Khaimraj Seepersad on tue 4 jul 00
Greetings to All ,
Happy 4th of July .
Yesterday , I decided to end my curiosity about Richard Behrens'
Wide - Range - Firing Glazes - Glaze 1 [ cone 018 to 010 ]
A Clear Glaze .
Lithium Carbonate - 10.0
Frit 269 [ sub 3269 Ferro ] - 44.2
Frit 3134 [ Ron Roy's Fav. ] - 25.1
Kaolin - 7.1
Flint [ I used crushed quartz , -325 mesh ] - 13.6
and 3.5 Bentonite to suspend .
TOXIC - Lithium Carbonate - Boric Oxide and Fluorine .
This one occurs in his two books about 3 times , and I just never
tried it .
I estimate that it looks like this -
4.2 Li20
3.8 K20
7.9 Na20
5.4 Ca0
0.2 Zn0
9.1 Al203
13.3 B203
53.5 Si02 - guesstimated Fluorine content less than 2.5 %
I can not give an expansion for pottery , as I use enamel
expansion factors where Na20 = 12 , K20 = 8.5 and
Mg0 = 0.1
We know that using Lithium oxide often gives 3x times the
amount of Sodium Oxide - so 4.3 Li20 = 12.9 Na20 .
Without increasing the alkali , the glaze is still subjected to
24.3 % alkali .
So setting the Test Kiln to slowest firing for glazes , [ leave
the top open about 11/4 inches / 3.5 cms ] .
Gloss occurred as low as 630 deg.c / 1115 deg.f , which I
discounted due to extra radiant heat , for such a small space,
internal of the test kiln being 4 x 6 x 6 inches / 10 x 15 x 15
cms or 4 old kiln blocks and two larger blocks for bottom and
top .
To test the pyro , I left a standing triangle of Aluminium Metal ,
aluminium melts at 660.2 deg.c / approx. . 1223 deg.f .
This occurred when the pyro read 650 deg.c .
By 750 deg.c pyro , the glaze samples , were clear , but the
porous bodies had bubbles .
The bodies used were a porous , flower pot [ clay and sand ] ,
and a vitreous earthenware .
I ran the tests to 919 deg.c / 1686 deg.f , glazes were clear ,
bubble free on vitreous bodies but finely bubbled on porous
bodies . Signs of glaze flow were noted [ areas applied thickly
to deliberately look for this ] .
Firing time to completion - 6 hrs .
I would not use this as a Food or Drink Glaze , and as soon as
I get some bowls built , a sending to Alfred's is in order .
I would like to see just how chemically durable this glaze is .
Cones were not used because the firings were so low and the
pyro is usually accurate at this level , as I do a good deal of
Porcelain enamels for application on pottery , under 900 deg.c
is usually second nature .
Use - hmm , would be interesting as a majolica - say at the
Assyrian or Babylonian level - under 900 deg.c .
Perhaps , glazed burnished ware [ burnishing losing it's shine
at 850 deg.c - using well clean earthenware slip ] .
Fritting the entire glaze , made from oxides , and using it as an
enamel on a clear glaze .
A durable interior glaze for Egyptian Paste , when the internal
glazing forms poorly or not at all .
Khaimraj
* Cost is not a factor if you frit the glaze for yourself .
Liz Gowen on tue 4 jul 00
Khaimraj, might this glaze be usable on unglazed porcelain bisqued
high the glazed low the way industry does for china tableware?
Liz Gowen
-----Original Message-----
From: Khaimraj Seepersad
To: CLAYART@LSV.CERAMICS.ORG
Date: Tuesday, July 04, 2000 1:18 PM
Subject: Glazes at 018 - 752 deg.c / 1386 deg F - Orton small cone
>Greetings to All ,
>Happy 4th of July .
>
>Yesterday , I decided to end my curiosity about Richard Behrens'
>Wide - Range - Firing Glazes - Glaze 1 [ cone 018 to 010 ]
>A Clear Glaze .
>
>Lithium Carbonate - 10.0
>Frit 269 [ sub 3269 Ferro ] - 44.2
>Frit 3134 [ Ron Roy's Fav. ] - 25.1
>Kaolin - 7.1
>Flint [ I used crushed quartz , -325 mesh ] - 13.6
>
>and 3.5 Bentonite to suspend .
>
>TOXIC - Lithium Carbonate - Boric Oxide and Fluorine .
>
>This one occurs in his two books about 3 times , and I just never
>tried it .
>
>I estimate that it looks like this -
>
>4.2 Li20
>3.8 K20
>7.9 Na20
>5.4 Ca0
>0.2 Zn0
>9.1 Al203
>13.3 B203
>53.5 Si02 - guesstimated Fluorine content less than 2.5 %
>
>I can not give an expansion for pottery , as I use enamel
>expansion factors where Na20 = 12 , K20 = 8.5 and
>Mg0 = 0.1
>
>We know that using Lithium oxide often gives 3x times the
>amount of Sodium Oxide - so 4.3 Li20 = 12.9 Na20 .
>Without increasing the alkali , the glaze is still subjected to
>24.3 % alkali .
>
>So setting the Test Kiln to slowest firing for glazes , [ leave
>the top open about 11/4 inches / 3.5 cms ] .
>Gloss occurred as low as 630 deg.c / 1115 deg.f , which I
>discounted due to extra radiant heat , for such a small space,
>internal of the test kiln being 4 x 6 x 6 inches / 10 x 15 x 15
>cms or 4 old kiln blocks and two larger blocks for bottom and
>top .
>
>To test the pyro , I left a standing triangle of Aluminium Metal ,
>aluminium melts at 660.2 deg.c / approx. . 1223 deg.f .
>This occurred when the pyro read 650 deg.c .
>By 750 deg.c pyro , the glaze samples , were clear , but the
>porous bodies had bubbles .
>
>The bodies used were a porous , flower pot [ clay and sand ] ,
>and a vitreous earthenware .
>
>I ran the tests to 919 deg.c / 1686 deg.f , glazes were clear ,
>bubble free on vitreous bodies but finely bubbled on porous
>bodies . Signs of glaze flow were noted [ areas applied thickly
>to deliberately look for this ] .
>Firing time to completion - 6 hrs .
>
>I would not use this as a Food or Drink Glaze , and as soon as
>I get some bowls built , a sending to Alfred's is in order .
>I would like to see just how chemically durable this glaze is .
>
>Cones were not used because the firings were so low and the
>pyro is usually accurate at this level , as I do a good deal of
>Porcelain enamels for application on pottery , under 900 deg.c
>is usually second nature .
>
>Use - hmm , would be interesting as a majolica - say at the
>Assyrian or Babylonian level - under 900 deg.c .
>Perhaps , glazed burnished ware [ burnishing losing it's shine
>at 850 deg.c - using well clean earthenware slip ] .
>Fritting the entire glaze , made from oxides , and using it as an
>enamel on a clear glaze .
>A durable interior glaze for Egyptian Paste , when the internal
>glazing forms poorly or not at all .
>Khaimraj
>
>* Cost is not a factor if you frit the glaze for yourself .
>
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>
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melpots@pclink.com.
>
Khaimraj Seepersad on tue 4 jul 00
Good evening a Tutti ,
Liz ,
ask one of the Glaze Tech. Overlords , if they could run the
glaze through their expansion programmes , and your
porcelain body [ I assume it will be vitreous ? ] as well.
Ron Roy , would probably be able to tell if the glaze / body
fit would work .
He could also tell you if there would be any other problems .
Remember , I wouldn't use this glaze for food or drink
containers , and if you wanted too , please have it tested .
Use a random object test of three containers ----- my paranoia
for Lithium Oxide .
Richard Behrens in his book also suggests a Low Fire
Stoneware type body [ 06 Orton ] , that will fit the glaze .
Sorry , I couldn't give you a more definite answer.
Stay Well ,
Khaimraj
* If I can help in any other way , please ask .
-----Original Message-----
From: Liz Gowen
To: CLAYART@LSV.CERAMICS.ORG
Date: 04 July 2000 14:41
Subject: Re: Glazes at 018 - 752 deg.c / 1386 deg F - Orton small cone
>Khaimraj, might this glaze be usable on unglazed porcelain bisqued
>high the glazed low the way industry does for china tableware?
> Liz Gowen
>
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