Dave Finkelnburg on fri 26 nov 99
Ron,
I almost didn't ask about this glaze, knowing how you feel about it and
a certain one of it's ingredients. :-) I do apologize for frustrating you!
You give so much time and energy to this list regarding glazes. I am sure
others appreciate what you do as much as I do.
I have followed your directions as exactly as I could. The test tiles
are in the kiln now. I'll let you know what they look like tomorrow night.
In your version, I see you:
changed about 1/3 of the Na2O to K2O,
replaced some of the calcium with strontium,
raised the alumina about 25 mole %, and the silica almost 10%, while
reducing the boron by 40%.
Are the alumina/silica changes to increase glaze viscosity? Is the
strontium to get another source of flux or?
I am trying to understand why you made the changes you did. Any insight
into that would be sincerely appreciated.
Dave Finkelnburg in frosty Idaho
----Original Message-----
From: Ron Roy
To: CLAYART@LSV.UKY.EDU
Date: Tuesday, November 23, 1999 10:45 AM
Subject: Re: How to make C5 glaze C6?
----------------------------Original message----------------------------
I'm getting tired of dealing with this glaze - I don't like it - I think
it's dumb and I wish it would go away.
Hi Dave - this is not aimed at you - just some frustratation coming out.
This following recipe is a more balanced glaze - make up 500 grams of it
and 500 of the original and do a 5 part line blend and tell me what happens
- please.
Sieve 2 times through 80m.
After dipping in # 1(your original) and #5 (my revision) take equal amount
of #1 and #5 to make #3 (you will need twice as much of #3 cause you will
need to mix it with #1 to get #2 and again with #5 to get #4 - equal parts.
When you have dipped into #2 and #4 mix it all together to get #3. Fire to
cone 6 (use a large cone beside the tests)
My revision.
Gers Borate - 32.0
Custer - 28.0
Wolastonite - 5.0
Strontium Carb - 3.0
EPK - 11.0
Silica - 21.0
Bentonite - 1.0
Total - 101.0
There that feels better.
It would be even better if you would let me do this with some frit 3134 -
then it would be much better.
RR
>----------------------------Original message----------------------------
>Glaze gurus,
> As some of you recall, I have been struggling with blistering on a
glaze I
>found in Chappell. after numerous tests I've concluded my basic fault has
been
>simply overfiring the glaze. I understand some of the idea of glaze
>calculation
>and limit formulas, such as the differences in alumina, silica between cone
5
>and cone 10 glazes. However, I am really not sure how to calculate a range
for
>testing to adjust this glaze to fire up only one or at most two cones. Can
>someone please explain to me how to predict the change I need to make, or
where
>to find that information please? Thanks!
> The base glaze I am using, SG-5 in Chappell, is:
> Gerstley Borate 51
> Silica 31
> Kaolin 16 (I use EPK)
> Custer Feldspar 3
> Bentonite 1
>
> At cone 4 this fires quite smooth, at cone 5 I get a few small
>blisters with
>copper oxide addition, at cone 6 the blisters become noticeable, at cone 7
they
>go wild! :-(
> I assume the fundamental problem here is oversupply of the flux
Gerstley
>Borate. Is that the case?
> What information have I left out? Thanks in advance for any help!
> Dave Finkelnburg
> dfinkeln@cyberhighway.net
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Ron Roy on sun 28 nov 99
Hi David,
I was trying to do a number of things.
Frit 3134 has 23% boron - GB - has nearly twice as much so I felt I had to
reduce the boron for economic reasons and because I felt there was too
much. I was also concerned because my expansion figures - when using a lot
of boron are unreliable.
When I take out the GB I take out some sodium - to get this back I used a
pot spar - which gives K2O and sodium - and combined alumina and silica and
to help make up some of the alumina that Frit 3134 does not have - and
replace some that comes with the GB that I took out.
Added some Strontium because I know you are looking for a clear glaze and
there are some benefits in terms of melt and durability. Also I think
Strontium is a very useful oxide and everyone should have some. If my
revision works then more potters will get some and our glazes will be the
better for it. More melt means we can include more alumina and silica which
means better durability.
I added the silica and alumina because you said - as you increased the temp
you got more blistering - which probably means your glaze was over fluxed.
Adding alumina and silica is like reducing flux.
There - now you know all my secrets - well a few anyway.
Glad to answer your questions Dave - it's a good distillation process for
me - anyone who has comments - I welcome their opinions.
RR
>----------------------------Original message----------------------------
> I almost didn't ask about this glaze, knowing how you feel about it and
>a certain one of it's ingredients. :-) I do apologize for frustrating you!
>You give so much time and energy to this list regarding glazes. I am sure
>others appreciate what you do as much as I do.
> I have followed your directions as exactly as I could. The test tiles
>are in the kiln now. I'll let you know what they look like tomorrow night.
> In your version, I see you:
> changed about 1/3 of the Na2O to K2O,
> replaced some of the calcium with strontium,
> raised the alumina about 25 mole %, and the silica almost 10%, while
>reducing the boron by 40%.
> Are the alumina/silica changes to increase glaze viscosity? Is the
>strontium to get another source of flux or?
>I am trying to understand why you made the changes you did. Any insight
>into that would be sincerely appreciated.
> Dave Finkelnburg in frosty Idaho
>
>----Original Message-----
>From: Ron Roy
>To: CLAYART@LSV.UKY.EDU
>Date: Tuesday, November 23, 1999 10:45 AM
>Subject: Re: How to make C5 glaze C6?
>
>
>----------------------------Original message----------------------------
>I'm getting tired of dealing with this glaze - I don't like it - I think
>it's dumb and I wish it would go away.
>
>Hi Dave - this is not aimed at you - just some frustratation coming out.
>
>This following recipe is a more balanced glaze - make up 500 grams of it
>and 500 of the original and do a 5 part line blend and tell me what happens
>- please.
>
>Sieve 2 times through 80m.
>
>After dipping in # 1(your original) and #5 (my revision) take equal amount
>of #1 and #5 to make #3 (you will need twice as much of #3 cause you will
>need to mix it with #1 to get #2 and again with #5 to get #4 - equal parts.
>When you have dipped into #2 and #4 mix it all together to get #3. Fire to
>cone 6 (use a large cone beside the tests)
>
>My revision.
>
>Gers Borate - 32.0
>Custer - 28.0
>Wolastonite - 5.0
>Strontium Carb - 3.0
>EPK - 11.0
>Silica - 21.0
>Bentonite - 1.0
>Total - 101.0
>
>There that feels better.
>
>It would be even better if you would let me do this with some frit 3134 -
>then it would be much better.
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Barney Adams on mon 29 nov 99
Hi Ron,
I'm glad to hear this about the Strontium. I try to put a little
in most of my glazes. I usually try to put about 2% of zinc oxide
too. It's mustly to just to add to the melt. I have to tell you I am
working on my ravenscag matt glaze. I'm using strontium and
whiting to bring the melt to ^6. I finally got what I felt was a
reasonable expansion and the si:al ration was pretty low for a
matt. The tests looked good even though I fired to a soft ^7.
I mixed up a bigger batch to see the look on regualr pots. I fired
to a soft ^6 and the pots looked like they had been sprayed with ITC.
I was'nt thinking that the increased alumina affected melt. I was suprised
that the melt point was so close to ^6. I'm going to raise the ratio si:al
and add a smidgeon of zinc oxide. Hopefully the two additions with
balance out the expansion. Oh, I re-fired the load to a hard ^8 and it
looked fine.
I'm using Tucker's mid red and this ravenscag matt is a mauve. I can move
this more toward a white by going with 5-6% zinc oxide or would adding
neph syenite or more whiting help move in this direction?
Barney
Ron Roy wrote:
> ----------------------------Original message----------------------------
> Hi David,
>
> I was trying to do a number of things.
>
> Frit 3134 has 23% boron - GB - has nearly twice as much so I felt I had to
> reduce the boron for economic reasons and because I felt there was too
> much. I was also concerned because my expansion figures - when using a lot
> of boron are unreliable.
>
> When I take out the GB I take out some sodium - to get this back I used a
> pot spar - which gives K2O and sodium - and combined alumina and silica and
> to help make up some of the alumina that Frit 3134 does not have - and
> replace some that comes with the GB that I took out.
>
> Added some Strontium because I know you are looking for a clear glaze and
> there are some benefits in terms of melt and durability. Also I think
> Strontium is a very useful oxide and everyone should have some. If my
> revision works then more potters will get some and our glazes will be the
> better for it. More melt means we can include more alumina and silica which
> means better durability.
>
> I added the silica and alumina because you said - as you increased the temp
> you got more blistering - which probably means your glaze was over fluxed.
> Adding alumina and silica is like reducing flux.
>
> There - now you know all my secrets - well a few anyway.
>
> Glad to answer your questions Dave - it's a good distillation process for
> me - anyone who has comments - I welcome their opinions.
>
> RR
>
> >----------------------------Original message----------------------------
> > I almost didn't ask about this glaze, knowing how you feel about it and
> >a certain one of it's ingredients. :-) I do apologize for frustrating you!
> >You give so much time and energy to this list regarding glazes. I am sure
> >others appreciate what you do as much as I do.
> > I have followed your directions as exactly as I could. The test tiles
> >are in the kiln now. I'll let you know what they look like tomorrow night.
> > In your version, I see you:
> > changed about 1/3 of the Na2O to K2O,
> > replaced some of the calcium with strontium,
> > raised the alumina about 25 mole %, and the silica almost 10%, while
> >reducing the boron by 40%.
> > Are the alumina/silica changes to increase glaze viscosity? Is the
> >strontium to get another source of flux or?
> >I am trying to understand why you made the changes you did. Any insight
> >into that would be sincerely appreciated.
> > Dave Finkelnburg in frosty Idaho
> >
> >----Original Message-----
> >From: Ron Roy
> >To: CLAYART@LSV.UKY.EDU
> >Date: Tuesday, November 23, 1999 10:45 AM
> >Subject: Re: How to make C5 glaze C6?
> >
> >
> >----------------------------Original message----------------------------
> >I'm getting tired of dealing with this glaze - I don't like it - I think
> >it's dumb and I wish it would go away.
> >
> >Hi Dave - this is not aimed at you - just some frustratation coming out.
> >
> >This following recipe is a more balanced glaze - make up 500 grams of it
> >and 500 of the original and do a 5 part line blend and tell me what happens
> >- please.
> >
> >Sieve 2 times through 80m.
> >
> >After dipping in # 1(your original) and #5 (my revision) take equal amount
> >of #1 and #5 to make #3 (you will need twice as much of #3 cause you will
> >need to mix it with #1 to get #2 and again with #5 to get #4 - equal parts.
> >When you have dipped into #2 and #4 mix it all together to get #3. Fire to
> >cone 6 (use a large cone beside the tests)
> >
> >My revision.
> >
> >Gers Borate - 32.0
> >Custer - 28.0
> >Wolastonite - 5.0
> >Strontium Carb - 3.0
> >EPK - 11.0
> >Silica - 21.0
> >Bentonite - 1.0
> >Total - 101.0
> >
> >There that feels better.
> >
> >It would be even better if you would let me do this with some frit 3134 -
> >then it would be much better.
>
> Ron Roy
> 93 Pegasus Trail
> Scarborough
> Ontario, Canada
> M1G 3N8
> Evenings 416-439-2621
> Fax 416-438-7849
Dave Finkelnburg on mon 29 nov 99
Ron,
You wrote: "Also I think Strontium is a very useful oxide and everyone
should have some."
I find very little mention (almost none) of strontium in my reference
materials. Can you please expand on what it is about strontium which makes
it a superior flux oxide? Thanks!
Dave Finkelnburg
dfinkeln@cyberhighway.net
Ron Roy on tue 30 nov 99
Hi Barn,
I don't have an analysis for ravenscrag so I can'r answer - better send it
to me and ask your question again - I'll be out of twon from Thurday till
Sat.
RR
>----------------------------Original message----------------------------
>Hi Ron,
>I'm glad to hear this about the Strontium. I try to put a little
>in most of my glazes. I usually try to put about 2% of zinc oxide
>too. It's mustly to just to add to the melt. I have to tell you I am
>working on my ravenscag matt glaze. I'm using strontium and
>whiting to bring the melt to ^6. I finally got what I felt was a
>reasonable expansion and the si:al ration was pretty low for a
>matt. The tests looked good even though I fired to a soft ^7.
>
>I mixed up a bigger batch to see the look on regualr pots. I fired
>to a soft ^6 and the pots looked like they had been sprayed with ITC.
>I was'nt thinking that the increased alumina affected melt. I was suprised
>that the melt point was so close to ^6. I'm going to raise the ratio si:al
>and add a smidgeon of zinc oxide. Hopefully the two additions with
>balance out the expansion. Oh, I re-fired the load to a hard ^8 and it
>looked fine.
>
>I'm using Tucker's mid red and this ravenscag matt is a mauve. I can move
>this more toward a white by going with 5-6% zinc oxide or would adding
>neph syenite or more whiting help move in this direction?
>
>Barney
>
>Ron Roy wrote:
>
>> ----------------------------Original message----------------------------
>> Hi David,
>>
>> I was trying to do a number of things.
>>
>> Frit 3134 has 23% boron - GB - has nearly twice as much so I felt I had to
>> reduce the boron for economic reasons and because I felt there was too
>> much. I was also concerned because my expansion figures - when using a lot
>> of boron are unreliable.
>>
>> When I take out the GB I take out some sodium - to get this back I used a
>> pot spar - which gives K2O and sodium - and combined alumina and silica and
>> to help make up some of the alumina that Frit 3134 does not have - and
>> replace some that comes with the GB that I took out.
>>
>> Added some Strontium because I know you are looking for a clear glaze and
>> there are some benefits in terms of melt and durability. Also I think
>> Strontium is a very useful oxide and everyone should have some. If my
>> revision works then more potters will get some and our glazes will be the
>> better for it. More melt means we can include more alumina and silica which
>> means better durability.
>>
>> I added the silica and alumina because you said - as you increased the temp
>> you got more blistering - which probably means your glaze was over fluxed.
>> Adding alumina and silica is like reducing flux.
>>
>> There - now you know all my secrets - well a few anyway.
>>
>> Glad to answer your questions Dave - it's a good distillation process for
>> me - anyone who has comments - I welcome their opinions.
>>
>> RR
>>
>> >----------------------------Original message----------------------------
>> > I almost didn't ask about this glaze, knowing how you feel about it and
>> >a certain one of it's ingredients. :-) I do apologize for frustrating you!
>> >You give so much time and energy to this list regarding glazes. I am sure
>> >others appreciate what you do as much as I do.
>> > I have followed your directions as exactly as I could. The test tiles
>> >are in the kiln now. I'll let you know what they look like tomorrow night.
>> > In your version, I see you:
>> > changed about 1/3 of the Na2O to K2O,
>> > replaced some of the calcium with strontium,
>> > raised the alumina about 25 mole %, and the silica almost 10%, while
>> >reducing the boron by 40%.
>> > Are the alumina/silica changes to increase glaze viscosity? Is the
>> >strontium to get another source of flux or?
>> >I am trying to understand why you made the changes you did. Any insight
>> >into that would be sincerely appreciated.
>> > Dave Finkelnburg in frosty Idaho
>> >
>> >----Original Message-----
>> >From: Ron Roy
>> >To: CLAYART@LSV.UKY.EDU
>> >Date: Tuesday, November 23, 1999 10:45 AM
>> >Subject: Re: How to make C5 glaze C6?
>> >
>> >
>> >----------------------------Original message----------------------------
>> >I'm getting tired of dealing with this glaze - I don't like it - I think
>> >it's dumb and I wish it would go away.
>> >
>> >Hi Dave - this is not aimed at you - just some frustratation coming out.
>> >
>> >This following recipe is a more balanced glaze - make up 500 grams of it
>> >and 500 of the original and do a 5 part line blend and tell me what happens
>> >- please.
>> >
>> >Sieve 2 times through 80m.
>> >
>> >After dipping in # 1(your original) and #5 (my revision) take equal amount
>> >of #1 and #5 to make #3 (you will need twice as much of #3 cause you will
>> >need to mix it with #1 to get #2 and again with #5 to get #4 - equal parts.
>> >When you have dipped into #2 and #4 mix it all together to get #3. Fire to
>> >cone 6 (use a large cone beside the tests)
>> >
>> >My revision.
>> >
>> >Gers Borate - 32.0
>> >Custer - 28.0
>> >Wolastonite - 5.0
>> >Strontium Carb - 3.0
>> >EPK - 11.0
>> >Silica - 21.0
>> >Bentonite - 1.0
>> >Total - 101.0
>> >
>> >There that feels better.
>> >
>> >It would be even better if you would let me do this with some frit 3134 -
>> >then it would be much better.
>>
>> Ron Roy
>> 93 Pegasus Trail
>> Scarborough
>> Ontario, Canada
>> M1G 3N8
>> Evenings 416-439-2621
>> Fax 416-438-7849
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Ron Roy on wed 1 dec 99
There are various attributes attached to each oxide - some for Strontium
are - improves gloss and aids in making a glaze more durable - but that is
not the main reason. Having more fluxes in a glaze helps it melt more -
this means more silica and alumina can be added and that is a definite plus
when durability is a factor. Even adding a small amount of another flux has
an effect.
Having more fluxes in any glaze has an advantage.
You could prove this out by finding a c6 glaze that did not have any zinc,
barium and strontium - add 1% of each to it and then see how much more
silica and alumina you could get in and have it look the same. This will
help with crazing as well.
RR
>----------------------------Original message----------------------------
>Ron,
> You wrote: "Also I think Strontium is a very useful oxide and everyone
>should have some."
> I find very little mention (almost none) of strontium in my reference
>materials. Can you please expand on what it is about strontium which makes
>it a superior flux oxide? Thanks!
> Dave Finkelnburg
> dfinkeln@cyberhighway.net
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Barney Adams on wed 1 dec 99
Ron Roy wrote:
> ----------------------------Original message----------------------------
> Hi Barn,
>
> I don't have an analysis for ravenscrag so I can'r answer - better send it
> to me and ask your question again - I'll be out of twon from Thurday till
> Sat.
>
> RR
Hi Ron,
I did'nt mean to bother you with this. Iwas looking for a hint in the approach.
I guess I was'nt being fair not giving you all the info.
This is the analysis I got from Plainsman on Ravenscag.
CaO 5.2
K2O 3.5
MgO 2.1
Na2O 0.5
TiO2 0.4
Al2O3 14.7
P2O5 0.0
SiO2 72.5
Fe2O3 0.9
LOI 4.6%
The way I have this in the MDT of Insight looks like this (in case I screwed
something up)
CaO 0.488 5.3%
MgO 0.274 2.1%
K2O 0.196 3.5%
Na2O 0.042 0.5%
TiO2 0.026 0.4%
Al2O3 0.758 14.9%
SiO2 6.359 73.3%
Here's my first attempt the melt is more along the ^8 area than ^6.
I was trying for a low Si:Al ratio and went too low.
Ravenscag matt #1
=================
Ravenscag Slip...... 50.00 50.00%
STRONTIUM CARBONATE. 14.00 14.00%
WHITING............. 10.00 10.00%
GROLLEG KAOLIN...... 26.00 26.00%
========
100.00
CaO 0.50* 9.25%
MgO 0.10* 1.32%
K2O 0.07* 2.09%
Na2O 0.02* 0.32%
Fe2O3 0.00 0.22%
TIO2 0.01 0.24%
AL2O3 0.57 19.50%
SiO2 2.80 55.92%
SrO 0.32* 11.14%
COST/KG 2.59
Si:Al 4.88
SiB:Al 4.88
EXPAN462.04
This is a nice matt on the Tucker Smooth White when it melts.
On the Mid Red body it goes a matt mauve color. Not bad but I was
hoping for it to go more toward white. I was trying to keep it simple
and kept away from my big box of GB. :->
I was thinking of 3 possible ways to make the glaze tend toward white.
1) zinc oxide
2) more whiting
3) Neph Syenite or custer spar
The whiting or zinc oxide as I understand them promote crystal growth that can t
toward white?
The neph syenite and custer tend to melt white?
Or am I all wrong in this. Would going with TiO2 be a more direct approach?
I'm not looking for the color to be white in itself, but I'd like to move from a
mauve.
No hurry, when you get back will be fine.
Barney
Evan Dresel on wed 1 dec 99
I really appreciate Ron elaborating on his thought process when
reformulating this glaze. This is a great help in learning how to apply
glaze calculation.
I'm interested in the strontium part. I thought that strontium was
similar in its effect to calcium, or maybe somewhat between calcium and
barium given it's place on the periodic table. So I'm not sure why it
is useful in a clear glaze. I thought it's main use was to replace
barium in a mat glaze when you don't want the possible hazard of the
barium and can handle the impact on colorants. So what does strontium
do for you in a clear glaze that calcium won't?
Thanks for the enlightenment.
-- Evan in W. Richland WA who's dalmatian, Stella, thinks she makes a
perfectly good lap cat, to the chagrin of the true cats, Pippistrelle,
and Carbide.
Ron Roy wrote:
>
> ----------------------------Original message----------------------------
> Hi David,
>
> I was trying to do a number of things.
>
> Frit 3134 has 23% boron - GB - has nearly twice as much so I felt I had to
> reduce the boron for economic reasons and because I felt there was too
> much. I was also concerned because my expansion figures - when using a lot
> of boron are unreliable.
>
> When I take out the GB I take out some sodium - to get this back I used a
> pot spar - which gives K2O and sodium - and combined alumina and silica and
> to help make up some of the alumina that Frit 3134 does not have - and
> replace some that comes with the GB that I took out.
>
> Added some Strontium because I know you are looking for a clear glaze and
> there are some benefits in terms of melt and durability. Also I think
> Strontium is a very useful oxide and everyone should have some. If my
> revision works then more potters will get some and our glazes will be the
> better for it. More melt means we can include more alumina and silica which
> means better durability.
>
> I added the silica and alumina because you said - as you increased the temp
> you got more blistering - which probably means your glaze was over fluxed.
> Adding alumina and silica is like reducing flux.
>
> There - now you know all my secrets - well a few anyway.
>
> Glad to answer your questions Dave - it's a good distillation process for
> me - anyone who has comments - I welcome their opinions.
>
> RR
>
> >----------------------------Original message----------------------------
> > I almost didn't ask about this glaze, knowing how you feel about it and
> >a certain one of it's ingredients. :-) I do apologize for frustrating you!
> >You give so much time and energy to this list regarding glazes. I am sure
> >others appreciate what you do as much as I do.
> > I have followed your directions as exactly as I could. The test tiles
> >are in the kiln now. I'll let you know what they look like tomorrow night.
> > In your version, I see you:
> > changed about 1/3 of the Na2O to K2O,
> > replaced some of the calcium with strontium,
> > raised the alumina about 25 mole %, and the silica almost 10%, while
> >reducing the boron by 40%.
> > Are the alumina/silica changes to increase glaze viscosity? Is the
> >strontium to get another source of flux or?
> >I am trying to understand why you made the changes you did. Any insight
> >into that would be sincerely appreciated.
> > Dave Finkelnburg in frosty Idaho
> >
> >----Original Message-----
> >From: Ron Roy
> >To: CLAYART@LSV.UKY.EDU
> >Date: Tuesday, November 23, 1999 10:45 AM
> >Subject: Re: How to make C5 glaze C6?
> >
> >
> >----------------------------Original message----------------------------
> >I'm getting tired of dealing with this glaze - I don't like it - I think
> >it's dumb and I wish it would go away.
> >
> >Hi Dave - this is not aimed at you - just some frustratation coming out.
> >
> >This following recipe is a more balanced glaze - make up 500 grams of it
> >and 500 of the original and do a 5 part line blend and tell me what happens
> >- please.
> >
> >Sieve 2 times through 80m.
> >
> >After dipping in # 1(your original) and #5 (my revision) take equal amount
> >of #1 and #5 to make #3 (you will need twice as much of #3 cause you will
> >need to mix it with #1 to get #2 and again with #5 to get #4 - equal parts.
> >When you have dipped into #2 and #4 mix it all together to get #3. Fire to
> >cone 6 (use a large cone beside the tests)
> >
> >My revision.
> >
> >Gers Borate - 32.0
> >Custer - 28.0
> >Wolastonite - 5.0
> >Strontium Carb - 3.0
> >EPK - 11.0
> >Silica - 21.0
> >Bentonite - 1.0
> >Total - 101.0
> >
> >There that feels better.
> >
> >It would be even better if you would let me do this with some frit 3134 -
> >then it would be much better.
>
> Ron Roy
> 93 Pegasus Trail
> Scarborough
> Ontario, Canada
> M1G 3N8
> Evenings 416-439-2621
> Fax 416-438-7849
Ron Roy on thu 2 dec 99
Hi Evan,
This has to be short - I'm leaving to do a workshop tomorrow and it's late.
Perhaps others will explain the use of extra fluxes in a glaze -
complicated glazes melt better, having too much of one flux is not good for
durability - like too much CaO?
Yes Strontium is a middle rage flux - like Barium, Calcium, Zinc and Magnesium.
Say you needed to lower expansion - you could add some strontium at the
expense of KNaO for instance - it would work in some glazes.
If you had .60 moles of Calcium and you replaced some with say 0.1 of
Strontium you would get more melt and most glazes would still look the same
but melt better and/or you could then add more alumina and silica if
needed.
It is an easy material to use - for instance adding a little to a cone 6
glaze that was not melting quite enough might just do the trick and it
would not affect the ratio at all.
Gotta go - let me know if you want more on this Evan - I'll be bach on Sat.
RR
>----------------------------Original message----------------------------
>I really appreciate Ron elaborating on his thought process when
>reformulating this glaze. This is a great help in learning how to apply
>glaze calculation.
>
>I'm interested in the strontium part. I thought that strontium was
>similar in its effect to calcium, or maybe somewhat between calcium and
>barium given it's place on the periodic table. So I'm not sure why it
>is useful in a clear glaze. I thought it's main use was to replace
>barium in a mat glaze when you don't want the possible hazard of the
>barium and can handle the impact on colorants. So what does strontium
>do for you in a clear glaze that calcium won't?
>
>Thanks for the enlightenment.
>
>-- Evan in W. Richland WA who's dalmatian, Stella, thinks she makes a
>perfectly good lap cat, to the chagrin of the true cats, Pippistrelle,
>and Carbide.
>
>Ron Roy wrote:
>>
>> ----------------------------Original message----------------------------
>> Hi David,
>>
>> I was trying to do a number of things.
>>
>> Frit 3134 has 23% boron - GB - has nearly twice as much so I felt I had to
>> reduce the boron for economic reasons and because I felt there was too
>> much. I was also concerned because my expansion figures - when using a lot
>> of boron are unreliable.
>>
>> When I take out the GB I take out some sodium - to get this back I used a
>> pot spar - which gives K2O and sodium - and combined alumina and silica and
>> to help make up some of the alumina that Frit 3134 does not have - and
>> replace some that comes with the GB that I took out.
>>
>> Added some Strontium because I know you are looking for a clear glaze and
>> there are some benefits in terms of melt and durability. Also I think
>> Strontium is a very useful oxide and everyone should have some. If my
>> revision works then more potters will get some and our glazes will be the
>> better for it. More melt means we can include more alumina and silica which
>> means better durability.
>>
>> I added the silica and alumina because you said - as you increased the temp
>> you got more blistering - which probably means your glaze was over fluxed.
>> Adding alumina and silica is like reducing flux.
>>
>> There - now you know all my secrets - well a few anyway.
>>
>> Glad to answer your questions Dave - it's a good distillation process for
>> me - anyone who has comments - I welcome their opinions.
>>
>> RR
>>
>> >----------------------------Original message----------------------------
>> > I almost didn't ask about this glaze, knowing how you feel about it and
>> >a certain one of it's ingredients. :-) I do apologize for frustrating you!
>> >You give so much time and energy to this list regarding glazes. I am sure
>> >others appreciate what you do as much as I do.
>> > I have followed your directions as exactly as I could. The test tiles
>> >are in the kiln now. I'll let you know what they look like tomorrow night.
>> > In your version, I see you:
>> > changed about 1/3 of the Na2O to K2O,
>> > replaced some of the calcium with strontium,
>> > raised the alumina about 25 mole %, and the silica almost 10%, while
>> >reducing the boron by 40%.
>> > Are the alumina/silica changes to increase glaze viscosity? Is the
>> >strontium to get another source of flux or?
>> >I am trying to understand why you made the changes you did. Any insight
>> >into that would be sincerely appreciated.
>> > Dave Finkelnburg in frosty Idaho
>> >
>> >----Original Message-----
>> >From: Ron Roy
>> >To: CLAYART@LSV.UKY.EDU
>> >Date: Tuesday, November 23, 1999 10:45 AM
>> >Subject: Re: How to make C5 glaze C6?
>> >
>> >
>> >----------------------------Original message----------------------------
>> >I'm getting tired of dealing with this glaze - I don't like it - I think
>> >it's dumb and I wish it would go away.
>> >
>> >Hi Dave - this is not aimed at you - just some frustratation coming out.
>> >
>> >This following recipe is a more balanced glaze - make up 500 grams of it
>> >and 500 of the original and do a 5 part line blend and tell me what happens
>> >- please.
>> >
>> >Sieve 2 times through 80m.
>> >
>> >After dipping in # 1(your original) and #5 (my revision) take equal amount
>> >of #1 and #5 to make #3 (you will need twice as much of #3 cause you will
>> >need to mix it with #1 to get #2 and again with #5 to get #4 - equal parts.
>> >When you have dipped into #2 and #4 mix it all together to get #3. Fire to
>> >cone 6 (use a large cone beside the tests)
>> >
>> >My revision.
>> >
>> >Gers Borate - 32.0
>> >Custer - 28.0
>> >Wolastonite - 5.0
>> >Strontium Carb - 3.0
>> >EPK - 11.0
>> >Silica - 21.0
>> >Bentonite - 1.0
>> >Total - 101.0
>> >
>> >There that feels better.
>> >
>> >It would be even better if you would let me do this with some frit 3134 -
>> >then it would be much better.
>>
>> Ron Roy
>> 93 Pegasus Trail
>> Scarborough
>> Ontario, Canada
>> M1G 3N8
>> Evenings 416-439-2621
>> Fax 416-438-7849
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Ron Roy on mon 6 dec 99
Hi Barney,
Thanks for the analysis - but - the total is 104.4 - now I can see how an
analysis can be less then 100 but how can it be more? Good question for
Tony Hansen I guess.
The mauve is coming from the iron in the mid red body - I wonder if
additions of zirconium silicate (zircopax, superpax, ultrox) would do the
trick. It will help with recrystalization as well - try 5 and 10% to start
with. If it gets too dry you can use some Neph Sy but not too much - you
might get into deflocculated glaze in the bucket - it's a good choice for a
matte because it has a lot of alumina and is short of silica (compared to
spars.)
Better test it thicker - that colour may be just too thin a coat.
RR
>----------------------------Original message----------------------------
>Hi Ron,
>I did'nt mean to bother you with this. Iwas looking for a hint in the approach.
>I guess I was'nt being fair not giving you all the info.
>
>This is the analysis I got from Plainsman on Ravenscag.
>
>CaO 5.2
>K2O 3.5
>MgO 2.1
>Na2O 0.5
>TiO2 0.4
>Al2O3 14.7
>P2O5 0.0
>SiO2 72.5
>Fe2O3 0.9
>LOI 4.6%
>
>The way I have this in the MDT of Insight looks like this (in case I screwed
>something up)
>
>CaO 0.488 5.3%
>MgO 0.274 2.1%
>K2O 0.196 3.5%
>Na2O 0.042 0.5%
>TiO2 0.026 0.4%
>Al2O3 0.758 14.9%
>SiO2 6.359 73.3%
>
>Here's my first attempt the melt is more along the ^8 area than ^6.
>I was trying for a low Si:Al ratio and went too low.
>
>Ravenscag matt #1
>=================
> Ravenscag Slip...... 50.00 50.00%
> STRONTIUM CARBONATE. 14.00 14.00%
> WHITING............. 10.00 10.00%
> GROLLEG KAOLIN...... 26.00 26.00%
> ========
> 100.00
>
> CaO 0.50* 9.25%
> MgO 0.10* 1.32%
> K2O 0.07* 2.09%
> Na2O 0.02* 0.32%
> Fe2O3 0.00 0.22%
> TIO2 0.01 0.24%
> AL2O3 0.57 19.50%
> SiO2 2.80 55.92%
> SrO 0.32* 11.14%
>
> COST/KG 2.59
> Si:Al 4.88
> SiB:Al 4.88
> EXPAN462.04
>
>This is a nice matt on the Tucker Smooth White when it melts.
>On the Mid Red body it goes a matt mauve color. Not bad but I was
>hoping for it to go more toward white. I was trying to keep it simple
>and kept away from my big box of GB. :->
>
>I was thinking of 3 possible ways to make the glaze tend toward white.
>1) zinc oxide
>2) more whiting
>3) Neph Syenite or custer spar
>
>
>The whiting or zinc oxide as I understand them promote crystal growth that
>can t
>toward white?
>The neph syenite and custer tend to melt white?
>
>Or am I all wrong in this. Would going with TiO2 be a more direct approach?
>I'm not looking for the color to be white in itself, but I'd like to move
>from a
>mauve.
>
>No hurry, when you get back will be fine.
>Barney
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Barney Adams on tue 7 dec 99
Thanks Ron,
I had just read that the CaO only works for a white when the alumina is low.
I have some zircopax, but I'll try thicker coat on next firing. I can live with
mauve
if it would break white were thick.
Barney
Ron Roy wrote:
> ----------------------------Original message----------------------------
> Hi Barney,
>
> Thanks for the analysis - but - the total is 104.4 - now I can see how an
> analysis can be less then 100 but how can it be more? Good question for
> Tony Hansen I guess.
>
> The mauve is coming from the iron in the mid red body - I wonder if
> additions of zirconium silicate (zircopax, superpax, ultrox) would do the
> trick. It will help with recrystalization as well - try 5 and 10% to start
> with. If it gets too dry you can use some Neph Sy but not too much - you
> might get into deflocculated glaze in the bucket - it's a good choice for a
> matte because it has a lot of alumina and is short of silica (compared to
> spars.)
>
> Better test it thicker - that colour may be just too thin a coat.
>
> RR
>
> >----------------------------Original message----------------------------
> >Hi Ron,
> >I did'nt mean to bother you with this. Iwas looking for a hint in the approac
> >I guess I was'nt being fair not giving you all the info.
> >
> >This is the analysis I got from Plainsman on Ravenscag.
> >
> >CaO 5.2
> >K2O 3.5
> >MgO 2.1
> >Na2O 0.5
> >TiO2 0.4
> >Al2O3 14.7
> >P2O5 0.0
> >SiO2 72.5
> >Fe2O3 0.9
> >LOI 4.6%
> >
> >The way I have this in the MDT of Insight looks like this (in case I screwed
> >something up)
> >
> >CaO 0.488 5.3%
> >MgO 0.274 2.1%
> >K2O 0.196 3.5%
> >Na2O 0.042 0.5%
> >TiO2 0.026 0.4%
> >Al2O3 0.758 14.9%
> >SiO2 6.359 73.3%
> >
> >Here's my first attempt the melt is more along the ^8 area than ^6.
> >I was trying for a low Si:Al ratio and went too low.
> >
> >Ravenscag matt #1
> >=================
> > Ravenscag Slip...... 50.00 50.00%
> > STRONTIUM CARBONATE. 14.00 14.00%
> > WHITING............. 10.00 10.00%
> > GROLLEG KAOLIN...... 26.00 26.00%
> > ========
> > 100.00
> >
> > CaO 0.50* 9.25%
> > MgO 0.10* 1.32%
> > K2O 0.07* 2.09%
> > Na2O 0.02* 0.32%
> > Fe2O3 0.00 0.22%
> > TIO2 0.01 0.24%
> > AL2O3 0.57 19.50%
> > SiO2 2.80 55.92%
> > SrO 0.32* 11.14%
> >
> > COST/KG 2.59
> > Si:Al 4.88
> > SiB:Al 4.88
> > EXPAN462.04
> >
> >This is a nice matt on the Tucker Smooth White when it melts.
> >On the Mid Red body it goes a matt mauve color. Not bad but I was
> >hoping for it to go more toward white. I was trying to keep it simple
> >and kept away from my big box of GB. :->
> >
> >I was thinking of 3 possible ways to make the glaze tend toward white.
> >1) zinc oxide
> >2) more whiting
> >3) Neph Syenite or custer spar
> >
> >
> >The whiting or zinc oxide as I understand them promote crystal growth that
> >can t
> >toward white?
> >The neph syenite and custer tend to melt white?
> >
> >Or am I all wrong in this. Would going with TiO2 be a more direct approach?
> >I'm not looking for the color to be white in itself, but I'd like to move
> >from a
> >mauve.
> >
> >No hurry, when you get back will be fine.
> >Barney
>
> Ron Roy
> 93 Pegasus Trail
> Scarborough
> Ontario, Canada
> M1G 3N8
> Evenings 416-439-2621
> Fax 416-438-7849
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