Eric Hansen on mon 7 jun 10
DRB: I like the phrase "well known to industry" - that doesn't mean its wel=
l
known generally speaking. It is however a perfect example of the
paleo/historical development of "bristol" glazes - in the Ohio Valley heavy
ceramics environment; e.g. (see Parmelee) it is the basic potassium/calcium
glaze with zinc taking the place of part of the calcium. Cardew sticks to
his guns pretty much in that he uses the Unity AS the recipe, and for his
purposes, establishing potteries in far-away regions, where even
substitutions for materials becomes difficult, I can see why. Times have
changed in the industry and now half a dozen fluxes might be used in place
of these two. For sure barium would be in there. Your elegant design
solution has that aesthetic downside; In his book John Britt suggests rutil=
e
or titanium to get more of a "pottery" look. Still I'm wondering what a
healthy % of barium would do? Myself i just leave the RO in the RO column,
etc. because how a glaze performs can't be easily predicted from Unity
alone. Things like iron, boron, and mesh sizes of stuff that never melts
makes that kind of approach nearly impossible. But that is just me.
h a n s e n
On Mon, Jun 7, 2010 at 5:03 PM, douglas fur <23drb50@gmail.com> wrote:
> This is a formula from Cardew P.P. pg 137 for a mid range glaze using zin=
c-
> 0.4 K/Na .6 Al2O3 3.55 SiO2
> 0.3 CaO
> 0.3 ZnO
>
> I've been running tests with zinc zirconium silicate which has the double
> benefit of adding an opacifier and eliminating the granular bits in zinc
> oxide which can survive firing as white zits in the glaze. Its down-side =
is
> it can make a glaze that looks like cream cheese wrapped in saran wrap
> rather than the melted stone look of a good stoneware glaze.)
> It ALSO raises the nice theoretical question- do you count ZrO2 as part o=
f
> the RO2 and therefore reduce the SiO2 or ignore it and only use SiO2 to
> satisfy the RO2?
> DRB
> Seola Creek
>
douglas fur on mon 7 jun 10
This is a formula from Cardew P.P. pg 137 for a mid range glaze using zinc-
0.4 K/Na .6 Al2O3 3.55 SiO2
0.3 CaO
0.3 ZnO
I've been running tests with zinc zirconium silicate which has the double
benefit of adding an opacifier and eliminating the granular bits in zinc
oxide which can survive firing as white zits in the glaze. Its down-side is
it can make a glaze that looks like cream cheese wrapped in saran wrap
rather than the melted stone look of a good stoneware glaze.)
It ALSO raises the nice theoretical question- do you count ZrO2 as part of
the RO2 and therefore reduce the SiO2 or ignore it and only use SiO2 to
satisfy the RO2?
DRB
Seola Creek
Eric Hansen on tue 8 jun 10
I need to go back to school on the math, I think I will take my Charles
McKee with me to work tonite.
I'm changing my objectives in clay currently. I have been making teabowls;
which I recommend as a great exercise in the learning curve, they are like
test tiles actually. But I've noticed some bowls get used a lot more than
others. I'm appreciating the ones that get used more. Now my shelves need
more dishes. I like what the Louisville potters have done too: Byron Temple
and also Fong Choo.
h a n s e n
On Tue, Jun 8, 2010 at 7:51 PM, Eric Hansen
wrote:
> *Douglas: That is interesting. Here are numbers for Red Horse and Red Art=
,
> I wanted to compare Lizella too , but it isn't immediately available. Did
> you single fire with this glaze then? *
>
> *h a n s e n*
>
> *
> *
>
> *Red Horse Clay*
>
> *
> *
>
> *Percentage Analysis*
>
> **
>
> * 67.59 % SiO*2* *
>
> * 22.03 % Al*2*O*3
>
> * 1.20 % K*2*O *
>
> * 0.30 % Na*2*O *
>
> * 0.62 % MgO *
>
> * 0.45 % CaO *
>
> * 6.62 % Fe*2*O*3
>
> * 1.18 % L.O.I.*
>
> *______________*
>
> *99.99 % TOTAL*
>
> *
> *
>
> *
> *
>
> *
> *
>
> *Red Art Clay*
>
> *
> *
>
> **
> *
>
> Percentage Analysis
>
>
> 64.28 % SiO2
>
> 16.41 % Al2O3
>
> 4.07 % K2O
>
> 0.40 % Na2O
>
> 1.55 % MgO
>
> 0.23 % CaO
>
> 0.17 % P2O5
>
> 7.04 % Fe2O3
>
> 1.06 % TiO2
>
> 4.78 % L.O.I.
>
> ______________
>
> 99.99 % TOTAL
> *
>
>
> On Tue, Jun 8, 2010 at 5:43 PM, Eric Hansen m
> > wrote:
>
>> I've read the Leach, Cardew, and Parmelee, but not the Bourry. That soun=
ds
>> intriguing -
>> h a n s e n
>>
>> On Tue, Jun 8, 2010 at 2:07 PM, douglas fur <23drb50@gmail.com> wrote:
>>
>>>
>>>
>>> Eric Hansen
>>> I appreciate the phrase "well known to industry". As you point out its
>>> more historic than contemporary but then a lot of the technology we use=
is
>>> anachronistic which is why sources like Leach, Bourry and Parmalee are =
still
>>> useful.
>>>
>>> The universality of the Seger formula works for doing substitutions whe=
n
>>> your materials are apples and oranges to each other or odd-ball. I got=
a
>>> good iron red using Parmalee's formula form Cardew and by calculating a
>>> unity formula for Red Horse based on an ultimate analysis in %. Some
>>> Custer, some Red Horse, plus a pinch of cryolite to satisfy the R2O and=
I
>>> got a glaze on the first try. As you say, its not a sure thing- in my =
last
>>> series I got two melts out of 8 trials.
>>>
>>> DRB
>>> Seola Creek
>>>
>>>
>>>
>>
>
douglas fur on tue 8 jun 10
Eric Hansen
I appreciate the phrase "well known to industry". As you point out its more
historic than contemporary but then a lot of the technology we use is
anachronistic which is why sources like Leach, Bourry and Parmalee are stil=
l
useful.
The universality of the Seger formula works for doing substitutions when
your materials are apples and oranges to each other or odd-ball. I got a
good iron red using Parmalee's formula form Cardew and by calculating a
unity formula for Red Horse based on an ultimate analysis in %. Some
Custer, some Red Horse, plus a pinch of cryolite to satisfy the R2O and I
got a glaze on the first try. As you say, its not a sure thing- in my last
series I got two melts out of 8 trials.
DRB
Seola Creek
Eric Hansen on tue 8 jun 10
I've read the Leach, Cardew, and Parmelee, but not the Bourry. That sounds
intriguing -
h a n s e n
On Tue, Jun 8, 2010 at 2:07 PM, douglas fur <23drb50@gmail.com> wrote:
>
>
> Eric Hansen
> I appreciate the phrase "well known to industry". As you point out its mo=
re
> historic than contemporary but then a lot of the technology we use is
> anachronistic which is why sources like Leach, Bourry and Parmalee are st=
ill
> useful.
>
> The universality of the Seger formula works for doing substitutions when
> your materials are apples and oranges to each other or odd-ball. I got a
> good iron red using Parmalee's formula form Cardew and by calculating a
> unity formula for Red Horse based on an ultimate analysis in %. Some
> Custer, some Red Horse, plus a pinch of cryolite to satisfy the R2O and I
> got a glaze on the first try. As you say, its not a sure thing- in my la=
st
> series I got two melts out of 8 trials.
>
> DRB
> Seola Creek
>
>
>
ivor and olive lewis on wed 9 jun 10
Dear Eric Hansen,
You may wish to consider adding the following title to your reading list.
Felix and Sonya Singer, "Industrial Ceramics" (sorry, do not have the ISBN
code) My recollection is that there is a chapter on developing Bristol
Glazes.
As an aside, I did some tests with Barium Carbonate some years ago. Contrar=
y
to what I had read about higher proportions giving opaque glazes, I achieve=
d
transparent examples with well over twenty percent Barium Carbonate.
Regards.
Ivor Lewis,
REDHILL,
South Australia
douglas fur on fri 11 jun 10
Ivor
Sorry for all the white space... I googled your title and found it on
amazon. Yow$$$ must be a good book.
DRB
Seola Creek
Industrial Ceramics [Import] [Hardcover]Felix & Sonja S. Singer
Singer=3Drelevancerank&search-alias=3Dbooks&field-author=3DFelix%20%26%20Sonja%20=
S.%20Singer%20Singer>(Author),
Illustrated&sort=3Drelevancerank&search-alias=3Dbooks&field-author=3DIllustrated>(Illu=
strator)
** ** **
*1 used*d?ie=3DUTF8&condition=3Dused>
from $955.32
mazon Price New from Used from Expand
#>
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#>
Hardcoverref=3Dtmm_hrd_title_0/181-2075743-3667761>
popover_img/181-2075743-3667761>
Hardcoverref=3Dtmm_hrd_title_popover_0/181-2075743-3667761>
*Available from **these
sellers*_olp/181-2075743-3667761?ie=3DUTF8&condition=3Dall>
*.*
Publisher: Springer
Published: June 1, 1963
-- -- $627.30_hrd_used_olp_0/181-2075743-3667761?ie=3DUTF8&condition=3Dused>
Hardcover,
Import, 1963
/ref=3Doe_popover_img/181-2075743-3667761>
Hardcover, Importger/dp/B0000EG0C6/ref=3Dtmm_hrd_title_popover_sr/181-2075743-3667761>
*Available from **these
sellers*_olp/181-2075743-3667761?ie=3DUTF8&condition=3Dall>
*.*
Publisher: Chemical Publishing Co.
Published: 1963
-- -- $955.32_hrd_used_olp_sr/181-2075743-3667761?ie=3DUTF8&condition=3Dused>
*See # more hardcoversa-Singer/dp/B0000EG0C6#>
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