David Hendley on thu 26 aug 10
----- Original Message -----
> would you please lead us to, or give us a basic recipe
> for cone 10 cones.
> and, some basic inform on making them.
> molds, drying.
> or, tell us where to look.
> thanks.
> mel
> from: minnetonka, mn
Mel,
Reading "The Potter's Alternative" by Harry Davis got me
interested in making my own cones. Like Cardew's
"Pioneer Pottery", this book was written for potters wanting
to set up shop in undeveloped areas with no ceramic
suppliers. Believe me, making cones is actually one of the
simplest tasks detailed in the book, compared to mining
clay, building rock crushers, and building kilns with no
store-bought materials.
If you've ever wondered why cone 10 is called "cone 10",
it is because the unity molecular formula for cone 10, as
developed by Hermann Seger, is
.7 potash
.3 calcium
1 alumina
10 silica
Cone 6 is:
.7 potash
.3 calcium
.6 alumina
6 silica
get it?
Seger started at cone 6 and went higher, so this relationship
holds for any cone from 6 upwards.
Others, later, developed formulae for lower temperatures,
mostly by adding iron to the mix.
Later still, the even lower-bending "0" cone formulae were
developed.
So, it is a matter of using glaze calculation to develop a
recipe from a formula, just as is done for a glaze - Simple
with a glaze calculation program. The only important point
to keep in mind is to try to incorporate some plastic clay
materials in the recipe, to hold everything together.
In "The Potter's Alternative", Davis suggests making cone
molds out of sheet metal, complete with measurements and
drawings. Instead, I decided to make a plaster cone mold.
I made a "gang mold" of 6 or 7 cones by using commercial
cones to shape the plaster. I bisque-fired and mold-soaped
the cones, so they wouldn't disintegrate from the water in the
plaster, and could later be used as cones.
In use, I mix up a 200 gram batch of the cone recipe, same
as a glaze, then dry it to plastic consistency and put it in
the mold. I over-fill the cavities then cut them off level
with a 6" drywall blade. The cones are ready to remove
from the mold in a few minutes. I use a needle tool to
pierce the cone near its base, to easily remove from the
mold using the needle. 200 grams makes about 50 cones!
They are very fragile. I bisque fire the hotter cones for
durability (I also bisque fire commercial cones in their
cone packs).
In practice, through test firings, my cones end up being a
little "off" from the theoretical formulae. My cone 10 is:
Custer feldspar 17
whiting 7
OM#4 ball clay 37
silica 31
My "cone 9" ended up bending before a commercial
cone 9. I found this useful and just left it as is, and call it
"cone 8 1/2":
Custer feldspar 22.5
whiting 9
OM#4 ball clay 29
silica 39.5
As Davis says, "Some means of measuring the temperature
of kilns is essential, but it is more important to be able to
repeat a given temperature than to know exactly what
degree has been reached."
I also developed a cone 06. I based it on Redart clay,
reasoning that commercial cones in this range are red:
Redart clay 48.5
Custer feldspar 9
Gerstley borate 28
whiting 10.5
Of course, testing is essential for developing cone recipes.
I found that the physical size of the cone is critical. The
molds must be completely and evenly filled or the resulting
cones will exhibit slight variations.
Read "The Potter's Alternative" and "Pioneer Pottery"
if you want to know more. Making cones is an excellent
experience for learning about ceramic materials and, since
they are kind of halfway between the two, understanding
glazes and claybodies.
Good luck, Mel, at your End of the Summer Sale this
weekend. It is still way to hot in Texas to be thinking
about such things.
David Hendley
david@farmpots.com
http://www.farmpots.com
http://www.thewahooligans.com
Nancy Spinella on fri 27 aug 10
How serendipitous! I was just wondering the other day why the cone chart
was the way it was, and why there are "0" cones rather than just starting
out at a lower number to begin with. Thanks so much for saving me the
research!! :)
--Nancy
On Fri, Aug 27, 2010 at 12:04 AM, David Hendley wrote:
>
> If you've ever wondered why cone 10 is called "cone 10",
> it is because the unity molecular formula for cone 10, as
> developed by Hermann Seger, is
> .7 potash
> .3 calcium
> 1 alumina
> 10 silica
>
> Cone 6 is:
> .7 potash
> .3 calcium
> .6 alumina
> 6 silica
>
> get it?
www.twitter.com/nanspins
www.wix.com/nanspin/pottery
Neon-Cat on fri 27 aug 10
Thanks David, for posting about cone-making!
A "Sizes" site, Robert? What are you guys measuring tonight?
Edouard's info is first rate, as usual. It's in line with charts from
a number of ceramic books, Susan and Jan Peterson's "The Craft and Art
of Clay" included. Those gals are usually long and strong on correct
info, too.
Drink one for me:>)
Cheers,
your loving list cat
Robert Harris on fri 27 aug 10
Just a quick note of caution.
Seger Cone 10 is NOT the same as Orton Cone 10.
Orton Cone 10 is very approximately Seger Cone 8. This is why Bernard
Leach refers in his books to his glazes as cone 8 glazes, whereas we
would calculate them as orton cone 10 glazes. This confused me for a
long time until I realised that BL used Seger cones.
On Fri, Aug 27, 2010 at 7:53 AM, Nancy Spinella wrote:
> How serendipitous! =3DA0I was just wondering the other day why the cone c=
ha=3D
rt
> was the way it was, and why there are "0" cones rather than just starting
> out at a lower number to begin with. =3DA0Thanks so much for saving me th=
e
> research!! :)
>
> --Nancy
>
> On Fri, Aug 27, 2010 at 12:04 AM, David Hendley wrot=
=3D
e:
>
>>
>> If you've ever wondered why cone 10 is called "cone 10",
>> it is because the unity molecular formula for cone 10, as
>> developed by Hermann Seger, is
>> .7 potash
>> .3 calcium
>> 1 alumina
>> 10 silica
>>
>> Cone 6 is:
>> .7 potash
>> .3 calcium
>> .6 alumina
>> 6 silica
>>
>> get it?
>
>
>
> www.twitter.com/nanspins
> www.wix.com/nanspin/pottery
>
--=3D20
----------------------------------------------------------
douglas fur on fri 27 aug 10
Mel-sensei
Can you help us with why Orton cones and the "seger" cones have different
firing points?
I'd like to see if anyone's curiosity has driven them to get some seger
cones and fired them side by side.
DRB
Seola Creek
Robert Harris on fri 27 aug 10
Oddly, the Seger cone table I found
http://www.sizes.com/units/seger_cones.htm
is VERY different than Edouard's.
(and more in line with my previous post).
R
On Fri, Aug 27, 2010 at 6:11 PM, Edouard Bastarache wr=
ote:
> Orton Cones :
> http://smart2000.pagesperso-orange.fr/cones%20Orton.htm
>
> Seger Cones :
> http://smart2000.pagesperso-orange.fr/cones%20de%20seger.htm
>
> Gis,
>
> Edouard Bastarache
> Spertesperantisto
>
> Sorel-Tracy
> Quebec
>
> http://www.flickr.com/photos/30058682@N00/
> http://edouardbastarache.blogspot.com/
> http://blogsalbertbastarache.blogspot.com/
> http://cerampeintures.blogspot.com/
> http://www.facebook.com/edouard.bastarache
>
>
>
> ----- Original Message ----- From: "Robert Harris" OM>
> To:
> Sent: Friday, August 27, 2010 3:54 PM
> Subject: Re: Cones - roll your own
>
>
> Just a quick note of caution.
>
> Seger Cone 10 is NOT the same as Orton Cone 10.
>
> Orton Cone 10 is very approximately Seger Cone 8. This is why Bernard
> Leach refers in his books to his glazes as cone 8 glazes, whereas we
> would calculate them as orton cone 10 glazes. This confused me for a
> long time until I realised that BL used Seger cones.
>
> On Fri, Aug 27, 2010 at 7:53 AM, Nancy Spinella wrot=
e:
>>
>> How serendipitous! I was just wondering the other day why the cone chart
>> was the way it was, and why there are "0" cones rather than just startin=
g
>> out at a lower number to begin with. Thanks so much for saving me the
>> research!! :)
>>
>> --Nancy
>>
>> On Fri, Aug 27, 2010 at 12:04 AM, David Hendley
>> wrote:
>>
>>>
>>> If you've ever wondered why cone 10 is called "cone 10",
>>> it is because the unity molecular formula for cone 10, as
>>> developed by Hermann Seger, is
>>> .7 potash
>>> .3 calcium
>>> 1 alumina
>>> 10 silica
>>>
>>> Cone 6 is:
>>> .7 potash
>>> .3 calcium
>>> .6 alumina
>>> 6 silica
>>>
>>> get it?
>>
>>
>>
>> www.twitter.com/nanspins
>> www.wix.com/nanspin/pottery
>>
>
>
>
> --
> ----------------------------------------------------------
>
>
--
----------------------------------------------------------
Edouard Bastarache on fri 27 aug 10
Orton Cones :
http://smart2000.pagesperso-orange.fr/cones%20Orton.htm
Seger Cones :
http://smart2000.pagesperso-orange.fr/cones%20de%20seger.htm
Gis,
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://www.flickr.com/photos/30058682@N00/
http://edouardbastarache.blogspot.com/
http://blogsalbertbastarache.blogspot.com/
http://cerampeintures.blogspot.com/
http://www.facebook.com/edouard.bastarache
----- Original Message -----
From: "Robert Harris"
To:
Sent: Friday, August 27, 2010 3:54 PM
Subject: Re: Cones - roll your own
Just a quick note of caution.
Seger Cone 10 is NOT the same as Orton Cone 10.
Orton Cone 10 is very approximately Seger Cone 8. This is why Bernard
Leach refers in his books to his glazes as cone 8 glazes, whereas we
would calculate them as orton cone 10 glazes. This confused me for a
long time until I realised that BL used Seger cones.
On Fri, Aug 27, 2010 at 7:53 AM, Nancy Spinella wrote:
> How serendipitous! I was just wondering the other day why the cone chart
> was the way it was, and why there are "0" cones rather than just starting
> out at a lower number to begin with. Thanks so much for saving me the
> research!! :)
>
> --Nancy
>
> On Fri, Aug 27, 2010 at 12:04 AM, David Hendley
> wrote:
>
>>
>> If you've ever wondered why cone 10 is called "cone 10",
>> it is because the unity molecular formula for cone 10, as
>> developed by Hermann Seger, is
>> .7 potash
>> .3 calcium
>> 1 alumina
>> 10 silica
>>
>> Cone 6 is:
>> .7 potash
>> .3 calcium
>> .6 alumina
>> 6 silica
>>
>> get it?
>
>
>
> www.twitter.com/nanspins
> www.wix.com/nanspin/pottery
>
--
----------------------------------------------------------
Randall Moody on sat 28 aug 10
I don't really get why you would take the time and effort to develop and
make your own cones. It is a bit like re-inventing the wheel.
--
Randall in Atlanta
http://wrandallmoody.com/home.html
John Britt on sat 28 aug 10
My understanding from reading David Green's great book is that the reaso=
=3D
n
cone numbering is weird is that Seger developed cone 4 first, then went u=
=3D
p.
( it is a 1/10 ratio of moles of alumina to silica...so 0.5 moles of
alumina to 5 moles of silica is cone 5, and 0.6/6 is cone 6, 0.7/7 is con=
=3D
e
7, 0.8/8 is cone 8.)
Then he and others developed the lower cones 3, 2, 1 so when they came to=
=3D
zero they were stuck and had to add the "0" . So you get 01, 02,03, etc.=3D=
20=3D
So cones are numbered like BC/ AD. Reverse then forward.
www.johnbrittpottery.com
Edouard Bastarache on sat 28 aug 10
Neon,
the charts I sent are published on Denis Caraty's site
(aka Smart.Conseil) who is the R&D technologist
at the Gien Factory in France :
http://www.gien.com/jp/decouvrir/default.htm
He uses Seger's every day.
Gis,
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://www.flickr.com/photos/30058682@N00/
http://edouardbastarache.blogspot.com/
http://blogsalbertbastarache.blogspot.com/
http://cerampeintures.blogspot.com/
http://www.facebook.com/edouard.bastarache
----- Original Message -----
From: "Neon-Cat"
To:
Sent: Saturday, August 28, 2010 12:17 AM
Subject: Re: Cones - roll your own
> Thanks David, for posting about cone-making!
>
> A "Sizes" site, Robert? What are you guys measuring tonight?
> Edouard's info is first rate, as usual. It's in line with charts from
> a number of ceramic books, Susan and Jan Peterson's "The Craft and Art
> of Clay" included. Those gals are usually long and strong on correct
> info, too.
>
> Drink one for me:>)
>
> Cheers,
> your loving list cat
>
ivor and olive lewis on sat 28 aug 10
Dear David Hendley,
I have just checked the values you give for the Unity Molecular Composition
for the Seger Pyrometric Cones
I believe your have interchanged the values for Potassium Oxide and Calcium
Oxide.
See DeBoos, Harrison and Smith, "Handbook for Australian Potters", Appendix
3, "Composition of Seger Cones for various temperatures." p298. ISBN
0-454-00448-6
Regards,
Ivor Lewis,
REDHILL,
South Australia
Joseph Herbert on sat 28 aug 10
The Lange's Handbook of Chemistry for 1946 lists chemical compositions for
most of the pyrometric cones. Indeed, the relationship David points out is
evident. A similar relationship between cone numbers and composition is no=
t
easy to find elsewhere. However, one of the things I find most interesting
is the lack of any pattern of increasing cone number and temperature
difference between cones. You can understand that lack in the range David
talks about, since the criteria for the cone number is the composition. Fo=
r
example, the differences in temperature between cone numbers from cone 4 to
cone 12 ranges between 18 degrees f and 49 degrees f. Specifically, the
jumps (starting at c 3 - c 4) are: 47, 32, 47, 29, 18, 23, 49, 38, and 23.
I am not sure any of this means anything, as has been said, consistency is
the real goal.
I would point out that the later cone series, the "0" series, might be
expected to be more "rational" in the variation of temperature increase
between cone numbers, but is not. Some vary by over 80 degrees while other=
s
less than 20 degrees. Perhaps some of the cones were compounded to fill
specific industrial needs. In any event, trying to accurately predict an
amount of temperature increase over a span of cone numbers without referrin=
g
to a chart is impossible, or would require an inordinately large number of
thumbs to structure rules around.
Just an observation.
Joe
Joseph Herbert
Training Developer
Lee Love on sun 29 aug 10
On Fri, Aug 27, 2010 at 2:54 PM, Robert Harris wr=
=3D
ote:
> Just a quick note of caution.
>
> Seger Cone 10 is NOT the same as Orton Cone 10.
>
> Orton Cone 10 is very approximately Seger Cone 8. This is why Bernard
> Leach refers in his books to his glazes as cone 8 glazes, whereas we
> would calculate them as orton cone 10 glazes. This confused me for a
> long time until I realised that BL used Seger cones.
Actually, while the cones are slightly different, Hamada and Leach
actually fired at lower temp. (8 Seger does not equal Orton 10.)
Take a look at Edouard's charts below. Seger cost a lot more in
Japan. So I imported Ortons.
seger orton
8 2282 =3DB0 F 2257
9 2336 =3DB0 F 2300
10 2372 =3DB0 F 2345
11 2408 =3DB0 F 2361
=3D09
--
=3DA0Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/
=3D93Experience without theory is blind, but theory without experience is
mere intellectual play.=3D94 --Immanuel Kant
douglas fur on sun 29 aug 10
Edouard Bastarache :
> As you say "the charts I sent are published on Denis Caraty's site
> (aka Smart.Conseil) who is the R&D technologist at the Gien Factory in
> France :
> http://www.gien.com/jp/decouvrir/default.htm"
others have pointed out sources that differ.
What I would like to find out is how cones have come to differ when they
started out with the same theoretical basis.
I think the fact that leach's ^8 clear doesn't melt at ^ 10 for many is due
to differing materials eg "podemore's water ground flint" vis american 325
mesh silica.
Be that as it may, If the stoneware of leach/hamada is fired at a lower
point say ^8/9 orton it would have a different character than stoneware
fired at ^9/10. I think we americans tend to have a "more is better fire
'em flat" attitude and have drifted to higher temperatures which in itself
is not wrong, but if we're to talk about "stoneware" we have to be clear
about how we define the term.
DRB
Seola Creek
David Woof on sun 29 aug 10
Randall=3D2C
from what dark dank orifice did you call forth your question? If you have=
=3D
to ask=3D3B I'm certain that you are pre-convinced not to do it anyway=3D2=
C an=3D
d motivated at best by idle curiosity so it would be wasted precious effort=
=3D
to tell you. ( what?... you want to debate this too?) =3D20
I offer instead a real life tale that reflects on the discussion threads yo=
=3D
u guys have stomped to death and still have not reached a workable definiti=
=3D
on=3D2C consensus=3D2C or conclusion...... It's obvious=3D2C with some few =
rich a=3D
nd provoking exceptions=3D2C that the majority don't want anything out of t=
he=3D
se exchanges but to be heard. So please take it to your "thanks for shari=
=3D
ng" meetings or therapist's couch.
=3D20
Ages ago at a commune I was living at=3D2C we overheard Terrance spend the =
we=3D
e hours quite poetically and emphatically telling Rosie (hi Rosie=3D2C it w=
as=3D
real) how good it was going to be.....but....never.....ever.....ad nauseum=
=3D
never....!!!=3D20
Now I was a young man becoming versed in the "slow hands" delights of savor=
=3D
ing fine conversation=3D2C fine women=3D2C fine wine=3D2C and tasty food=3D=
3B but t=3D
here is a time to get to the point sailor! and Terry had gone way past! =3D=
20
So as dawn was ruffling the feathers of the first waking birds=3D2C being t=
he=3D
gentleman that I am=3D2C I knocked politely and suggested that perhaps Ros=
ie=3D
was hungry and would like to accompany me somewhere quiet to have an early=
=3D
breakfast.
=3D20
David Woof.....Clarkdale=3D2C Arizona......forking thru turds for truffles =
th=3D
is fine Clayart Sunday morning. Keep the good stuff coming and don't debat=
=3D
e words with the semantically challenged or stupid !!!! =3D20
Some folks have no respect for the authority of Webster. But without an au=
=3D
thority all rally to as a starting point=3D2C there can be no meaningful di=
sc=3D
ussion. "Replace guns with dictionaries." Anu Garg
_______________________________________________________________________
6a. Re: Cones - roll your own
Posted by: "Randall Moody" randall.moody@GMAIL.COM=3D20
Date: Sat Aug 28=3D2C 2010 11:48 am ((PDT))
I don't really get why you would take the time and effort to develop and
make your own cones. It is a bit like re-inventing the wheel.
Randall in Atlanta
http://wrandallmoody.com/home.html
=3D20
=3D20
=3D
Eric Hansen on mon 30 aug 10
Orton and Seger cones are made from frits, not raw ingredients,
surely. Otherwise they can't be accurate.
h a n s e n
On Sat, Aug 28, 2010 at 6:57 PM, Edouard Bastarache wr=
ote:
> Neon,
>
> the charts I sent are published on Denis Caraty's site
> (aka Smart.Conseil) who is the R&D technologist
> at the Gien Factory in France :
> http://www.gien.com/jp/decouvrir/default.htm
>
> He uses Seger's every day.
>
> Gis,
>
> Edouard Bastarache
> Spertesperantisto
>
> Sorel-Tracy
> Quebec
>
> http://www.flickr.com/photos/30058682@N00/
> http://edouardbastarache.blogspot.com/
> http://blogsalbertbastarache.blogspot.com/
> http://cerampeintures.blogspot.com/
> http://www.facebook.com/edouard.bastarache
>
>
>
> ----- Original Message -----
> From: "Neon-Cat"
> To:
> Sent: Saturday, August 28, 2010 12:17 AM
> Subject: Re: Cones - roll your own
>
>
>> Thanks David, for posting about cone-making!
>>
>> A "Sizes" site, Robert? What are you guys measuring tonight?
>> Edouard's info is first rate, as usual. It's in line with charts from
>> a number of ceramic books, Susan and Jan Peterson's "The Craft and Art
>> of Clay" included. Those gals are usually long and strong on correct
>> info, too.
>>
>> Drink one for me:>)
>>
>> Cheers,
>> your loving list cat
>>
>
--
Eric Alan Hansen
Stonehouse Studio Pottery
Alexandria, Virginia
americanpotter.blogspot.com
thesuddenschool.blogspot.com
hansencookbook.blogspot.com
"To me, human life in all its forms, individual and aggregate, is a
perpetual wonder: the flora of the earth and sea is full of beauty and
of mystery which seeks science to understand; the fauna of land and
ocean is not less wonderful; the world which holds them both, and the
great universe that folds it in on everyside, are still more
wonderful, complex, and attractive to the contemplating mind." -
Theodore Parker, minister, transcendentalist, abolitionist (1810-1860)
Mike on mon 30 aug 10
Cost more is right, and a bit of an understatement. I checked
yesterday, and the avg. price I found was 2650 yen for a box of 10 seger
cones. That's about $3 per cone at the current exchange rate. Yikes!
Since I use only one cone in my current gas kiln, it's no problem.
However, this fall when the wood kiln is built, I probably won't be able
to get away with just one, or even 10 maybe.... One of the previous
mails asked why anyone would go through the trouble of making their own
cones, and this (cost) is one good reason, though if I fired with Orton
cones I don't think cost would be much of a consideration.
I've noticed that the potters here in my area are somewhat more frugal
with cones than their American counterparts, and I think the reason is
price.
So, switching to Orton may be the just the thing. Or perhaps making
one's own, considering that one little batch yields so many cones. The
satisfaction of having made your own would be considerable too, I think.
Mike
in Taku,
Japan
http://karatsupots.com
http://karatsupots.blogspot.com
Kiln Building Workshop, Oct. 15 - 22
http://karatsupots.com/workshop2010/workshop2010.html
http://karatsupots-workshop.blogspot.com/
> Actually, while the cones are slightly different, Hamada and Leach
> actually fired at lower temp. (8 Seger does not equal Orton 10.)
> Take a look at Edouard's charts below. Seger cost a lot more in
> Japan. So I imported Ortons.
>
> seger orton
>
> 8 2282 =C2=B0 F 2257
> 9 2336 =C2=B0 F 2300
> 10 2372 =C2=B0 F 2345
> 11 2408 =C2=B0 F 2361
>
> --
> Lee, a Mashiko potter in Minneapolis
> http://mingeisota.blogspot.com/
>
> =E2EURoeExperience without theory is blind, but theory without experience=
is
> mere intellectual play.=E2EUR=9D --Immanuel Kant
>
ivor and olive lewis on mon 30 aug 10
Perhaps it is worth remembering that the temperatures assigned to pyrometri=
c
cones, which ever flavour and working temperature you select, is dependent
on being heated at a specific temperature gradient. under standardised
conditions..
The Deformation of a cone is a response to Energy adsorption, that is the
number of Joules in a Time Period and the ability of materials from which
cones are made respond to that energy. This process is driven by temperatur=
e
difference, Heat Energy having the ability to flow from regions of high
temperature the regions of low temperature.
To mature clay and glaze the temperature of the interior kiln environment
must always be higher than the anticipated deformation temperature of the
cone being used.
Regards,.
Ivor Lewis,
REDHILL,
South Australia
Neon-Cat on mon 30 aug 10
Hi Robert,
Seger cones are designed to fuse at specific temperature intervals to
give you a time-temperature ratio. They fold over at a certain
temperature. Several texts I have state that the heat up rate is 150
degrees C per hour (302 F/hr) for a Seger cone. They say that
accelerating the rate will make the cones take longer to double over.
So use an Orton chart that says "when heated at 150 C/hr"
The Orton link Edouard gave you seems to be one for 150 C/hr. Or go to
Orton's site for one. Or I can email you one in a word doc.
Good luck and have fun!
Marian
neoncat
Paul Herman on mon 30 aug 10
Robert,
I also had crazing from Leach's cone 8 glaze (1234), when fired to
Orton cone 10/11, on my clay bodies. I ended up increasing the kaolin
from 10 to 16 and the silica from 30 to 36, if I remember correctly. I
now use it for one of my celadon glazes (with 1% added red iron) in
wood or gas firings. It's very dependable, tough and scratch
resistant, and takes excessive heat well in the wood fire. Firing
lower would not help, IMO.
best wishes,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
On Aug 30, 2010, at 1:32 PM, Robert Harris wrote:
> I wonder how his 4321 glaze looks when fired to Seger 8. Certainly
> when fired to 2305F (at a ramp rate that makes cone 10 bend to 10
> o'clock and the tip of cone 9 touching the shelf) I have real crazing
> problems. Perhaps at a lower temp I wouldn't get crazing?
Lee Love on mon 30 aug 10
On Mon, Aug 30, 2010 at 3:32 PM, Robert Harris wr=
=3D
ote:
> As I recall Leach had very long, wood, then oil, firings (24hrs+?
> heating) so his final temperature might have been less even than
> 1250C. Or potentially we are examining the incorrect Orton table in
> our direct comparisons.
Robert, you are correct Before the climbing kilns, the tube kilns
rarely got over 2000*F Even in the more efficent climbing kilns,
there are spots that don't even get that hot. That is why they had
to fire for days or weeks to do the heat work.
> I wonder how his 4321 glaze looks when fired to Seger 8. Certainly
> when fired to 2305F (at a ramp rate that makes cone 10 bend to 10
> o'clock and the tip of cone 9 touching the shelf) I have real crazing
> problems. Perhaps at a lower temp I wouldn't get crazing? That's sort
> of a Ron Roy question.
Probably a better question for folks who have fired that way, but
it would be interesting to hear Ron's "theoretical" ideas.
--
=3DA0Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
Robert Harris on mon 30 aug 10
It looks like I stand somewhat corrected, in that the cones aren't
quite as far apart as I remembered.
Seger Cone 8 to which Leach fired is quoted as 1250C in "A potter's
book" (2282F).
However I am now curious as to what the ramp rate (i.e. heatwork
equivalency) is for the quoted Seger temperatures. While Orton very
sensibly have different final temperatures for different ramp rates,
Seger only has a single table with no reference to ramp rate.
As I recall Leach had very long, wood, then oil, firings (24hrs+?
heating) so his final temperature might have been less even than
1250C. Or potentially we are examining the incorrect Orton table in
our direct comparisons.
I wonder how his 4321 glaze looks when fired to Seger 8. Certainly
when fired to 2305F (at a ramp rate that makes cone 10 bend to 10
o'clock and the tip of cone 9 touching the shelf) I have real crazing
problems. Perhaps at a lower temp I wouldn't get crazing? That's sort
of a Ron Roy question.
Any thoughts?
Robert
Ron Roy on mon 30 aug 10
Hi Douglas,
Not sure what your are getting at with this but - should not the
stoneware you are using for functional ware be fired at least high
enough to not leak - what ever cone that is?
RR
Quoting douglas fur <23drb50@GMAIL.COM>:
> others have pointed out sources that differ.
> What I would like to find out is how cones have come to differ when they
> started out with the same theoretical basis.
> I think the fact that leach's ^8 clear doesn't melt at ^ 10 for many is d=
ue
> to differing materials eg "podemore's water ground flint" vis american 32=
5
> mesh silica.
> Be that as it may, If the stoneware of leach/hamada is fired at a lower
> point say ^8/9 orton it would have a different character than stoneware
> fired at ^9/10. I think we americans tend to have a "more is better fire
> 'em flat" attitude and have drifted to higher temperatures which in itsel=
f
> is not wrong, but if we're to talk about "stoneware" we have to be clear
> about how we define the term.
> DRB
> Seola Creek
>
Lee Love on mon 30 aug 10
On Sun, Aug 29, 2010 at 5:47 PM, douglas fur <23drb50@gmail.com> wrote:
> =3DA0others have pointed out sources that differ.
> What I would like to find out is how cones have come to differ when they
> started out with the same theoretical basis.
I know Orton has adjusted it's cone formulas at least once.
> =3DA0Be that as it may, If the stoneware of leach/hamada is fired at a lo=
we=3D
r
> point say ^8/9 orton it would have a different character than stoneware
> fired at ^9/10.
Hamada fired oxidation in a large kiln with an nonuniform
temperature range. If you look at the published images of his work,
often the glazes are underfired. Traditionally, they used Kaki glaze
as a liner to seal unvitrified clay in the cold spots of the kiln.
When I first bought clay directly from the clay quarry, He was
very specific in making me understand that Mashiko Nami clay is only
fired to cone 8. That the Co-op Nami actually had higher alumina
Shigaraki Nami clay added to it, so it would fire to the modern cone
9/10 temperatures. He would get complaints from young potters
about the clay and advice about adding stuff to it to "make it
better." He said the modern potters were spoiled by bagged prepared
clays and did not understand natural materials and adjusting your
method to the materials.
--
=3DA0Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
ivor and olive lewis on tue 31 aug 10
Dear Eric Hansen
Where would Hermann Seger (1839-94) have obtained his frits?
It is my understanding that Herman Seger based his research on the Molecula=
r
Formula of Potash Felspar, using this as the prime ingredient together with
additions of other oxides.
The phenomenon of a slender Pyramid set at an angle bending when heated (du=
e
to pyroplasticity) became known as the Deformation Eutectic Point early in
the following century.
Singer and Singer, "Industrial Ceramics" provide several pages of
formulations for Deformation Eutectics based on natural minerals.
Regards,
Ivor Lewis,
REDHILL,
South Australia
Lee Love on tue 31 aug 10
On Mon, Aug 30, 2010 at 7:03 PM, Paul Herman w=
=3D
rote:
> resistant, and takes excessive heat well in the wood fire. Firing
> lower would not help, IMO.
And of course, glaze fit is always dependent upon the clay the glaze is put=
=3D
on.
--
=3DA0Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
Ron Roy on tue 31 aug 10
Hi Robert,
If the glaze is melted enough (all silica converted to amorphous) then
the expansion/contraction will be the same at all temperatures as far
as I understand this.
If there is still some quartz left as crystalline then that should
help keep the glaze in contraction as it cools through 573C
If the glaze is over fired - and the application not too thick - then
enough silica may be contributed by the clay body to alter the
expansion enough to lower expansion and prevent crazing - if the glaze
was close to not crazing to begin with.
I am now on my 524 dilatometer run - I am guessing that maybe 80 of
those runs were on glazes. Only one glaze showed any quartz inversion
and it was clearly underfired.
Not sure you wanted to know all that Robert - I feel this kind of
information is a great help to potters trying to understand the
clay/glaze relationship. I can't help wondering why it is not
presented in the great majority of pottery related books. No wonder so
many have problems understanding what to me is essential to success in
making functional ware.
RR
Quoting Robert Harris :
> It looks like I stand somewhat corrected, in that the cones aren't
> quite as far apart as I remembered.
>
> Seger Cone 8 to which Leach fired is quoted as 1250C in "A potter's
> book" (2282F).
>
> However I am now curious as to what the ramp rate (i.e. heatwork
> equivalency) is for the quoted Seger temperatures. While Orton very
> sensibly have different final temperatures for different ramp rates,
> Seger only has a single table with no reference to ramp rate.
>
> As I recall Leach had very long, wood, then oil, firings (24hrs+?
> heating) so his final temperature might have been less even than
> 1250C. Or potentially we are examining the incorrect Orton table in
> our direct comparisons.
>
> I wonder how his 4321 glaze looks when fired to Seger 8. Certainly
> when fired to 2305F (at a ramp rate that makes cone 10 bend to 10
> o'clock and the tip of cone 9 touching the shelf) I have real crazing
> problems. Perhaps at a lower temp I wouldn't get crazing? That's sort
> of a Ron Roy question.
>
> Any thoughts?
>
> Robert
>
Ron Roy on tue 31 aug 10
Hi Robert,
In reduction perhaps more silica would turn to amorphous - in that
case there would be less crystalline quartz to go through the
contraction at 573C and help keep a glaze in contraction. If the glaze
has crazed before that temperature is reached the quartz inversion
will not help of course.
Easy enough to fix the crazing Robert - especially if you have some
spodumene available. Just send me the recipe with the materials you
are using and I'll send you back a line blend that will eliminate it.
I just calculated it and the expansion is not that high - should be
easy to fix.
RR
Quoting Robert Harris :
> Hi Ron,
>
> What I specifically wanted to know (which you answered very well) was
> whether firing a glaze at a lower temperature would affect crazing.
>
> I have tried the 4321 glaze on 4 different clay bodies (that I can
> remember) and all crazed. It was not always directly visible unless
> you stained the crazes with India Ink (regular fountain pen ink etc
> does not work - presumably the particles are too large). This was true
> even when supplemented with 5% zircopax which one would expect to
> ameliorate crazing.
>
> I have met many potters that have used this +/- Zircopax as a liner
> glaze. I don't know whether the bodies I tested (2 from Axner and 2
> from Highwater) have a much higher COE or whether other potters use
> this as liner that crazes when examined thoroughly.
>
> In addition I should mention that I fire in an electric kiln (to +/-
> cone 10), but I cannot see how a reducing atmosphere would affect
> crazing. If it does does anyone know the mechanism?
>
> Robert
>
>
>
> On Tue, Aug 31, 2010 at 1:37 PM, wrote:
>> Hi Robert,
>>
>> If the glaze is melted enough (all silica converted to amorphous) then t=
he
>> expansion/contraction will be the same at all temperatures as far as I
>> understand this.
>>
>> If there is still some quartz left as crystalline then that should help =
keep
>> the glaze in contraction as it cools through 573C
>>
>> If the glaze is over fired - and the application not too thick - then en=
ough
>> silica may be contributed by the clay body to alter the expansion enough=
to
>> lower expansion and prevent crazing - if the glaze was close to not craz=
ing
>> to begin with.
>>
>> I am now on my 524 dilatometer run - I am guessing that maybe 80 of thos=
e
>> runs were on glazes. Only one glaze showed any quartz inversion and it w=
as
>> clearly underfired.
>>
>> Not sure you wanted to know all that Robert - I feel this kind of
>> information is a great help to potters trying to understand the clay/gla=
ze
>> relationship. I can't help wondering why it is not presented in the grea=
t
>> majority of pottery related books. No wonder so many have problems
>> understanding what to me is essential to success in making functional wa=
re.
>>
>> RR
>>
>>
>>
>>
>>
>> Quoting Robert Harris :
>>
>>> It looks like I stand somewhat corrected, in that the cones aren't
>>> quite as far apart as I remembered.
>>>
>>> Seger Cone 8 to which Leach fired is quoted as 1250C in "A potter's
>>> book" (2282F).
>>>
>>> However I am now curious as to what the ramp rate (i.e. heatwork
>>> equivalency) is for the quoted Seger temperatures. While Orton very
>>> sensibly have different final temperatures for different ramp rates,
>>> Seger only has a single table with no reference to ramp rate.
>>>
>>> As I recall Leach had very long, wood, then oil, firings (24hrs+?
>>> heating) so his final temperature might have been less even than
>>> 1250C. Or potentially we are examining the incorrect Orton table in
>>> our direct comparisons.
>>>
>>> I wonder how his 4321 glaze looks when fired to Seger 8. Certainly
>>> when fired to 2305F (at a ramp rate that makes cone 10 bend to 10
>>> o'clock and the tip of cone 9 touching the shelf) I have real crazing
>>> problems. Perhaps at a lower temp I wouldn't get crazing? That's sort
>>> of a Ron Roy question.
>>>
>>> Any thoughts?
>>>
>>> Robert
>>>
>>
>>
>>
>>
>
>
>
> --
> ----------------------------------------------------------
>
Robert Harris on tue 31 aug 10
Hi Ron,
What I specifically wanted to know (which you answered very well) was
whether firing a glaze at a lower temperature would affect crazing.
I have tried the 4321 glaze on 4 different clay bodies (that I can
remember) and all crazed. It was not always directly visible unless
you stained the crazes with India Ink (regular fountain pen ink etc
does not work - presumably the particles are too large). This was true
even when supplemented with 5% zircopax which one would expect to
ameliorate crazing.
I have met many potters that have used this +/- Zircopax as a liner
glaze. I don't know whether the bodies I tested (2 from Axner and 2
from Highwater) have a much higher COE or whether other potters use
this as liner that crazes when examined thoroughly.
In addition I should mention that I fire in an electric kiln (to +/-
cone 10), but I cannot see how a reducing atmosphere would affect
crazing. If it does does anyone know the mechanism?
Robert
On Tue, Aug 31, 2010 at 1:37 PM, wrote:
> Hi Robert,
>
> If the glaze is melted enough (all silica converted to amorphous) then th=
e
> expansion/contraction will be the same at all temperatures as far as I
> understand this.
>
> If there is still some quartz left as crystalline then that should help k=
eep
> the glaze in contraction as it cools through 573C
>
> If the glaze is over fired - and the application not too thick - then eno=
ugh
> silica may be contributed by the clay body to alter the expansion enough =
to
> lower expansion and prevent crazing - if the glaze was close to not crazi=
ng
> to begin with.
>
> I am now on my 524 dilatometer run - I am guessing that maybe 80 of those
> runs were on glazes. Only one glaze showed any quartz inversion and it wa=
s
> clearly underfired.
>
> Not sure you wanted to know all that Robert - I feel this kind of
> information is a great help to potters trying to understand the clay/glaz=
e
> relationship. I can't help wondering why it is not presented in the great
> majority of pottery related books. No wonder so many have problems
> understanding what to me is essential to success in making functional war=
e.
>
> RR
>
>
>
>
>
> Quoting Robert Harris :
>
>> It looks like I stand somewhat corrected, in that the cones aren't
>> quite as far apart as I remembered.
>>
>> Seger Cone 8 to which Leach fired is quoted as 1250C in "A potter's
>> book" (2282F).
>>
>> However I am now curious as to what the ramp rate (i.e. heatwork
>> equivalency) is for the quoted Seger temperatures. While Orton very
>> sensibly have different final temperatures for different ramp rates,
>> Seger only has a single table with no reference to ramp rate.
>>
>> As I recall Leach had very long, wood, then oil, firings (24hrs+?
>> heating) so his final temperature might have been less even than
>> 1250C. Or potentially we are examining the incorrect Orton table in
>> our direct comparisons.
>>
>> I wonder how his 4321 glaze looks when fired to Seger 8. Certainly
>> when fired to 2305F (at a ramp rate that makes cone 10 bend to 10
>> o'clock and the tip of cone 9 touching the shelf) I have real crazing
>> problems. Perhaps at a lower temp I wouldn't get crazing? That's sort
>> of a Ron Roy question.
>>
>> Any thoughts?
>>
>> Robert
>>
>
>
>
>
--
----------------------------------------------------------
Eric Hansen on wed 1 sep 10
"Seger's Ideal Flux" is always .3 potassium + .7 calcium. cone 6 for
example, would mean .06 alumina + 6.0 silica. These are melted
together then as a liquid, poured into water in which they shatter,
then are ground into the ceramic material & formed into a cone.
Without thus making the frit, every combination of materials concocted
to fulfill the afore mentioned Unity prescription will melt at a
different temperature. As are for example the anecdotal reports that
began this discussion thread, how each combination of raw materials
yields different results.
- h -
p.s. that is how it was described to me, anyway.
On Tue, Aug 31, 2010 at 2:26 AM, ivor and olive lewis
wrote:
> Dear Eric Hansen
>
>
>
> Where would Hermann Seger (1839-94) have obtained his frits?
>
> It is my understanding that Herman Seger based his research on the Molecu=
lar
> Formula of Potash Felspar, using this as the prime ingredient together wi=
th
> additions of other oxides.
>
> The phenomenon of a slender Pyramid set at an angle bending when heated (=
due
> to pyroplasticity) became known as the Deformation Eutectic Point early i=
n
> the following century.
>
> Singer and Singer, "Industrial Ceramics" provide several pages of
> formulations for Deformation Eutectics based on natural minerals.
>
>
>
> Regards,
>
> Ivor Lewis,
> REDHILL,
> South Australia
>
--
Eric Alan Hansen
Stonehouse Studio Pottery
Alexandria, Virginia
americanpotter.blogspot.com
thesuddenschool.blogspot.com
hansencookbook.blogspot.com
"To me, human life in all its forms, individual and aggregate, is a
perpetual wonder: the flora of the earth and sea is full of beauty and
of mystery which seeks science to understand; the fauna of land and
ocean is not less wonderful; the world which holds them both, and the
great universe that folds it in on everyside, are still more
wonderful, complex, and attractive to the contemplating mind." -
Theodore Parker, minister, transcendentalist, abolitionist (1810-1860)
Neon-Cat on fri 3 sep 10
Dear Robert,
I might ask if there is such a thing as a lot of pure amorphous silica
in a glaze?
What do you think?
And let me point out that with a glaze and a clay body that have
identical or near identical COEs the glaze may still craze.
Can you tell me why is this? If not, we will have a problem just
discussing this topic.
What is wrong with testing and adjusting glaze fit yourself on your
clay body, fired under conditions you work with?
Do you really need Ron to figure this out for you? While dilatometery,
per se, may be useful, I have some problems with the conclusions he
draws about clay science and how things work. If I go down to the drug
store and have the Dr. Scholls machine measure my foot size, what is
that going to tell me about the nature of my foot, its structure, the
percent bone or muscle in it, the health of my veins, how my skin will
fit to the foot, or worse, as Ron does with his assumed theories about
quantifying or qualifying cristobalite in a clay body, what will Dr.
Scholls=3DE2=3D80=3D99 measurement of my foot size tell me about my blood g=
lucose=3D
,
or blood pressure? See the problem I have when observations from a
tool designed to measure only linear expansion are used to formulate
theory about anisotropic systems that is then promoted to be true and
accurate because it is based on =3DE2=3D80=3D9Cscientific=3DE2=3D80=3D9D di=
latometric
measurements?
From what you have written on clayart it does not seem that you are
using glazes or clay bodies that are outside the norm for studio
potters and clay workers. How then would a dilatometery reading take
you to wondrous heights beyond those attained by successfully
adjusting your glaze using tried and true remedies?
Here is an article I found that illustrates how zinc oxide and zinc
vapor stay with a clay-ore-silica-calcium mix fired in heavy, heavy
reduction for the purpose of extracting the metal. Metal refiners
worked very hard to get zinc in useful, economically feasible amounts
and the remnant slag analyzed here is much like a glaze and is full of
zinc combined with something, quite often silica that forms silicates.
You don=3DE2=3D80=3D99t have to understand every term or every compound, I =
just w=3D
ant
you to see how busy a glaze, especially a complicated one, can be.
Microcracks (we see them resulting in crazing on our glazed work) can
form for a number of reasons causing the glaze to fail from the inside
out without regard to the clay body it covers or the COE of either
clay body or glaze.
One should look to operator error, too, when addressing crazing --
moisture absorption, firing practices, and glaze application being
three good areas to check.
=3DE2=3D80=3D9CThe Ceramic Process: A Manual and Source of Inspiration for =
Cerami=3D
c
Art and Design=3DE2=3D80=3D9D put out by the European Ceramic Work Centre a=
nd An=3D
ton
Reijnders, is an excellent and very easy-to-read book from 2005 with
reliable answers to many questions. I mention it because it is one
book I have and enjoy. In it a method is detailed that will give you a
rough estimate of the expansion rate of a clay body. Another section
tells you how to easily test for the moisture absorption propensities
(and the likelihood of crazing from this cause) of a glazed test
piece. The rest, like seasoning a recipe during cooking, you should be
competent to carry out. A firm grasp of basic principles will enable
you to figure out even seemingly complicated problems but the basics
have to be founded in reality as is commonly accepted and used to get
us to the moon, deep under the sea, and down the street in our cars so
we can get to the next potter party.
The Canadian Mineralogist, Vol. 39, pp. 873-888 (2001)
PRIMARY PHASES AND NATURAL WEATHERING OF OLD LEAD=3DE2=3D80=3D93ZINC
PYROMETALLURGICAL SLAG FROM P=3DCB=3D87R=3DC3=3D8DBRAM, CZECH REPUBLIC
VOJT=3DCB=3D87ECH ETTLER
http://geologia.fc.ul.pt/Aulas/RMIA/docs/ProdutosPirometalurgia.pdf
Look also at photos of Metallurgical Slag from Roosevelt, Washington,
first if you=3DE2=3D80=3D99ve never seen slag =3DE2=3D80=3D93 it looks pret=
ty much like=3D
pictures
of glaze =3DE2=3D80=3D93 just scroll through and look at pics. There=3DE2=
=3D80=3D99s ev=3D
en a pic of
dendritic iron oxide in the slag matrix (glassy interior area).
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2004-5090
Vertical Distribution of Trace-Element Concentrations and Occurrence
of Metallurgical Slag Particles in Accumulated Bed Sediments of Lake
Roosevelt, Washington, September 2002
http://pubs.usgs.gov/sir/2004/5090/section6.html
Our glazes and clay bodies are very active as they are fired and
cooled. We should begin to form better mental images of just what is
taking place when we fire a kiln full of ware. You are free of course
to pursue your own direction but please tell me why you are so
determined to defend certain positions and personalities that would
limit forward thinking by others? This just does not seem like a good
example to set now or for the future.
There is first rate information available for us if we are discerning
and thoughtful in our choices of material to read and thoughtful about
how we employ the ideas and concepts offered. Just because an idea or
statement is published in a book or posted on a web site or on a chat
list does not automatically guarantee either truthfulness or accuracy.
Verify information by checking a number of sources. If a process is
widely accepted and used in industry, medicine, or other current
technology, the chances are that your material is correct. Try to find
reliable sources. Non-science-based sites may echo and amplify an
error until one begins to accept something as true that is not, so it
is prudent to watch which sources one is using and trusting.
And Robert =3DE2=3D80=3D93 there is so much bs on list at times that one co=
uld be
driven to distraction just reading it all. Seldom do you all label
these long drawn out threads and over-worked ideas, much less an
individual poster as being non-constructive. So, what? You don=3DE2=3D80=3D=
99t li=3D
ke
cats? We can and often do think for ourselves, study up on our basics,
schmooze a little from time-to-time, enjoy creative artistic bursts,
and generally take great pleasure in life and alternate opinions. Must
I flow along down dead-end streets just because you think that is the
way I should go? I=3DE2=3D80=3D99d leap a fence and head my own way before =
accept=3D
ing
some things. Or I=3DE2=3D80=3D99d take a stand on important issues if I fel=
t it w=3D
as
warranted.
Yes, poor interpretation does seem to be an issue.
Just for the record -- it is ideas and concepts I question and take
issue with sometimes =3DE2=3D80=3D93 never persons or personalities.
Marian
neoncat
Neon-Cat on fri 3 sep 10
Ron wrote: "I am now on my 524 dilatometer run =3D96" (snip and
continuing) "I feel this kind of information is a great help to
potters trying to understand the clay/glaze relationship. I can't help
wondering why it is not presented in the great majority of pottery
related books."
Probably because almost a hundred years ago it was known that there
are some serious drawbacks to your approach that deals only with the
coefficient of expansion differences between clay body and glaze
without understanding what is created during the glaze firing of a
piece. Dilatometric analysis, difficult at best, can offer only
partial information regarding glaze fit and the possibilities that a
glaze may craze.
From a 1912 article written in the journal of The American Ceramic Society:
"Crazing is due to shrinkage in volume and to surface tension. Strains
must certainly arise from this drawing up of the glaze and these can
find relief only in the cracking of the glaze. The shrinkage in volume
of the mass due to changes in mineral constitution and the volume
changes which these newly formed minerals pass through when cooling
after having attained rigidity, we consider as being sufficient to
account for all the strains necessary to produce crazing. We need not
resort to the untenable supposition of there being differences in
coefficient of expansion and contraction between the body and the
glaze to account for these glaze defects."
Scientists and astute clay workers and authors of ceramic texts now
know much more than was possible 20, 30, and 40 years or more ago and
some low-tech books do address crazing from an alternate perspective
while high-tech books have left dilatometery totally in the dust. Many
very good books available to potters and clay workers provide the
tried and true traditional methods for remedying crazing and these
anyone may successfully utilize without having to resort to
dilatometery.
Marian
neoncat
www.neon-cat.com
Robert Harris on fri 3 sep 10
Marian,
As someone who seems to have a respect for science I am surprised that
you are so scathing about the only practical experimental test we have
available to us. While I am sure you are correct that there are more
accurate measures, these are not going to be available to anyone
outside a serious research institution - who are unlikely to be useful
to a studio potter. While dilatometry may have its drawbacks it is at
least one way of measuring what is happening. As far as I am aware
there are no other reasonable ways of getting ANY information other
than simple trial and error (your "tried and true traditional methods
for remedying crazing"). At least dilatometry gives us SOME
information.
From my perspective it is like disparaging pH strips. Sure they only
measure pH in a small range, and pretty inaccurately at that, but
they're a lot cheaper than a $200+ pH meter and sometimes all you need
is to figure out whether your solution is highly acid, highly alkaline
or neutral. As long as you are fully aware of the drawbacks (and I'm
sure Ron Roy is) at least dilatometry gives us some easily accessed
information.
Frankly unless you would like to give us some specifics on what other
measurements (and how) we can make, I feel that your criticisms are
nonconstructive. Frankly there is rarely such a thing as "bad"
information, just poor interpretation.
Robert
ivor and olive lewis on sat 4 sep 10
Dilatometers I know about. For three years my task (circa 1955), as a lab
technician was to use and maintain a mechanical Chevenard Dilatometer to
ascertain those temperatures at which steel samples passed through phase
transition points as they were cooled. How nice it would have been to use a=
n
electronic devise similar to that at Ron's deposal.
One situation which plagued me almost thirty years ago when I was using
recipes from compilations and ceramic magazine was the improbability of
making pottery that did not craze. Fortunately I was never cursed by
Shivering. However, because I was working in stoneware and firing to Orton
Cone 8 and higher the clays I used were always vitrified so leaking or
weeping were not issues. The crunch came when a kiln load of pots went into
self destruct mode.
The problem was solved empirically, by making an assumption about the
mineral in the glaze which was responsible for a high Thermal Linear
Coefficient, then line blending this ingredient with a series of minerals
known to alleviate the problem. The sample whose proportions showed the
lowest incidence of crazing, as revealed by dye penetration testing, was
selected for further testing. This enabled me to achieve a basic transparen=
t
colourless glaze and many other craze free glazes that have worked well
since that time.
It would not take a lot of ingenuity to construct apparatus to measure the
Thermal Linear Coefficients of glaze and ceramic samples. Nor is there need
to test at very high temperatures. Those who have MC6G can, if they wish,
use the graphs to calculate Thermal Linear Coefficients.
I was not impressed by the unbattributed quotation from a 1912 article
written in the journal of The American Ceramic Society:
Best regards,
Ivor Lewis,
REDHILL,
South Australia
John Hesselberth on sat 4 sep 10
On Sep 3, 2010, at 9:23 PM, Neon-Cat wrote:
> Scientists and astute clay workers and authors of ceramic texts now
> know much more than was possible 20, 30, and 40 years or more ago and
> some low-tech books do address crazing from an alternate perspective
> while high-tech books have left dilatometery totally in the dust.=3D20
Hi Marian,
In addition to the excellent response by Robert Harris I would like to =3D
add a couple points.
In my "real job", from which I am happily retired, I used to be =3D
responsible for the work of several hundred engineers and scientists. I =3D
had responsibility for all the technical work from basic research =3D
through support to manufacturing operations for DuPont's nylon business. =
=3D
While one can never put that many people into two boxes I am going to =3D
try for the purpose of making a point. I found that among those people =3D
there were those who liked to solve problems and those who preferred to =3D
extend knowledge. They did not break down cleanly between scientists and =
=3D
engineers--there were some of each with both types of training.
Those who were problem solvers used whatever tool was appropriate to =3D
quickly solving a problem whether or not it represented the latest =3D
technology. In fact I would say they rarely used the latest technology, =3D
not because they weren't familiar with it, but because it often had not =3D
really been proven useful or was far more expensive than was needed to =3D
solve the particular problem they were working on. And as for the peer =3D
reviewed literature, it is often rather esoteric and sometimes pure =3D
garbage. Sorting the useful from the interesting but not very useful in =3D
the scientific literature is often a herculean task. The problem solvers =
=3D
usually found handbooks (like Perry's Handbook for chemical engineers), =3D
textbooks, and the patent literature far more useful than journal =3D
articles. Those 3 sources usually contain time-tested technology.
Those who wanted to extend knowledge where enamored by the latest tools =3D
and lobbied long and hard to add them to our laboratories or start =3D
relationships with universities or others who were developing those =3D
tools. Those people would occasionally make the major breakthroughs or =3D
inventions. In an industrial setting their contributions were fewer and =3D
farther between, but when they made them they were usually large. =3D
Without those people nylon and lots of other polymeric products would =3D
never have been invented by DuPont. Without the problem solvers they =3D
would never have been commercialized.
I would suggest Ron is a problem solvers and, since I know him =3D
personally, a darn good one. His use of dilatometry is entirely =3D
appropriate in my view. By the way dilatometers are still widely =3D
available for sale. Someone other than Ron must still be using them. To =3D
imply he is not an astute clay worker is a smear I cannot let pass. I =3D
think your interests lie more in the knowledge extension area and, =3D
hence, you are more interested in the latest tools. That is a perfectly =3D
valid area of interest, but I would suggest you learn to appreciate the =3D
problem solvers, and their different way of working, also.
Regards,
John
John Hesselberth
john@frogpondpottery.com
phil on sun 5 sep 10
Hi John,
Just as an aside, meant friendly -
I think it would be more fair to say
that Nylon was invented by Wallace Caruthers, who had envisioned critical
details of inviting long chain Polymers to occur on request, years before,
and was
interested to find a
practical means of producing what would later be called 'Nylon' for Textile
and other application well prior to
working for Dupont's experimental Labratory on Salary.
Dupont supported his endevors by essentially offering a research position, =
a
setting, a small staff, and leaving him alone to do his work, in order to
obtain a patent and manufacturing monopoly on whatever results he might
create.
Nice image of what research 'Science' used to look like -
http://upload.wikimedia.org/wikipedia/commons/6/64/Julius_Nieuwland.jpg
Image shows the Labratory of Julius Nieuwland, a Scientist Priest ( hence
the garb, ) who pioneered the development of what was later to be called
'Neoprene', which if memory serves, Caruthers was involved in overseeing at
Dupont.
Anyway...
Endless...
Phil
Lv
----- Original Message -----
From: "John Hesselberth"
On Sep 3, 2010, at 9:23 PM, Neon-Cat wrote:
> Scientists and astute clay workers and authors of ceramic texts now
> know much more than was possible 20, 30, and 40 years or more ago and
> some low-tech books do address crazing from an alternate perspective
> while high-tech books have left dilatometery totally in the dust.
Hi Marian,
In addition to the excellent response by Robert Harris I would like to add =
a
couple points.
In my "real job", from which I am happily retired, I used to be responsible
for the work of several hundred engineers and scientists. I had
responsibility for all the technical work from basic research through
support to manufacturing operations for DuPont's nylon business. While one
can never put that many people into two boxes I am going to try for the
purpose of making a point. I found that among those people there were those
who liked to solve problems and those who preferred to extend knowledge.
They did not break down cleanly between scientists and engineers--there wer=
e
some of each with both types of training.
Those who were problem solvers used whatever tool was appropriate to quickl=
y
solving a problem whether or not it represented the latest technology. In
fact I would say they rarely used the latest technology, not because they
weren't familiar with it, but because it often had not really been proven
useful or was far more expensive than was needed to solve the particular
problem they were working on. And as for the peer reviewed literature, it i=
s
often rather esoteric and sometimes pure garbage. Sorting the useful from
the interesting but not very useful in the scientific literature is often a
herculean task. The problem solvers usually found handbooks (like Perry's
Handbook for chemical engineers), textbooks, and the patent literature far
more useful than journal articles. Those 3 sources usually contain
time-tested technology.
Those who wanted to extend knowledge where enamored by the latest tools and
lobbied long and hard to add them to our laboratories or start relationship=
s
with universities or others who were developing those tools. Those people
would occasionally make the major breakthroughs or inventions. In an
industrial setting their contributions were fewer and farther between, but
when they made them they were usually large. Without those people nylon an=
d
lots of other polymeric products would never have been invented by DuPont.
Without the problem solvers they would never have been commercialized.
I would suggest Ron is a problem solvers and, since I know him personally, =
a
darn good one. His use of dilatometry is entirely appropriate in my view. B=
y
the way dilatometers are still widely available for sale. Someone other tha=
n
Ron must still be using them. To imply he is not an astute clay worker is a
smear I cannot let pass. I think your interests lie more in the knowledge
extension area and, hence, you are more interested in the latest tools. Tha=
t
is a perfectly valid area of interest, but I would suggest you learn to
appreciate the problem solvers, and their different way of working, also.
Regards,
John
John Hesselberth
john@frogpondpottery.com
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