gambaru on tue 11 nov 97
Tony Hansen has published a cone 57 base glaze and cone 10 glossy and
silky matte base receipe. Could you alter the cone 10 silkly matte for
reduction firing at cone 67 ? Receipe: G2571A Silky Matte Base Receipe
from Tony Hansen :
5.50 Wollastonite
28.50 Custer Feldspar (G200 is what we have available)
28.00 EPK
15.00 Flint
19.00 Dolomite
4.00 Gerstley Borate
Thanks a bunch. I am curious about the pathways that you use to arrive at
a glaze that would be close in appearance, fit and durablility. M.B.
Ron Roy on fri 14 nov 97
Big question and not enough time  it will just have to be quick and simple.
From the molecular formula try to figure out why this glaze is what it is 
if you don't know what each oxide does in the glaze then start reading
everything you can get your hands on  it's what the individual oxides do
that you need to know.
Significant points:
MgO high
Alumina: high in relation to silica (nearly a matte glaze)
Some boron
Expansion on low side
Ratio 5.51 silica to 1 alumina (important to keep this at least similar)
The quick way to do this would be to take out (bit by bit) some of the clay
and reduce the silica at the same time to keep the ratio the same. This
would lead to high expansion very quickly so  not the best solution.
Increasing some fluxes will have the same result but have to choose fluxes
with low expansion  lets try boron  lets use a frit  which one.
There is plenty of clay here already  use a frit with some alumina in.
Don't want too much boron cause we will probably lose the "silky matte"
surface  looks like 3124 might work  and it's the cheapest.
Do #1 by adding 5.0 F3124 then lower silica to 14 to get back to right
ratio  recalculate glaze to add up to 100.
#2 add 10.0 F3124 (to the original)  lower silica to 13 to get ratio back
to about 5.50  recalculate glaze to add up to 100.
#3 add 15.0 F3124  lower silica to 11.5 ............ Etc.
#4 add 20.0 F3124  lower silica to 10.5
Always mix at least 200 grams per test  500 would be better. Balance your
scales before you start  sieve all tests through 80 mesh  twice. Always
fire tests upright and ALWAYS have a LARGE cone near them. At least freeze
them to pick up any fit problems  dipping the frozen tests in boiling
water will tell you even more. If there are fit problems lurking they may
show up on bigger pieces so keep checking if you decide to use a new glaze.
If you change bodies you will have changed the relationship between glaze
and clay  don't assume fit problems are not there  find out by testing.
The expansion increases but it started low so even #4 will still not craze
on many bodies.
Be aware  this c10 glaze started out short of silica so durability could
be a problem. #4 is probably a more durable glaze than the original but it
still might not be melting well enough. If you start adding other fluxes
choose those with low expansions like MgO, ZnO and B2O3 which has the
lowest. If you add fluxes to #4 the silica will end up short so durability
will be affected. If a glaze has more than 12% boron (#4 has 3.81% so this
is not a factor here) the low expansion begins to get higher.
How you alter a glaze is dictated by what you want at the other end. Color
response, texture, melt, durability, fit, opacity and viscosity are all
controlled by the individual oxides in a glaze  if you don't understand
any of the terms I am using you need to educate yourself. I recommend
calculation software and the best library you can afford. The first book I
recommend you get is the Hamer dictionary.
I hope this is a good start for you  maybe there is a need for an Email
correspondence course on the subject  anyone interested in that?
>Original message
>Tony Hansen has published a cone 57 base glaze and cone 10 glossy and
>silky matte base receipe. Could you alter the cone 10 silkly matte for
>reduction firing at cone 67 ? Receipe: G2571A Silky Matte Base Receipe
>from Tony Hansen :
>
>5.50 Wollastonite
>28.50 Custer Feldspar (G200 is what we have available)
>28.00 EPK
>15.00 Flint
>19.00 Dolomite
> 4.00 Gerstley Borate
>
>Thanks a bunch. I am curious about the pathways that you use to arrive at
>a glaze that would be close in appearance, fit and durablility. M.B.
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 4167527862.
Email ronroy@astral.magic.ca
Home page http://digitalfire.com/education/people/ronroy.htm
Robert Santerre on sun 16 nov 97
Ron, although your comments were very succinct they were, in fact, an =
excellent
short course (very short) on how one can approach the problem of converting =
a
=5E10 glaze to =5E6, a problem that many of us have considered from time to =
time but
walked away from because most texts don't deal with the problem adequately =
or
conversely have such technical depth that you need three years of chem E to =
make
any sense of it. I think your comment about an email course has a lot of
merit. While I'm not sure about the mechanics of an email course per se, I
have been impressed with some of the selfpaced, interactive computer =
courses
I've taken. Some of them are pretty darn good, getting you quickly to a =
point
where you can use the basic features of the application well and providing a
platform for learning advanced features on your own. Why couldn't someone =
(you,
Tony Hansen, etc.) put together such a computerbased course for glaze
chemistry (perhaps a poor choice of terms, call it =22Getting to know =
glazes=22,
=22The how tos of ceramic glazing=22, whatever) oriented toward problem =
solving
(shivering, crazing, food safety, color development, etc.). I can't really
appreciate the difficulty of putting together such a course, but I =
absolutely
know the market for it would be huge. Maybe it could be setup as a =
webbased
application. One could download the course application for a fee and =
questions
could be directed to the web site (that would take a bit of someone's time =
to
keep up with), there could be a FAQs section, links to other ceramic =
resources
on the web, etc. Maybe it could be packaged up with Insight? For example, =
I
have Insight, but frankly my glaze chemistry knowledge is so lacking that I
can't really use it to solve problems  there's clearly a giant leap between
limit formulas and figuring out what adjustments to make to solve a =
shivering
(or whatever) problem. I imagine it would be quite a bit of work to put
together such a course, but I'm convinced it
could be done. The positive comments I've read about the glaze course you
teach suggest you've got a great start on it. How about it, did I hear you
volunteer?
Fellow Clayarters, =22What do you think?=22 How many of you would be =
interested in
taking such a course if it were available? Would you be willing to spend =
hard
cash for it? What features would you like to see in such a course?
Bob
rfsanterre=40iquest.net
////////////////////////////////////////////////////////////////////////////=
////
/////////////////////////

From: Ron Roy=5BSMTP:ronroy=40astral.magic.ca=5D
Sent: Friday, November 14, 1997 3:59 PM
To: Multiple recipients of list CLAYART
Subject: Re: ron roy,tony hansen c10 to6
Original message
Big question and not enough time  it will just have to be quick and simple.
=3EFrom the molecular formula try to figure out why this glaze is what it is=

if you don't know what each oxide does in the glaze then start reading
everything you can get your hands on  it's what the individual oxides do
that you need to know.
Significant points:
MgO high
Alumina: high in relation to silica (nearly a matte glaze)
Some boron
Expansion on low side
Ratio 5.51 silica to 1 alumina (important to keep this at least similar)
The quick way to do this would be to take out (bit by bit) some of the clay
and reduce the silica at the same time to keep the ratio the same. This
would lead to high expansion very quickly so  not the best solution.
Increasing some fluxes will have the same result but have to choose fluxes
with low expansion  lets try boron  lets use a frit  which one.
There is plenty of clay here already  use a frit with some alumina in.
Don't want too much boron cause we will probably lose the =22silky matte=22
surface  looks like 3124 might work  and it's the cheapest.
Do =231 by adding 5.0 F3124 then lower silica to 14 to get back to right
ratio  recalculate glaze to add up to 100.
=232 add 10.0 F3124 (to the original)  lower silica to 13 to get ratio back
to about 5.50  recalculate glaze to add up to 100.
=233 add 15.0 F3124  lower silica to 11.5 ............ Etc.
=234 add 20.0 F3124  lower silica to 10.5
Always mix at least 200 grams per test  500 would be better. Balance your
scales before you start  sieve all tests through 80 mesh  twice. Always
fire tests upright and ALWAYS have a LARGE cone near them. At least freeze
them to pick up any fit problems  dipping the frozen tests in boiling
water will tell you even more. If there are fit problems lurking they may
show up on bigger pieces so keep checking if you decide to use a new glaze.
If you change bodies you will have changed the relationship between glaze
and clay  don't assume fit problems are not there  find out by testing.
The expansion increases but it started low so even =234 will still not craze
on many bodies.
Be aware  this c10 glaze started out short of silica so durability could
be a problem. =234 is probably a more durable glaze than the original but it
still might not be melting well enough. If you start adding other fluxes
choose those with low expansions like MgO, ZnO and B2O3 which has the
lowest. If you add fluxes to =234 the silica will end up short so durability
will be affected. If a glaze has more than 12=25 boron (=234 has 3.81=25 so =
this
is not a factor here) the low expansion begins to get higher.
How you alter a glaze is dictated by what you want at the other end. Color
response, texture, melt, durability, fit, opacity and viscosity are all
controlled by the individual oxides in a glaze  if you don't understand
any of the terms I am using you need to educate yourself. I recommend
calculation software and the best library you can afford. The first book I
recommend you get is the Hamer dictionary.
I hope this is a good start for you  maybe there is a need for an Email
correspondence course on the subject  anyone interested in that?
=3EOriginal message
=3ETony Hansen has published a cone 57 base glaze and cone 10 glossy and
=3Esilky matte base receipe. Could you alter the cone 10 silkly matte for
=3Ereduction firing at cone 67 ? Receipe: G2571A Silky Matte Base Receipe
=3Efrom Tony Hansen :
=3E
=3E5.50 Wollastonite
=3E28.50 Custer Feldspar (G200 is what we have available)
=3E28.00 EPK
=3E15.00 Flint
=3E19.00 Dolomite
=3E 4.00 Gerstley Borate
=3E
=3EThanks a bunch. I am curious about the pathways that you use to arrive =
at
=3Ea glaze that would be close in appearance, fit and durablility. M.B.
Ron Roy
93 Pegasus Trail
Scarborough,Canada
M1G 3N8
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 4167527862.
Email ronroy=40astral.magic.ca
Home page http://digitalfire.com/education/people/ronroy.htm
Kris Baum on mon 17 nov 97
I'd sign up in a minute, and pay cold hard cash, too. I saw a test
copy of Insight, but never purchased it because I was too ignorant to
use it! Seriously, I didn't have enough knowledge to understand what
I should shoot for in terms of limit formulae. Like the joke  I
don't know where I'm going but I can get there REALLY fast! Speedy
calculations, but I ended up with ??? who knows what! Anyone else
want to encourage the glaze gurus in a new venture?
Bob Santerre wrote:
> Ron, ... I think your comment about an email course has a lot of
merit. ... Why couldn't someone (you, Tony Hansen, etc.) put
together such a computerbased course for glaze chemistry... One
could download the course application for a fee... The positive
comments I've read about the glaze course you teach suggest you've
got a great start on it. How about it, did I hear you volunteer?...
Fellow Clayarters, "What do you think?" How many of you would be
interested in taking such a course if it were available? Would you
be willing to spend hard cash for it? What features would you like
to see in such a course?
> Bob
> rfsanterre@iquest.net
>
> //////////////////////////////////////////////////////////////////////////////
> /////////////////////////
> 
> From: Ron Roy[SMTP:ronroy@astral.magic.ca]
> Sent: Friday, November 14, 1997 3:59 PM
> To: Multiple recipients of list CLAYART
> Subject: Re: ron roy,tony hansen c10 to6
>
> Original message
> Big question and not enough time  it will just have to be quick and simple.
>
> >From the molecular formula try to figure out why this glaze is what it is 
> if you don't know what each oxide does in the glaze then start reading
> everything you can get your hands on  it's what the individual oxides do
> that you need to know.
>
> Significant points:
>
> MgO high
> Alumina: high in relation to silica (nearly a matte glaze)
> Some boron
> Expansion on low side
> Ratio 5.51 silica to 1 alumina (important to keep this at least similar)
>
> The quick way to do this would be to take out (bit by bit) some of the clay
> and reduce the silica at the same time to keep the ratio the same. This
> would lead to high expansion very quickly so  not the best solution.
>
> Increasing some fluxes will have the same result but have to choose fluxes
> with low expansion  lets try boron  lets use a frit  which one.
>
> There is plenty of clay here already  use a frit with some alumina in.
> Don't want too much boron cause we will probably lose the "silky matte"
> surface  looks like 3124 might work  and it's the cheapest.
>
> Do #1 by adding 5.0 F3124 then lower silica to 14 to get back to right
> ratio  recalculate glaze to add up to 100.
>
> #2 add 10.0 F3124 (to the original)  lower silica to 13 to get ratio back
> to about 5.50  recalculate glaze to add up to 100.
>
> #3 add 15.0 F3124  lower silica to 11.5 ............ Etc.
>
> #4 add 20.0 F3124  lower silica to 10.5
>
> Always mix at least 200 grams per test  500 would be better. Balance your
> scales before you start  sieve all tests through 80 mesh  twice. Always
> fire tests upright and ALWAYS have a LARGE cone near them. At least freeze
> them to pick up any fit problems  dipping the frozen tests in boiling
> water will tell you even more. If there are fit problems lurking they may
> show up on bigger pieces so keep checking if you decide to use a new glaze.
> If you change bodies you will have changed the relationship between glaze
> and clay  don't assume fit problems are not there  find out by testing.
>
> The expansion increases but it started low so even #4 will still not craze
> on many bodies.
>
> Be aware  this c10 glaze started out short of silica so durability could
> be a problem. #4 is probably a more durable glaze than the original but it
> still might not be melting well enough. If you start adding other fluxes
> choose those with low expansions like MgO, ZnO and B2O3 which has the
> lowest. If you add fluxes to #4 the silica will end up short so durability
> will be affected. If a glaze has more than 12% boron (#4 has 3.81% so this
> is not a factor here) the low expansion begins to get higher.
>
> How you alter a glaze is dictated by what you want at the other end. Color
> response, texture, melt, durability, fit, opacity and viscosity are all
> controlled by the individual oxides in a glaze  if you don't understand
> any of the terms I am using you need to educate yourself. I recommend
> calculation software and the best library you can afford. The first book I
> recommend you get is the Hamer dictionary.
>
> I hope this is a good start for you  maybe there is a need for an Email
> correspondence course on the subject  anyone interested in that?
>
>
> >Original message
> >Tony Hansen has published a cone 57 base glaze and cone 10 glossy and
> >silky matte base receipe. Could you alter the cone 10 silkly matte for
> >reduction firing at cone 67 ? Receipe: G2571A Silky Matte Base Receipe
> >from Tony Hansen :
> >
> >5.50 Wollastonite
> >28.50 Custer Feldspar (G200 is what we have available)
> >28.00 EPK
> >15.00 Flint
> >19.00 Dolomite
> > 4.00 Gerstley Borate
> >
> >Thanks a bunch. I am curious about the pathways that you use to arrive at
> >a glaze that would be close in appearance, fit and durablility. M.B.
>
> Ron Roy
> 93 Pegasus Trail
> Scarborough,Canada
> M1G 3N8
> Evenings, call 416 439 2621
> Fax, 416 438 7849
> Studio: 4167527862.
> Email ronroy@astral.magic.ca
> Home page http://digitalfire.com/education/people/ronroy.htm
>
>
===============================================
Kris Baum, Shubunkin Pottery
mailto:shubunki@erols.com
===============================================
 
