04 K2O 0.75 MgO 0.27 CaO 10.8 Al2O3
59.7 SiO2 0.67 TiO2 14.6 Fe2O3 5.4 MnO 7.48 LOI
Tichane (AG):
% 4.0 K2O 10.6 Al2O3 52.4 SiO2 0.9 TiO2
20.3 Fe2O3 3.2 MnO 8.3 LOI
Tichane (TCB, CB):
% 3.8 K2O 10.6 Al2O3 52.4 SiO2 0.9 TiO2
20.3 Fe2O3 3.2 MnO 8.3 LOI
IMC:
% 0.57 Na2O 1.14 K2O 0.68 MgO 0.57 CaO 7.60 Al2O3
47.01 SiO2 0.23 TiO2 33.90 Fe2O3 8.31 LOI
IMC: (Blackbird)
% 0.12 Na2O 2.04 K2O 0.75 MgO 0.27 CaO 10.87 Al2O3
59.70 SiO2 0.67 TiO2 14.65 Fe2O3 3.40 MnO 7.46 LOI
Later,
"Ils sont fous ces quebecois"
"They are insane these quebekers"
"Están locos estos quebequeses"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
www.sorel-tracy.qc.ca/~edouardb/Welcome.html
http://retrodemonstration.blogspot.com/
http://www.flickr.com/photos/potier/
http://perso.wanadoo.fr/smart2000/index.htm
http://www.digitalfire.com/education/toxicity/
----- Original Message -----
From: "Ron Roy"
To:
Sent: Friday, August 26, 2005 1:19 AM
Subject: Re: Ebony cone 6 glaze
> This is the analysis I have for Barnard - I would expect many different
> analysis for this kind of material.
>
> SiO2 52.61
> Al2O3 10.62
> Fe2O3 20.27 < big difference
> TiO2 .90
> CaO none
> MgO none
> MnO 3.30
>>K2O 3.80
>>Na2O none
>>L.O.I. 8.50
>
> RR
>
>>Hello Kathy,
>>
>>here is an analysis for Barnard Slip (Black Bird)
>>From this point you could work out a substitution
>>if it is unavailable ;
>>
>>SiO2 59.7
>>Al2O3 10.8
>>Fe2O3 14.65
>>TiO2 .67
>>CaO .27
>>MgO .75
>>MnO 3.4
>>K2O 2.04
>>Na2O .12
>>L.O.I. 7.46
>
>>Edouard Bastarache
>
> Ron Roy
> RR#4
> 15084 Little Lake Road
> Brighton, Ontario
> Canada
> K0K 1H0
> Phone: 613-475-9544
> Fax: 613-475-3513
>
> ______________________________________________________________________________
> 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.
>
>
| |
|
