Mary Back on fri 28 oct 05
I have been making pottery for many years but never mixed my own glazes. I
just attended Clay Connections at Front Royal and a potter demonstrated
some wonderful pieces glazed with Randy's Red Glaze. I found the formula
on the internet but can not determine all the components and would like
some help so that I can buy the material and mix the glaze successfully.
Unity Formula for Randy's Red:
0.046 K20 0.189 Al2O3 2.886 SiO2
0.135 Na2O 0.376 B2O3 0.001 TiO2
0.404 CaO 0.004 Fe2O3
0.416 MgO 0.000 P2O5
15.3:1 Si:Al Ratio
The first column has a bracket pointing to the middle column and the last
column on the right has a bracket pointing to the middle.
I know that
K2O is Potassuim Oxide
Na2O is Borax
CaO is Calcium Oxide
MgO is Magnesium Oxide
Al2O3 is Boric Oxide
B2O3 is Boric Oxide
Fe2O3 is Iron Oxide
P2O5 ??????? can't find
SiO2 is Silica, Flint, Quartz
TiO2 is Titanium Oxide
I guess that the numbers means percentage? or grams?
And I read that Al2O3 and SiO2 is clay? then do I need Silica?
Lots of questions but it is important to me to find out how to buy and mix
this glaze. It is beautiful!!!!! Mary Back
Kathy Rhoades on fri 28 oct 05
Hi Mary,
Here is my recipe for Randy's Red:
Chemical Base Formula 5,000g 10,000g
Kona F-4 20%.........................1,000.............2,000
Gerstley Borate 31%........................1,550.............3,100
Edgar Plastic Kaolin 5%...........................250................500
Talc 14%..........................700..............1,400
Silica(flint) 30%........................1,500...............3,000
add:
Red Iron Oxide 15%..........................750...............1,500
Hope this helps.
Kathy Rhoades
Mary Back wrote:
I have been making pottery for many years but never mixed my own glazes. I
just attended Clay Connections at Front Royal and a potter demonstrated
some wonderful pieces glazed with Randy's Red Glaze. I found the formula
on the internet but can not determine all the components and would like
some help so that I can buy the material and mix the glaze successfully.
Unity Formula for Randy's Red:
0.046 K20 0.189 Al2O3 2.886 SiO2
0.135 Na2O 0.376 B2O3 0.001 TiO2
0.404 CaO 0.004 Fe2O3
0.416 MgO 0.000 P2O5
15.3:1 Si:Al Ratio
The first column has a bracket pointing to the middle column and the last
column on the right has a bracket pointing to the middle.
I know that
K2O is Potassuim Oxide
Na2O is Borax
CaO is Calcium Oxide
MgO is Magnesium Oxide
Al2O3 is Boric Oxide
B2O3 is Boric Oxide
Fe2O3 is Iron Oxide
P2O5 ??????? can't find
SiO2 is Silica, Flint, Quartz
TiO2 is Titanium Oxide
I guess that the numbers means percentage? or grams?
And I read that Al2O3 and SiO2 is clay? then do I need Silica?
Lots of questions but it is important to me to find out how to buy and mix
this glaze. It is beautiful!!!!! Mary Back
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Paul Lewing on fri 28 oct 05
on 10/28/05 12:15 PM, Mary Back at maryback@MSN.COM wrote:
Ah, Mary, where to begin? First of all, what you have here is a unity
formula, not a recipe. It's an analysis of a molecule of fired Randy's Red.
What you need is a recipe that lists the raw ingredients. Look in the
archives. There's been extensive discussion about this glaze. You're not
the first to be intrigued by it. Keep in mind that this glaze is very
tricky, and that application, atmosphere, and firing cycles make huge
differences in the fired result.
But let me also comment on the rest of your post.
> Unity Formula for Randy's Red:
>
> 0.046 K20 0.189 Al2O3 2.886 SiO2
> 0.135 Na2O 0.376 B2O3 0.001 TiO2
> 0.404 CaO 0.004 Fe2O3
> 0.416 MgO 0.000 P2O5
>
> 15.3:1 Si:Al Ratio
>
> The first column has a bracket pointing to the middle column and the last
> column on the right has a bracket pointing to the middle.
I have no idea what is meant by these brackets. Maybe someone else can
comment.
>
> I know that
> K2O is Potassuim Oxide
> Na2O is Borax No, this is sodium oxide.
> CaO is Calcium Oxide
> MgO is Magnesium Oxide
> Al2O3 is Boric Oxide No, this is aluminum oxide, or alumina.
> B2O3 is Boric Oxide
> Fe2O3 is Iron Oxide
> P2O5 ??????? can't find This is phosphoric oxide.
> SiO2 is Silica, Flint, Quartz
> TiO2 is Titanium Oxide
>
> I guess that the numbers means percentage? or grams?
This is the Seger Formula method of analyzing glazes. It's called a unity
formula, or flux unity, because the fluxes (the elements in the first
column) add up to 1. Beyond that, there's a whole system, which I suggest
you read up on in any number of good textbooks.
Paul Lewing, Seattle
Kathy Rhoades on fri 28 oct 05
Hi again Mary,
I checked my message to you and on my computer it doesn't show up the way I typed it. The percents all go under the base, the first set of numbers goes under the 5000g, and the last under the 10,000g. Now....I hope this helps!
Kathy Rhoades
Mary Back wrote:
I have been making pottery for many years but never mixed my own glazes. I
just attended Clay Connections at Front Royal and a potter demonstrated
some wonderful pieces glazed with Randy's Red Glaze. I found the formula
on the internet but can not determine all the components and would like
some help so that I can buy the material and mix the glaze successfully.
Unity Formula for Randy's Red:
0.046 K20 0.189 Al2O3 2.886 SiO2
0.135 Na2O 0.376 B2O3 0.001 TiO2
0.404 CaO 0.004 Fe2O3
0.416 MgO 0.000 P2O5
15.3:1 Si:Al Ratio
The first column has a bracket pointing to the middle column and the last
column on the right has a bracket pointing to the middle.
I know that
K2O is Potassuim Oxide
Na2O is Borax
CaO is Calcium Oxide
MgO is Magnesium Oxide
Al2O3 is Boric Oxide
B2O3 is Boric Oxide
Fe2O3 is Iron Oxide
P2O5 ??????? can't find
SiO2 is Silica, Flint, Quartz
TiO2 is Titanium Oxide
I guess that the numbers means percentage? or grams?
And I read that Al2O3 and SiO2 is clay? then do I need Silica?
Lots of questions but it is important to me to find out how to buy and mix
this glaze. It is beautiful!!!!! Mary Back
______________________________________________________________________________
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.
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Joe and Lisa Troncale on fri 28 oct 05
Mary,
That just gives you the percentages by weight. This is not the recipe, which
I am sure is available somewhere.
Joe
----- Original Message -----
From: "Mary Back"
To:
Sent: Friday, October 28, 2005 3:15 PM
Subject: Randy's Red Glaze
>I have been making pottery for many years but never mixed my own glazes. I
> just attended Clay Connections at Front Royal and a potter demonstrated
> some wonderful pieces glazed with Randy's Red Glaze. I found the formula
> on the internet but can not determine all the components and would like
> some help so that I can buy the material and mix the glaze successfully.
>
> Unity Formula for Randy's Red:
>
> 0.046 K20 0.189 Al2O3 2.886 SiO2
> 0.135 Na2O 0.376 B2O3 0.001 TiO2
> 0.404 CaO 0.004 Fe2O3
> 0.416 MgO 0.000 P2O5
>
> 15.3:1 Si:Al Ratio
>
> The first column has a bracket pointing to the middle column and the last
> column on the right has a bracket pointing to the middle.
>
> I know that
> K2O is Potassuim Oxide
> Na2O is Borax
> CaO is Calcium Oxide
> MgO is Magnesium Oxide
> Al2O3 is Boric Oxide
> B2O3 is Boric Oxide
> Fe2O3 is Iron Oxide
> P2O5 ??????? can't find
> SiO2 is Silica, Flint, Quartz
> TiO2 is Titanium Oxide
>
> I guess that the numbers means percentage? or grams?
> And I read that Al2O3 and SiO2 is clay? then do I need Silica?
> Lots of questions but it is important to me to find out how to buy and mix
> this glaze. It is beautiful!!!!! Mary Back
>
> ______________________________________________________________________________
> 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.
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.362 / Virus Database: 267.12.5/150 - Release Date: 10/27/2005
>
>
Steve Slatin on fri 28 oct 05
Mary --
What you have done is found a 'unity formula' for a
named glaze. The unity formula is not a recipe for
MIXING the glaze, it is a formula for EVALUATING the
glaze.
The unity formula takes all of the elements generally
identified as 'melters' adds the concentrations of
ions of each element together and takes the total as
one (that is, the number one). Concentrations of
glass formers, stiffeners and colorants are then
evaluated as relative concentrations of ions (relative
to the artificial one-ness of the melters). It is an
interesting way to think of a glaze, and some people
swear by it as a learning tool, but it by no means
helps you to mix a glaze up.
I have seen many, many different recipes for mixing up
"Randy's Red" and if the real Randy is offended by
this, I apologize, but many seem to circulate around
the following for the cone 6 formulations, which is
from the DigitalFire site --
50% Gerstley Borate or acceptible substitute for same
30% Silica, Quartz, or Flint
20% Kaolin, EPK or equivalent
----------
100% <-- most glazes are stated to add up to 100%
not including suspenders, emulsifiers, or
colorants, this is also the end of the part
of the recipe sometimes referred to as
'above the line'
15% Red Iron Oxide (some recipes call for Spanish red,
others do not.
2% Bentonite if you will dip or pour, use CMC if you
will brush your glaze
This recipe gives a Silica to Alumina ratio of about 9
(not including the bentonite). People who experiment
regularly with Randy's Red say that it's not reliably
a red color at these ratios, and is most likely to
give a real red if the Si/Al ratio is 18 to one. Of
course, the higher that ratio gets, the more likely
the glaze will run right off the pot, leading to an
excessive use of strong langugage, chisels, etc.
An extreme-but-not-too-extreme version of the mix, the
source of which is not in my notes (and my apologies
to whoever did the work for not naming you) is
Kona (F-4) Feldspar -- 20%
Gerstley Borate -- 31%
EPK -- 5%
Talc -- 14%
Silica -- 30%
-------------------------
100%
Iron Oxide 15%
Bentonite 2%
This gets you to a 15 to 1 silica/alumina ratio, close
to the number recommended by the REP*, but which might
not ruin all of your shelves -- at least not if
applied thin on the lower part of the pot.
I have no notes on where I got this iteration of
Randy's Red; based on what I've read about Red, it's
more likely to work, but I've not ever used it myself.
This recipe, relative to the unity formula you have
'flips' the potassium/sodium concentrations, but I've
never myself seen that to make much of a difference,
is very close on calcium and magnesium, so that the
total of melters is quite similar -- then the boron is
only slightly higher, the alumina is slightly higher
but so is the silica ... so the ratio remains similar
...
In any event, if you contact the place or the potter
that showed the glaze, perhaps they'll give you a
hint/push in the right direction. After that, the
only thing for you is to test (carefully with those
potentially runny glazes) over and over until you find
something that works reliably for you.
Best wishes, and if you have something work well,
please share your success.
-- Steve Slatin
* runny extremist party
--- Mary Back wrote:
> I have been making pottery for many years but never
> mixed my own glazes. I
> just attended Clay Connections at Front Royal and a
> potter demonstrated
> some wonderful pieces glazed with Randy's Red Glaze.
> I found the formula
> on the internet but can not determine all the
> components and would like
> some help so that I can buy the material and mix the
> glaze successfully.
>
> Unity Formula for Randy's Red:
>
> 0.046 K20 0.189 Al2O3 2.886 SiO2
> 0.135 Na2O 0.376 B2O3 0.001 TiO2
> 0.404 CaO 0.004 Fe2O3
> 0.416 MgO 0.000 P2O5
>
> 15.3:1 Si:Al Ratio
>
> The first column has a bracket pointing to the
> middle column and the last
> column on the right has a bracket pointing to the
> middle.
>
> I know that
> K2O is Potassuim Oxide
> Na2O is Borax
> CaO is Calcium Oxide
> MgO is Magnesium Oxide
> Al2O3 is Boric Oxide
> B2O3 is Boric Oxide
> Fe2O3 is Iron Oxide
> P2O5 ??????? can't find
> SiO2 is Silica, Flint, Quartz
> TiO2 is Titanium Oxide
>
Steve Slatin --
Drove downtown in the rain
9:30 on a Tuesday night
Just to check out the
Late night record shop
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