crystalline glazes

updated tue 1 may 12

grevans@cencom.net on tue 12 mar 96

Looking for cone 9-10 crystalline glazes to test. Will post results.

Gregory Evans
grevans@cencom.net

Hakan Dakin on wed 13 mar 96

Hi Gregory,

if you like to work with ferro frits here is the basic recipe for
crystalline glazes. i use it for my thesis project:

Cone 8-9 oxidation

ferro frit 3110 48
ZnO 28
Silica 18
Ti02 5
Epk 1


(Soaking at cone 1 for 3 hours)

On Tue, 12 Mar 1996 grevans@cencom.net wrote:

> ----------------------------Original message----------------------------
> Looking for cone 9-10 crystalline glazes to test. Will post results.
>
> Gregory Evans
> grevans@cencom.net
>

Paula Coleman on mon 17 jun 96

I have been working with crystalline glazes for a while and getting
radically different results from the interior of the pot to the exterior of
the pot. The inside generally shows the best crystal growth and color,
while the outside is a bit boring. Does anyone know why this happens, and
how I could create beautiful crystals on the outside of the pot as well?

Paula

LEE on tue 18 jun 96

Perhaps the inside of the pot is cooling slower than the outside.
Sounds like you should try a longer, slower cooling cycle to enhance
your outside surfaces.

Ron Roy on tue 18 jun 96

>----------------------------Original message----------------------------
>I have been working with crystalline glazes for a while and getting
>radically different results from the interior of the pot to the exterior of
>the pot. The inside generally shows the best crystal growth and color,
>while the outside is a bit boring. Does anyone know why this happens, and
>how I could create beautiful crystals on the outside of the pot as well?
>
>Paula

Hi Paula,

The slower the glaze cools the bigger the crystals get which explains why
they are growing more on the inside. I don't know what kind of crystals
grow best at what temperatures but you can find out by slowing down your
cooling till you get what you want. Once you find out where they grow best
you can even refire to that temperature and they will grow more. Having a
kiln controller which allows you to ramp down will be a big help. I have
read that a soft bique refire (cone 08 ?) will help crystal growth.

A friend (Diane Creber) has written a book on crystaline glazes and it is
being published. Axners will have it sooner or later.

Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849

Barnstudio Howard on tue 18 jun 96

Paula,
I am pretty sure that the reason that the crystals in side are more
intresting than the outside is that the inside cools alot slower. This is my
experience. The Crystals need to develop, and they develop in the cooling
cycle, at the end of your firing. After the kiln has shut off/turn off, I
let the kiln cool with the top peep hole closed and it will cool very slowly,
the only problem with this is that you have to wait alittle(alot) longer than
usual. You also have to be confident that you have let the glazes mature and
melt properly. Try that and see if it helps, you should get Crystals all
over the place.

And no peeking while cooling

Earl

John Baisch on fri 19 jul 96

Hello All,

Does anyone have a good Cone 5-6 recipe for
Crystalline Glazes... ? I also would like
some ideas in technique for firing/soaking
the pieces...?

But wait! while we are at it what about a good
suggested claybody for the crystalline process...?

Thanks much,

JB
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~ John Baisch ~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~ E-Mail: jbaisch@micron.net ~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

David Hewitt on sun 21 jul 96

Hello John,
I do not have experience with crystalline glazes but I do know of an
excellent article that appeared in Ceramic Review No.137 (Sept/Oct 1992)
by Derek Clarkson.
His recipes are all based on the following approximate percentages:-
50 Ferro Frit 3110
25 Zinc Oxide
20 Flint
5 Titanium Dioxide
1 China Clay and/or Alumina
Colouring Oxides - cobalt, copper and manganese most often used,
followed by iron and nickel.
The article gives ten specific recipes around the above with colour
illustrations to show the very dramatic crystal effects.
For each of these examples the article also gives the firing details of
the times of crystal growing periods and the diameter of the largest
crystal.
There is also a mass of detail on the application of the glazes with
copious illustrations.
Derek Clarkson says that Porcelain bodies are the most suitable. White
stoneware bodies can also be used but the crystals are smaller.
If you are unable to get sight of a copy of this article please contact
me by e-mail if you want further information.

David Hewitt
David Hewitt Pottery Caerleon, Newport, Gwent, UK.
URL http://digitalfire.com/magic/hewitt.htm

Shelly Christensen on mon 4 nov 96

-- [ From: Shelly Christensen * EMC.Ver #2.5.02 ] --

Hi again. It's been a while since I've written in. Too much to do and too
little time.
I have been experimenting with crystalline glazes and have a few results.
Colors seem rather cream.that's ok, nice soft buttery texture. that's ok,
but crystals are rather small. I fired to 2360, lowered the temp to 1950,
raised it back to 2000 and held for 3 hours. Using the recipes found in an
old ceramics book about crystalline glazes.
Does anyone out there have any good recipes for this process for cones 8-10,
and any suggestions for growing larger crystals? If I increase the soak
time more, will this help? I have tried to retrieve data from the clayart
database with no luck. Any suggestions?
TIA
Shelly Christensen
claywork@magiclink.com

Katherine Villyard on wed 6 nov 96

On Mon, 4 Nov 1996, Shelly Christensen wrote:

> ----------------------------Original message----------------------------
> I have been experimenting with crystalline glazes and have a few results.
> Colors seem rather cream.that's ok, nice soft buttery texture. that's ok,
> but crystals are rather small. I fired to 2360, lowered the temp to 1950,
> raised it back to 2000 and held for 3 hours. Using the recipes found in an
> old ceramics book about crystalline glazes.

I was never really a huge crystal glaze gal, but one of my profs was and
I got the impression from her that you might need to hold the kiln longer
or reduce alumina. FWIW.


Katherine in Denton, Texas

DonKopy@aol.com on thu 7 nov 96

Shelly Christensen wrote:
snip>I have been experimenting with crystalline glazessnip>but crystals are rather small. I fired to 2360, lowered the temp to
1950,
raised it back to 2000 and held for 3 hours.Any suggestions?

Hi Shelly,
I'm wondering why you dropped the temp to 1950 then raised it again? You
might try just holding at 2000* without that dip in the profile. Controllers
are *a must* if you expect any kind of repeatable results with this type of
glaze.

Here are some factors which will effect macrocrystalline development:

1-A base glaze formula having from .3-.7moles of ZnO with the balance usually
made up of KNaO (though Parmelee notes all RO's of a low M.W. particularly
LiO as helpful) usually provided in fritted form. It seens that .5-.65 moles
of ZnO is the most common.
The Alumina should be kept from 0 to .25 moles with .05 most typical.
The Silica should be kept between 1.75 - 2.20 moles.

2- Additions of 7-10% titanium dioxide will assist in crystal development
often with an additional .5 - 2% rutile added as a seeding agent to assist in
crystal nucleation.

3- High mobility and fluidity of the glaze is essential. Anyone attempting
this should be aware of the stilting requirements of such ware before
proceeding. (Catch basins, pot supports, etc....). Generally these type
glazes are applied very thickly and you can expect a lot of it to flow right
off the pot.

4- Each crystalline glaze has a zone of nucleation and a zone of
crystallization the first where the crystals first form, the second where
they grow. Finding that zone for your glaze is a key to controlling crystal
growth. These zones typically lie in the upper end of the 2025* to 1500*F
range with 2012 most often quoted (wondering if this is just out of
convenience and rounding as this is a exactly 1100*C). You may get a
different type, size, and shape of crystals depending on how long is spent at
a certain temp. The longer the time spent in the zone of nucleation, the
greater the quantity of crystals developed; the longer in the zone of
crystallization, the greater the growth of individual crystals.

5- Clay body has a big effect on crystals with a porcelain body being the
most benificial.

6- The peak temp should be reached rather quickly for best cycle. Norton
recommends reaching cone 10 in an hour! This said, one would assume the
faster you fully melt the glaze the better, then quick cooling to the
crystallization temp.(usually near 2000*F) and holding there for a period of
from 3 to 6 hours. The longer the time spent in the higher range, the greater
the interaction between the body and the glaze, introducing more alumina into
the mix, retarding crystal development.

7- Highly fritted compositions seem to work the best. It has been suggested
that the best development of those spectacular large crystals may be best had
by fully fritting the composition first (not practical in most studio
settings but it is noted in the literature as being benificial).

8- One approach to assure hitting the zone for your particular glaze is to
fire to peak temp., crash cool to 2050*F then take from 4 to 7 hours to cool
down to 1500* (This is close to the cycle used by David Snair in his CM
article ...early 80's??)

9- I have been told by some that particle size of the frit plays a part and
spoke to one crystal grower who routinely seived his frit through a 200 mesh
before using it. Perhaps using a very fine silica may help as well.

10- Most crystals are grown in a neutral atmosphere (electric kilns- perhaps
due to the ease of controlling them with the appropriate devices). I have
read reports of reduction as well, this would probably have to be done on the
cooling cycle to effect a color shift after the crystals have been formed. I
know that reduction and zinc are a bad combination, so I wonder about this.

So...... some of the most spectacular crystal development (those large 6"
dia. ones) may be attributed to the use of an extremely fast and complete
melt, a fully fritted glaze batch, and an exacting cooling schedule (using an
exacting controller and high quality pyrometry) calculated to reduce the
quantity of crystals had, and to optimize their size by a long soak of up to
6 hrs. in their target zone.

Read the following:
Glazes for Special Effects - Herbert Sanders
Contemporary Ceramic Formulas - Conrad
Ceramic Glazes - Parmelee
Elements of Ceramics - Norton
The Snair article in CM

Now itching to grow crystals,
and really glad not to be living in the era of cam driven controllers,
but..... still throwing Christmas orders,

Don Kopyscinski
Bear Hills Pottery
Newtown, CT

Who *really hates*........ to see the best crystals in the catch basins.

74134.2672@CompuServe.com
or
DonKopy@AOL.com

Brad Sondahl on mon 13 jan 97

Dan & Jannine Ishler wrote:
>
> ----------------------------Original message----------------------------
> I am trying to collect information about crystalline glazes. I would
> like to talk to you, about the type of zinc to use. Batch size is
> another question I have.
I use Phillips process raw zinc oxide, obtainable from Minnesota Clay.
Years ago I found that the calcined zinc available from Seattle Pottery
caused pinholing in otherwise reliable glaze. This runs counter to
conventional wisdom. I don't know why you are interested in batch
size. Batch size is what fits in the bucket. Here's a pale green cone
10 zinc Crystalline glaze under development. I fire oxidation.
Sondahl's 99 green crystalline
Frit P25 28.796
Zinc oxide 25.654
Flint 13.089
Custer feldspar 23.037
Whiting 3.141
Copper carbonate 1.047
Cobalt carbonate 0.524
Rutile 1.047
Kaolin 2.618
Titanium dioxide 1.047
This is not as runny as most crystalline glazes, but it's well to fire a
sample in a basin, and allow 1 cm clearance on the bottoms. When
underfired the glaze is matte, without crystals. I do not soak to
produce crystals, they will grow to 2 cm or more in a regular electric
firing when cone 10 is reached.
I am interested in discussing crystalline glazes with others also. They
have not made me rich to date.

Brad Sondahl in Idaho
bsondahl@camasnet.com

Bill Amsterlaw on mon 13 jan 97

Hi Clayart:

Someone asked about crystalline glazes a few days ago. There is a 10-page
section on this topic in the latest issue of Studio Potter (December 1996) pp.
39-49.

- Bill Amsterlaw (wamster@msn.com)
Plattsburgh, NY

CP Dunbar on tue 4 mar 97

"Someone asked about crystalline glazes a few days ago. There is a
"10-page
"section on this topic in the latest issue of Studio Potter (December
"1996) pp.
"39-49.

"- Bill Amsterlaw (wamster@msn.com)
" Plattsburgh, NY

Is there a way to get a reprint of these pages or whatever ?
Would appreciate any reply.
cp




--
"And she shall have music wherever my Lady goes."

cpdunbar@concentric.net

Bill Amsterlaw on wed 5 mar 97

CP Dunbar requested information on how to obtain a reprint of the discussion
on crystalline glazes in Studio Potter (Dec 96): 25:1, 39-49.

The publisher's address is:

Studio Potter
Box 70
Goffstown, NH 03045
603-774-3582


- Bill Amsterlaw (wamster@msn.com)
Plattsburgh, NY

Ron Roy on thu 6 mar 97

>----------------------------Original message----------------------------
>"Someone asked about crystalline glazes a few days ago. There is a
>"10-page
>"section on this topic in the latest issue of Studio Potter (December
>"1996) pp.
>"39-49.
>
>"- Bill Amsterlaw (wamster@msn.com)
> " Plattsburgh, NY

There is also an article in the current Ceramics Technical (#3 1996)

Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849

Jan Adams on fri 21 mar 97

------------------
I have recently become accustomed to checking through messages a couple of
times a week. Observations have been interesting and much of what I have =
come
upon has been helpful. I've learned to watch closely for a few names that
always seem to have useful information to share.
I have read thoroughly all sources I have found on crystalline glazes,
including latest issue of =22Studio Potter=22, as well as Robin Hopper. I =
knew to
expect difficulty and fluid glazes, and I have. I would certainly =
appreciate
any sage advice. I used a typical glaze, Ferro Frit 3110, zinc, flint,
titanium, etc. and fired to a =5E10 and most of the glaze ended up on =
shelves
which I had carefully prepared. I did see a few small but beautiful =
crystals
gathered around the bases of the pieces and also a few inside. My venting
system uses an inline venting fan designed for electric stoves and I am
particularly curious as to whether crystalline glazes, or any glazes for =
that
matter, may be affected by too much air movement in the kiln. I welcome any
suggestions or discussion.

Jan in beautiful N.C.,
where Tom Gray
has his wonderful clay website

Brad Sondahl on sat 22 mar 97

My experience with crystalline glazes (check the results on my webpage).
If underfired, the glaze is sugary and dark. If fired to the exact
temperature, with up to 5% kaolin, the glaze runs about 1/4 inch (make
sure to wax a 1/2 inch ring at the bottom--any irregularity in the
waxing invites a drip. If overfired, the glaze runs off the pots, no
crystals. I think this is because the glaze gets too thin. Make sure
your application is thick enough. Try the glaze in different locations
to find where your hot/cold spots are.
I fire to a low cone 10, let the kiln shut off and coast, with no
soaking. My kiln gases are vented with a passive steel pipe chimney (and
the kiln room additionally vented with a fan).
--
Brad Sondahl
bsondahl@camasnet.com
http://www.camasnet.com/~asondahl
PO Box 96, Nezperce ID 83543

Marc A. Baker on mon 9 jun 97

hi everyone. i have been working with crystalline glazes for many
years, mostly high fire cone 10. recently i have been looking
into trying some c. glazes that are cone 6 or lower. does anyone
know any base glazes or book resources? also i recently saw the
c. monthly issue with a writeup on crystalline- showing a red glaze
bowl-it was great. anyone know how to produce a red crystalline
glaze in an electric kiln? hope all are enjoying this beautiful
day.
marc baker

Marc Kiessling on tue 10 jun 97

Greetings Marc & Clayart:

Here is a list of some articles that may be of interest to all regarding
crystalline glazes:

Regarding the red glaze in C.M. Check out "The Studio Potter, Dec'96,
Vol #25, number 1, pg 39-49". Enough to make your eyes water (me anyway).

Also have a look at "Ceramics Technical, Nov'96, #3, pg 15-21" (new sister
publication to Ceramics Art and Perception). Only 3 issues old; comes out
twice a year, but great so far. No reds but lots of ideas.

Have a look at the cover article of " Ceramics Monthly, April'97 " A Wang
Chun Wen creates some wonderful iron crystals in reduction and neutral
atmospheres.

An article was advertised in the back of C.M. some time ago that sells
for around $12.00 U.S. The potters name is Dan Turnidge. He can be reached at
River Rock Clay Co., P.O. Box 3183, Salem, Oregon, 97302,Phone (503)
581-3606.
It is a great little paper. He seems to know his stuff. He covers the whole
firing of crystals; ie. recipes, chemicals, colourants, firing schedules,
etc.
There is a list of recipes covering the temperature range from cone 6-10.

Regards,

Marc Kiessling
" CONE10CRY@aol.com "

ps. Marc, I'm sending you the above plus a personal note on crystals.

Carol Jackaway on wed 11 jun 97

Hi all,
I was told that if I take a glaze, pour it onto a cookie sheet, let it
dry then break it up, these peices will act as crystals in a commercial
glaze. True or False?
Thanks,
Carol
CoilLady
Sunny and 80 finally!!!!!!!

Nancy Rogers on thu 12 jun 97

Greetings Marc:
My friend and I are very interested in crystalline glazes and have signed up
for the workshop on same at Halliburten next May. Can you tell me how to go
about getting copies of the articles mentioned below. I have the CM from
April 97 but am unfamiliar with the others.
<< "The Studio Potter, Dec'96, Vol #25, number 1, pg 39-49". Enough to make
your eyes water (me anyway).>>
<sister
publication to Ceramics Art and Perception). Only 3 issues old; comes out
twice a year, but great so far. No reds but lots of ideas.>>

Thanks.
Nancy, the Cracked Potter in Hershey, PA
GoneTwoPot@aol.com

Regarding the red glaze in C.M.
An article was advertised in the back of C.M. some time ago that sells
for around $12.00 U.S. The potters name is Dan Turnidge. He can be reached at
River Rock Clay Co., P.O. Box 3183, Salem, Oregon, 97302,Phone (503)
581-3606.
It is a great little paper. He seems to know his stuff. He covers the whole
firing of crystals; ie. recipes, chemicals, colourants, firing schedules,
etc.
There is a list of recipes covering the temperature range from cone 6-10.
>>

Malone & Dean McRaine on sat 18 oct 97

Aloha all:
Check out this website for some great ^10 crystal glazes

http://www.barra.se/stoneware/english/engelsketta.htm

recipes included.
Dean

Leon Popik on fri 7 nov 97

A book I would recommend for trying out Crystalline Glazes would be "The
Ceramic Spectrum" by Robin Hopper.
He gives a number of recipes at different temperatures and talks a little
about characteristics. I tried most of the recipes myself and found the
ones that worked best were mixtures from line blends. I fired to cone 9
reduction, just make sure to have something underneath just in case they
run, since that is one characteristics.

Good Luck
Leon

DonKopy@aol.com on fri 7 nov 97

Hi Everyone,

Bill Amsterlaw was kind enough to forward a copy of my earlier post on zinc
silicate (willemite) crystals. I repost it here for those interested in
growing crystals.
---------------------------------------------------
Here are some factors which will effect macrocrystalline development:

1-A base glaze formula having from .3-.7moles of ZnO with the balance
usually made up of KNaO (though Parmelee notes all RO's of a low M.W.
particularly LiO as helpful) usually provided in fritted form. It seens
that .5-.65 moles of ZnO is the most common. The Alumina should be kept
from 0 to .25 moles with .05 most typical. The Silica should be kept
between 1.75 - 2.20 moles.

2- Additions of 7-10% titanium dioxide will assist in crystal development
often with an additional .5 - 2% rutile added as a seeding agent to assist
in crystal nucleation.

3- High mobility and fluidity of the glaze is essential. Anyone attempting
this should be aware of the stilting requirements of such ware before
proceeding. (Catch basins, pot supports, etc....). Generally these type
glazes are applied very thickly and you can expect a lot of it to flow
right off the pot.

4- Each crystalline glaze has a zone of nucleation and a zone of
crystallization the first where the crystals first form, the second where
they grow. Finding that zone for your glaze is a key to controlling crystal
growth. These zones typically lie in the upper end of the 2025* to 1500*F
range with 2012 most often quoted (wondering if this is just out of
convenience and rounding as this is a exactly 1100*C). You may get a
different type, size, and shape of crystals depending on how long is spent
at a certain temp. The longer the time spent in the zone of nucleation, the
greater the quantity of crystals developed; the longer in the zone of
crystallization, the greater the growth of individual crystals.

5- Clay body has a big effect on crystals with a porcelain body being the
most beneficial.

6- The peak temp should be reached rather quickly for best cycle. Norton
recommends reaching cone 10 in an hour! This said, one would assume the
faster you fully melt the glaze the better, then quick cooling to the
crystallization temp.(usually near 2000*F) and holding there for a period
of from 3 to 6 hours. The longer the time spent in the higher range, the
greater the interaction between the body and the glaze, introducing more
alumina into the mix, retarding crystal development.

7- Highly fritted compositions seem to work the best. It has been suggested
that the best development of those spectacular large crystals may be had by
fully fritting the composition first (not practical in most studio
settings but it is noted in the literature as being beneficial).

8- One approach to assure hitting the zone for your particular glaze is to
fire to peak temp., crash cool to 2050*F then take from 4 to 7 hours to
cool down to 1500* (This is close to the cycle used by David Snair in his
CM article ...early 80's??)

9- I have been told by some that particle size of the frit plays a part and
spoke to one crystal grower who routinely sieved his frit through a 200
mesh before using it. Perhaps using a very fine silica may help as well.

10- Most crystals are grown in a neutral atmosphere (electric kilns-
perhaps due to the ease of controlling them with the appropriate devices).
I have read reports of reduction as well, this would probably have to be
done on the cooling cycle to effect a color shift after the crystals have
been formed. I know that reduction and zinc are a bad combination, so I
wonder about this. So...... some of the most spectacular crystal
development (those large 6" dia. ones) may be attributed to:
-the use of an extremely fast and complete melt
-a fully fritted glaze batch
-an exacting cooling schedule (using an exacting controller and high quality
pyrometry) calculated to reduce the quantity of crystals had, and to
optimize their size by a long soak of up to 6 hrs. in their target zone.
-using a glaze with a very high mobility

Read the following:
Glazes for Special Effects - Herbert Sanders
Contemporary Ceramic Formulas - Conrad
Ceramic Glazes - Parmelee
Elements of Ceramics - Norton
The Snair article in CM
Studio Potter Dec. 1996 (some reference reduction)
Stoneware Glazes - Currie

Don Kopyscinski
Bear Hills Pottery
Newtown, CT

Who *really hates*........ to see the best crystals in the catch basins.

DonKopy@AOL.com

Christine Taylor on sat 8 nov 97

Nice reply that you gave.
I thought that you may be interested to know that I have (with my husbands
help-he is a physicist)taken photographs of the inside of the kiln while I
was doing a firing. They were taken with a ccd camera and then we put all the
photos together and have a short "video" from the time that the pot was bare
until it was covered with crystals.
I wrote about it in an article and hope to have it published in a book due
out I think next year.
I have been doing crystals for about 20 years now and have done hundreds of
tests and also tri-axial blends to get interesting color combinations of the
matrix and crystal. It is fun but the moment I have been paying more
attention to my other love-carriage driving (horse and carriage). I have
restored a 1915 vehicle and have just bought another one which may be 100
years old and I intend to restore that when the El Nino comes!!!!!
Christine Taylor from Los Angeles

Marc A. Baker on mon 16 feb 98

hi- i have been searching for a crystalline glaze receipe for
cone 8 or lower. i use an electric kiln for firing. does anyone
have a resource or a receipe that they would be willing to share?
i would be ever so greatful:>
thank you ahead of time.
marc

Rita Darling on thu 12 mar 98

Can someone tell the secret of how to maintain "a constant temperature" in
an electric kiln? I have three variable control switches. I've tried
watching the pyrometer and playing with switches, but have no luck. Am I
being too fussy about the temperature fluctuation? Also, what exactly is
meant by "soaking" because hereagain you are looking for a constant
temperature - an impossibility to me! TIA

Marcia Selsor on fri 13 mar 98

When I used to fired crystalline glazes in a Crusader kiln, the temp. was
maintained at a setting of 6 on the variable switches. But, to accent the
crystals fluctuating the temp. grows rings around the edges for some
interested effects. Just find the setting where they maintain
the temp by using a pyrometer and experiment.
Marcia in Montana

Rita Darling wrote:
>
> ----------------------------Original message----------------------------
> Can someone tell the secret of how to maintain "a constant temperature" in
> an electric kiln? I have three variable control switches. I've tried
> watching the pyrometer and playing with switches, but have no luck. Am I
> being too fussy about the temperature fluctuation? Also, what exactly is
> meant by "soaking" because hereagain you are looking for a constant
> temperature - an impossibility to me! TIA

Davesglaze on fri 13 mar 98

Too fussy, try to maintain a target zone temperature, ex. 1950-1850, with a
try for 1900 as a holding temerature ideal. If too hot turn one switch down ,
check every 10 minutes, if still the temp. is climbing turn down another
switch. Once the temp. stablizes check every 20 to 30 minutes. I have a skutt
self firing kiln, but used to use a even heat with pyometer to monetory the
temp. Also how you pack your kiln will affect temperature stability, ex. the
very top and very bottom usually don't give good results, but by packing the
middle (about 2/3 of the kiln) very tight you can maintain a more even temp.
Remember that nothing can touch each other in the glaze fireing. Do some
differnt tests with different glaze recipes for crystals , you will find that
different amounts of colorents and combinations of colorants will affect the
melt temperature and the hold results so use cones to tell where your cold
and hot spots are.You can find recipes to use in the top and bottom of your
kiln but it takes a whole lotta work. Good Luck Dave

Stephen Mills on sat 14 mar 98

This means sitting by the b****y thing with the setting on 4 or
thereabouts turning it on 'tll it hits temperature, turning it off, then
turning it on when it drops 2 - 5 degrees, then turning it on,
then........................................! then going out and buying
a simple thermocouple operated soak control, and using the time gained
to make more pots!
Steve
Bath
UK


In message , Rita Darling writes
>----------------------------Original message----------------------------
>Can someone tell the secret of how to maintain "a constant temperature" in
>an electric kiln? I have three variable control switches. I've tried
>watching the pyrometer and playing with switches, but have no luck. Am I
>being too fussy about the temperature fluctuation? Also, what exactly is
>meant by "soaking" because hereagain you are looking for a constant
>temperature - an impossibility to me! TIA
>

--
Steve Mills
Bath
UK
home e-mail: stevemills@mudslinger.demon.co.uk
work e-mail: stevemills@bathpotters.demon.co.uk
own website: http://www.mudslinger.demon.co.uk
BPS website: http://www.bathpotters.demon.co.uk

Roger Korn on sat 14 mar 98

Rita, darling,

(Couldn't resist) I've battled the same problem for a while and here's what
I do:

1. With an empty kiln, put in all but the top peep plugs and set up your
pyrometer.

2. Go through all the settings, letting the temp stabilize for 12 hours, or
until it moves less than, say, 20 degrees per hour. This is a major pain in
the butt, but you need to have this information, at least for the settings
around where you are getting the temp you want.

3. Record your settings and the top temp reached at each.

These will be the same temps reached for each setting as when the kiln is
loaded, but it will take longer to reach temp when the kiln is loaded.

When you are firing, you can get up to temp quickly by using higher
settings, but then switch to the proper setting for the desired temp when
the temp is within, say, 50 degrees.

For the soak-and-cool-slowly schedule of most crystalline glazes, turn the
setting down a notch at a time and let the kiln cool slowly. The time
depends on how heavily the kiln is loaded. When you reach a safe shut-off
temp, switch off the kiln and allow to cool per your normal routine.

Hope this helps. Let me know if anything's unclear.

Roger

Rita wrote:


Date: Thu, 12 Mar 1998 07:57:45 EST
From: Rita Darling
Subject: Crystalline Glazes
----------------------------Original message----------------------------
Can someone tell the secret of how to maintain "a constant temperature" in
an electric kiln? I have three variable control switches. I've tried
watching the pyrometer and playing with switches, but have no luck. Am I
being too fussy about the temperature fluctuation? Also, what exactly is
meant by "soaking" because hereagain you are looking for a constant
temperature - an impossibility to me! TIA

Ian Thompson on tue 21 apr 98

Hi there! I am studying ceramics in Brisbane, Australia and as part of
my glaze subject,I am researching barium zinc crystalline glazes. I am
finding it incredibly difficult to find any information. I have a basic
recipe and know about the red-blue reaction with nickel, but does
anybody have any more information they could send me? Anything such as
history or past uses or whatever, as well as any practical tips would be
a help.
Thanks for your time, Amanda Watson-Will
email: biffbang@bit.net.au

Samuel T DREW on mon 11 may 98

To clayart members,
I was wanting to get intouch with members who have used or know of
any crystalline glazes at 1100C/Cone 03 approximately. I'm not
talking about microcrystalline glazes, I'm looking for results like
you get with stoneware zinc crystalline glazes (willemite). I have a
general concept and realise one must provide a glasseus melt, fluid
enough for the crystalline to seed and form. A base glaze would be
gratefully received.

The mad professor from oz.

Marc Kiessling on tue 12 may 98

Hi Samuel:
Herbert H. Sanders book "Glazes for Special Effects", 1974 has a section
on Chromium Crystal Glaze Compositions (cone 014 to 010) and on Aventurine
Crystal Glaze Compositions (cone 06 to 4). I've not played around with
these, as yet, myself.
You will need a source of Lead (red -recommended, white, litharge, etc),
75% - 80% required, for the Chromium Crystal Glaze recipes he lists. (usual
"Red Flags" for Lead use apply)
He lists a number of frits (Hommel #25, #33, #71; Ferro #5301) for the
Aventurine Crystal Glaze recipes. I see you're from the "Land of Oz". Not
sure what you can aquire in frits downunder.
Hope this is of some use.
Best regards,
Marc (Victoria, B.C., Canada)

>----------------------------Original message----------------------------
>To clayart members,
>I was wanting to get intouch with members who have used or know of
>any crystalline glazes at 1100C/Cone 03 approximately. I'm not
>talking about microcrystalline glazes, I'm looking for results like
>you get with stoneware zinc crystalline glazes (willemite). I have a
>general concept and realise one must provide a glasseus melt, fluid
>enough for the crystalline to seed and form. A base glaze would be
>gratefully received.
>
>The mad professor from oz.
>
>

Ian Thompson on mon 6 jul 98

I'm just wondering if anyone out there knows anything about the history
of crystalline glazes? I believe there is a section on history in Diane
Creber's book, but it's sufficiently new that I can't find a copy here
(in Brisbane, Australia). TIA, Amanda Watson-Will
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

email: biffbang@bit.net.au

Brent Chalmers on mon 8 feb 99

Does anyone have any interesting matt crystalline glazes for cone 9-10
oxidation they are willing to share?

Tom Buck on sat 6 mar 99

Hello, Lori:
If you wish to study/use crystalline glazes you should be prepared
to do quite a bit of preparation, chief item of which is checking on the
literature. One article I see as valuable is a solidly technical one under
the byline of Bevan Norkin: "Crystalline Glazes: a precise method". It
appeared in USA's Ceramics Monthly March 1992 issue. Norkin cites a base
recipe and variations of it. Another article of interest appeared in UK's
Ceramic Review #128 (1991) in which Mimi Dann discussed her approach.
Two other articles may prove helpful. Peter Deck of Tasmania
recently reported on his research in Australian publication Ceramics
Technial issue #3 (1996). And in January 1975, Ceramics Monthly had a
brief article on the work of pioneer Hildegard Storr-Britz of Germany. Her
recipes may not travel well.
Norkin certainly argues for careful kiln control as being the
key essential.

Tom Buck ) tel: 905-389-2339
& snailmail: 373 East 43rd St. Hamilton ON L8T 3E1 Canada
(westend Lake Ontario, province of Ontario, Canada).

On Fri, 5 Mar 1999, Lori Locklear wrote:

> ----------------------------Original message----------------------------
> Hi
> Does anyone have any cone 6 or 9 reduction crystalline glazes recipes they
> could share with me.
> Lori

Fabienne Cassman on thu 3 jun 99

------------------
Hello,

I just finished digesting most of Diane Creber's handbook on Crystalline
Glazes. She focuses on cone 9 and above for this type of glaze. I was
wondering if any of you have experience with glazes around cone 6 using
electric kilns and what kind of crystals you get - shape, size etc. And,
is mid-range worth consideration, a lost cause or an area to explore as of =
yet?

=3EFrom what D.Creber writes, I can anticipate only the following problem:
cone 6 is not at least 400oF (222oC) above the crystal growth temperature
window, the minimum top temperature she suggests for macrocrystalline
glazes proper development.

Also, there seems to be a limited supply of information on crystalline
glazes. The following are mentioned in case someone else is on the look
out for this type of info:

F.H. Norton =5FThe Control of Crystalline Glazes=5F, ACerS 1937
David Snair =5FMaking and Firing Crystalline Glazes, CM 1975 (Vol23-10)

Anything else worth reading that is more recent perhaps?

TIA for your input, :)

=A4=BA=B0=60=B0=BA=A4=F8,=B8=B8,=F8=A4=BA=B0=60=B0=BA=A4=F8,=B8=B8,=F8=A4=BA=
=B0=60=B0=BA=A4=F8,=B8=B8,=F8=A4=BA=B0=60=B0=BA=A4=F8,=B8=B8,=F8=A4=BA=B0=60
Faye http://clay.justnet.com

Yes, I have learned from my mistakes...
I can reproduce them exactly.

Paul Lewing on fri 4 jun 99

Hi, Faye,
I've tested and even used several crystal glazes at cone 5. I didn't
fire them on the usual schedule, so got lots of small crystals instead
of a few big ones. But they were nice, although just as runny as their
highr fire counterparts. Here's one I used:

PL CRYSTAL
Frit 3110 38
Zinc Oxide 20
Silica 16
Titanium Dioxide 6.5
Mt St Helens Ash 16
Bentonite 1.5

If you don't have any MSH Ash, try wood ash. I think it's just in there
to give the crystals a "seed" to form around.
Paul Lewing, Seattle

Teresa Speakman on wed 2 feb 00

Does anyone have a good low firing crystalline glaze recipe, or suggestions
for a firing schedule to produce large crystals? By the way, I'm new on the
list, and this being my first experience with discussion lists, was
surprised, pleasantly, to find 80 e-mail messages last night! Any other
Ohioans out there?

Stephen Parry-Thomas on sun 6 feb 00

Hi,

A new UK site all about crystalline glazes is www.crystallineglazes.co.uk
the site is very new and under construction but worth a look.

Stephen + Karen Parry-Thomas,
www.morrigancraftpottery.co.uk

Joyce Lee on fri 11 aug 00

As I've mentioned several times, I'm intrigued by crystalline glazes...
the process and the product. Several of you have indicated that you too
are interested but, just as it is with me, the process seems too complex
just to BEGIN mixing glazes and following a firing schedule without
first learning more. The part that really gives me pause is hearing that
each pot in a crystalline firing needs a catcher-pot, which implies to
me that these glazes are predisposed to running. AND that (incredible)
each pot must then have the drip spots ground off!! EACH pot?? Have I
understood this correctly? There are others who would like to know,
also. For instance, if the catcher-pot is part of the process, does the
vase etc not stick to the catcher? I'm sure some of this terminology is
not what is normally used, but hope somebody who knows gets the idea.
Thank you.

Joyce
In the Mojave

Ann Brink on sat 12 aug 00

Joyce- a few years ago I experimented with crystal glazes, and didn't do any
grinding. I made a whole lot of covered boxes, enough to fill the kiln,
ranging in size from 4" in diameter to about 7" in diameter, 3-4" high.
The lids were flat on top and when trimming the lid, I left a slight ridge
near the outer edge, to confine any runny glaze. When glazing, I did the
flat area while the lid was on the wheel, using a brush- gave it a generous
coating. Then wax resist. Then dipped both parts of the box in some
regular glazes. Thus the top of the box was the decorative, framed part. I
tried variously colored versions of the same recipe. IT's true, you are
only trying the effect on a horizontal surface, but it's a start. Or how
about the interior of shallow bowls?

Good luck,
Ann Brink in CA--have you seen Faye Cassman's crystal-glazed bowls? Go to
the website below-
----- Original Message -----
From: Joyce Lee
To:
Sent: Friday, August 11, 2000 7:26 PM
Subject: crystalline glazes


> As I've mentioned several times, I'm intrigued by crystalline glazes...
> the process and the product. Several of you have indicated that you too
> are interested but, just as it is with me, the process seems too complex
> just to BEGIN mixing glazes and following a firing schedule without
> first learning more. The part that really gives me pause is hearing that
> each pot in a crystalline firing needs a catcher-pot, which implies to
> me that these glazes are predisposed to running. AND that (incredible)
> each pot must then have the drip spots ground off!! EACH pot?? Have I
> understood this correctly? There are others who would like to know,
> also. For instance, if the catcher-pot is part of the process, does the
> vase etc not stick to the catcher? I'm sure some of this terminology is
> not what is normally used, but hope somebody who knows gets the idea.
> Thank you.
>
> Joyce
> In the Mojave
>
>
____________________________________________________________________________
__
> 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.
>

Sharon31 on sat 12 aug 00

Hello Joyce!
First a small tour to: http://www.crystallineglazes.co.uk/
About how you make the bases to the pieces.

It is recommended to make them from the same claybody that your piece is.
This book, of Diane Creber , unfortunately in English, but I read it fast
and was easy to understand! I do handbuilding and also a bit barbarian, the
way I treat my crystalline, so I put under the pieces above the plate soft
bricks and after
the firing clean with a sharpening machine .I tried once, to put some pieces
one the same plate, and they stuck together.Another possibility, is if you
do
not glaze down to the bottom (outside) is to put sand at the saucer/plate
bellow your work I do
it sometime for plates or fruit dish. plates (can be good for tiles too). At
last, which
I tried, and got pretty nice, is to take a claybody which is beautiful the
way
it is, Can be Calico of Laguna, 140 of amaco, your claybody with black
grog, mid-fire tera cota and so on . You make in the center a circle with
white engob or better white porcelain, and glaze only on that part. No need
to put anything under the dish. Just remember to cover good enough to avoid
seeing the claybody through the glaze!
I have a big kiln (I think it is big) so it take some time to prepare works.
In general, you can put about half of pieces that in a regular firing.
...Do you know where is the real Mojave?



Ababi. South west of the Mojave sharon@shoval.org.il
http://www.israelceramics.org/main.asp?what=gallery
http://www.milkywayceramics.com/cgallery/asharon.htm
central part of Jordan kingdom at the (Bible time)
I know You know!

----- Original Message -----


From: Joyce Lee
To:
Sent: Saturday, August 12, 2000 05:26
Subject: crystalline glazes


> As I've mentioned several times, I'm intrigued by crystalline glazes...
> the process and the product. Several of you have indicated that you too
> are interested but, just as it is with me, the process seems too complex
> just to BEGIN mixing glazes and following a firing schedule without
> first learning more. The part that really gives me pause is hearing that
> each pot in a crystalline firing needs a catcher-pot, which implies to
> me that these glazes are predisposed to running. AND that (incredible)
> each pot must then have the drip spots ground off!! EACH pot?? Have I
> understood this correctly? There are others who would like to know,
> also. For instance, if the catcher-pot is part of the process, does the
> vase etc not stick to the catcher? I'm sure some of this terminology is
> not what is normally used, but hope somebody who knows gets the idea.
> Thank you.
>
> Joyce
> In the Mojave
>
>
____________________________________________________________________________
__
> 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.

Joyce Lee on sat 12 aug 00

Tom Buck and Dannon sent great posts about the crystalline glazes, for
which I am grateful. Their caveats helped me determine that this one is
going on hold until I'm less flibberty-jibbety about following my will
in clay. Since I had at least seven claybuds request information about
crystallines also, and since (except for Dannon once because I knew she
wouldn't mind and she was unavailable) I don't post other clayarters
posts without permission, I'm thinking that it would be great if they'd
both send theirs to the list, also. Very helpful. Whatta group. Thank
you, generous Dannon and Tom for taking your time. I'm going to be a
better and safer potter eventually because of you gurus.

Joyce
In the Mojave stunned this morning by the spectacle of the roadrunner
on the back of a lawnchair situated just on the other side of the
sliding glass doors..... he was facing me and looking the
desert-stuccoed walls over..
up&down&sideways ... finally saw what he wanted and jumped several feet
up to retrieve it... he did this several times.... don't even want to
speculate about what he was retrieving ....

Joyce Lee on sat 12 aug 00

Wow! I figured maybe a couple of you would have information and be
willing to share. Was I wrong! Amazing how many of you actually work
with such difficult glazes! I don't think I've ever even seen a real
life crystalline glazed pot! The websites are wonderful. And, yes,
Ababi, I do know where the original Mojave is, but I've never traveled
in that part of the world so have never stood on its sands. Thanks for
the reminder. Thank all of you for filling my file so when the day comes
that I'm mentally prepared, I'll be well aware of the joys and pitfalls
of trying to create lovely crystals on my lowly pots.

Joyce
In the Mojave with so many past or other or something lives experiences
that they sound too fictitious to bear telling ..... none in the recent
past ... and none more than wisps of memories or awarenesses flirting at
the outer edge of my consciousness.... just out of sight ... most
briefly perceived ....... some hovering in the mist of my cloudiest
brain cells for tantalizingly longer periods .....

De Ruyter jan on sat 12 aug 00

Joyce

You will find all answers on your question in the book of Peter Ilsley
" Macro-Crystalline glazes
published by The Crowood Press Ltd.
Ramsbury, Marlborough
Wiltshire SN8 2HR
England
Jan
----- Original Message -----
From: "Joyce Lee"
To:
Sent: Saturday, August 12, 2000 4:26 AM
Subject: crystalline glazes


> As I've mentioned several times, I'm intrigued by crystalline glazes...
> the process and the product. Several of you have indicated that you too
> are interested but, just as it is with me, the process seems too complex
> just to BEGIN mixing glazes and following a firing schedule without
> first learning more. The part that really gives me pause is hearing that
> each pot in a crystalline firing needs a catcher-pot, which implies to
> me that these glazes are predisposed to running. AND that (incredible)
> each pot must then have the drip spots ground off!! EACH pot?? Have I
> understood this correctly? There are others who would like to know,
> also. For instance, if the catcher-pot is part of the process, does the
> vase etc not stick to the catcher? I'm sure some of this terminology is
> not what is normally used, but hope somebody who knows gets the idea.
> Thank you.
>
> Joyce
> In the Mojave
>
>
____________________________________________________________________________
__
> 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.
>

Ingeborg Foco on sat 12 aug 00

I have never worked with crystalline glazes but have seen pots covered =
with crystals. Very intriguing and really different from other glazes.

About l5 years ago I was working on a large tile project and had many =
firing cycles to complete in order to obtain the 2000 + tiles required. =
Some of the tiles came out with interesting crystals - one here and =
another there. Some completely covered the tile and others had none. It =
certainly wasn't anything I was trying to do and I was not using a =
crystalline glaze to my knowledge. Using these tiles added an additional =
dimension to the finished product. I fire to ^10 Red and the glaze had =
rutile in it. My guess is that's what aided the crystal growth as well =
as the right cooling conditions.

All this talk about crystals makes me want to actively try to reproduce =
them. I've heard they are rather elusive and if I really want to grow =
them....they probably will not oblige me.

Ingeborg

Brad Sondahl on sun 13 aug 00

In answer to Joyce's query, catchment basins are not absolutely
necessary for crystalline glazes, but are rather like training wheels
for a bicycle: until you learn to ride them they help avoid the spills.
The glazes are necessarily runny, and I still have problems with
occasional runoffs and sticking to the kiln shelf, but use the glazes on
a production basis, and accept the occasional mess up as part of life.
My short guide to crystalline glazes on my webpages spells out the ways
to get crystals and avoid runoffs as well. Also I don't use any hold
times at certain temperatures, and have gotten good results with firing
to cone 10 in 6-7 hours. I think a consistent cone 10 oxidation
temperature is most critical and the lack of ability to attain it
produces most of the frustrating results.

--
Brad Sondahl
New Homepage: http://pages.about.com/bsondahl/index.html
New commercial pottery page http://sondahl.safeshopper.com
Original literature, music, pottery, and art

tgschs10 on sun 13 aug 00

Brad,
What a great webpage. I put it in my favorite file. And thanks for sharing
all that information. While I've been making pottery off and on for 20 years
[mostly off], I retired a little over a year ago and I am presently doing
quite a bit. I have both a gas and electric kiln and have been looking for
some nice oxidation glazes and certainly intend trying some of yours. If you
ever get down Orlando way, we are about 15 minutes from Disney, Universal
and Sea World and have a large home with a couple of spare rooms.
Tom Sawyer
tgschs10@msn.com

Gary Elfring on sun 13 aug 00

At 12:00 AM 8/13/00 -0400, you wrote:
>.... the process seems too complex
>just to BEGIN mixing glazes and following a firing schedule without
>first learning more. The part that really gives me pause is hearing that
>each pot in a crystalline firing needs a catcher-pot, which implies to
>me that these glazes are predisposed to running. AND that (incredible)
>each pot must then have the drip spots ground off!! EACH pot?? Have I
>understood this correctly? There are others who would like to know,
>also. For instance, if the catcher-pot is part of the process, does the
>vase etc not stick to the catcher? I'm sure some of this terminology is
>not what is normally used, but hope somebody who knows gets the idea.

I got interested in crystalline glazes a couple of years ago, bought the
books, and did a number of firings. (In a gas fired kiln, so I had to
also make sure I kept the kiln in oxidation.) Every firing I did worked
perfectly.

1) Mixing the glazes is no different than making any other glaze.

2) The actual firing is a bit longer than a normal one, and you have
to play with the temperature. If your kiln has some way of measuring
temperature (not cones!), this is fairly simple to do. If your kiln has
a digital controller, it's easy. I don't think it is possible to fire
crystalline glazes without a temperature probe.

3) You need to make TWO extra items for every pot. First, a flat bowl
catcher "plate" for drips. (These can be reused for several firings.)
Second, you need a ring or collar, the same width as the base of your pot,
that is 1 to 2 inches in height. You mix elmers glue and alimina (or ball
clay) to make a glue and use that to attach the ring/collar to the base
of your pot. Stand that on the catcher. Once fired, the glaze will run over
the ring/collar and might go down to the catcher bowl. The elmer's glue
burns away, leaving either powdered alumina or ball clay. You take a
coal chisel and just tap the joint between the pot and the ring/collar
(on the collar side). The thin glaze coat is all that holds the two
together, and it breaks away easily. You then do have to grind the base.
(Hint: stick some silicon carbide wet dry sand paper on your wheel, wet
it, and turn the wheel on to grind the base smooth in a few seconds.)


Elfring Fonts, Inc Bar Codes, MICR, and decorative fonts for Windows
http://www.elfring.com

David Hewitt on wed 25 oct 00

For anyone interested in crystalline glazes they might like to look at
the Dawnmist Studio Range on http://www.dawnmist.demon.co.uk/potdex.htm
This is an Exeter based company which supplies crystalline glazes and
also give much information on the application of such glazes and their
firing.
I have also added it to my 'Links' page together with Jurrassic Pottery
Studio (http://www.dinoclay.com/index.html) which has the Dictionary of
pottery terms in other languages.
Both worth adding to you Favourites.

--
David Hewitt
David Hewitt Pottery ,
7 Fairfield Road, Caerleon, Newport,
South Wales, NP18 3DQ, UK. Tel:- +44 (0) 1633 420647
FAX:- +44 (0) 870 1617274
Web site http://www.dhpot.demon.co.uk

william schran on fri 5 jan 01

Cheryl - I'd be happy to share whatever information I have. I've been
working in crystalline glazes at cone 6 for a while and wrote an
article for ClayTimes last Sept./Oct. issue. Please feel free to
email me off line.
Bill Schran

Cantello Studios on sun 7 jan 01

Hi bill I to am interested in trying to grow crystals at cone 6. I have been
working at cone 10 for a long time and have had some good crystalline growth
but my kiln and my power are not in sink. The problem hears is my kiln takes
about 85 amps. And all I have coming into the studio is 100 amps. And the
kiln is some 140ft. from the power source. I have the old power drain thing
going on but if I could work at cone 6 I may be able to pull this off. If
you would be willing to share some glaze base starting points I would be
very grateful. You could e-mail me off list at tleecan@2xtreme.net I thank
you in advance. Chris soon to be at www.CantelloStudios.com my web site will
be up by the end of the month if not sooner.

-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of william schran
Sent: Friday, January 05, 2001 2:08 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: crystalline glazes

Cheryl - I'd be happy to share whatever information I have. I've been
working in crystalline glazes at cone 6 for a while and wrote an
article for ClayTimes last Sept./Oct. issue. Please feel free to
email me off line.
Bill Schran

____________________________________________________________________________
__
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.

Chomsky501@AOL.COM on sun 7 jan 01

Cheryl wrote....
"I am looking for potters that work with crystaline glazes. Can anyone get
me in touch with anyone who works in this filed?
Thank you"
Cheryl Hanley

.....Cheryl, I got started on macro-crystalline glazes this past summer. I've
had good results from Isley's recipes, and also one of the cone 6 recipes in
Clay Times, a few months back. But I'm basically just starting out...tested
about 14 or 15 glazes so far. (I'll try to attach a picture...)

I'd love to share info, glazes, firing schedules, etc with you and any and
all others who are doing this. Should I contact you direct? Are you
building a list of interested potters?

I am at Florida Atlantic University, just starting into the spring
semester...I will be focussed on shino's - 80 recipes and 4 clays to test,
for openers - but expect to do some crystallines too. In the summers, I have
a (just completed) studio partly in Toronto, and partly at my cottage,"up
north" I'd love to hear from you, and would be glad to send recipes, firing
schedules, etc.

Garry Dick
E-Mail chomsky501@aol.com



____________________________________________________________________

Edouard Bastarache on mon 26 feb 01

Hello all,


Smart and I are wondering why crystalline glazes seem
to be applied only on porcelain or white burning bodies.
We have been exchanging our theories back and forth on the
Net for a few days without success.

Anybody would help?

Later,




Edouard Bastarache
Irr=E9ductible Qu=E9becois
Sorel-Tracy
Dans / In "La Belle Province"
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/

Dennis Mummert on tue 27 feb 01

Edouard;

I hope I don't sound like a philistine, but Amaco sells a crystalline glaze
which does well over either a low-fire white body or terra-cotta. The
effects on terra-cotta are rather striking. The glaze is Amaco LT-30,
Tobacco Brown. It doesn't run much, in fact behaves like most ordinary
commercial glazes. The surface is semi-gloss, and the crystals tend to be
small.

Dennis Mummert
Earthen Fire Studios
Fairborn, Ohio, USA


-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of Edouard Bastarache
Sent: Monday, February 26, 2001 11:34 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Crystalline glazes


Hello all,


Smart and I are wondering why crystalline glazes seem
to be applied only on porcelain or white burning bodies.
We have been exchanging our theories back and forth on the
Net for a few days without success.

william schran on tue 27 feb 01

Edouard - Crystalline glazes are used on porcelain for the white
background (crystalline glazes are transparent, white clay showing
cleaner color) and for the smooth surface (the glazes run and any
little bit of grog might create a streak in the glaze flo).
Bill

Ababi on tue 27 feb 01

You can glaze on buff claybody, but as the very low alumina gloss almost
clear crystalline glaze, if it is a blue glaze, will be green. If the clay
will be motled so will be the glaze. The advantage of the porcelain is the
high kaolin. Now I am writing something that I understand, but not enough:
The glaze has very low alumina, the high alumina body, covers the shortage
of alumina in the glaze. Anyway I made some success with none porcelain rich
kaolin body.
In my next reincarnation I will not runaway from chemestry lessons
Ababi Sharon
ababisha@shoval.ardom.co.il
http://members4.clubphoto.com/ababi306910/

Jean Silverman on tue 27 feb 01

Hi all,
Well, I've tried crystals on white stoneware--specifically, I took my
crystalline glaze which forms nice crystals on porcelain, which I had
already been using successfully, and tried to run some color tests on some
Miller's #510 white stoneware (which is also grogged). Results: muddy color
(nothing's as white as porcelain) no crystals, just a rough messy surface.
I wondered if the grogged surface interfered with glaze flow and therefore
crystal formation. I'm talking about macrocrystalline glazes here of
course; microcrystallines of many types seem to work fine over anything if
the right thickness--color changes over different clay bodies, naturally.

>Smart and I are wondering why crystalline glazes seem
>to be applied only on porcelain or white burning bodies.
>Edouard Bastarache

Jean Silverman
Plum Tree Pottery
41 Neal Mill Rd.
Newmarket NH 03857
603-659-2632

Fabienne Micheline Cassman on tue 27 feb 01

At 11:33 PM 02/26/2001 -0500, you wrote:
>Hello all,
>
>Smart and I are wondering why crystalline glazes seem
>to be applied only on porcelain or white burning bodies.
>We have been exchanging our theories back and forth on the
>Net for a few days without success.
>
>Anybody would help?

Bonjour Edouard :)

Let me take a stab at this one. I am still working on figuring out these
macro-crystalline buggers, but this is what I observed. Perhaps someone
more in tune with them can expand on it.

White bodies are recommended because of their being more responsive and
"true" to the color you are trying to achieve. I use a c/6 porcelaneous
body which is somewhat yellowish compared to the c/10 winter white buttery
porcelains, as I call them. The same crystalline glaze that yields a
yellow background with blue crystals on the c/10, gives me an muted
greenish yellow with blue gray crystals on the yellowish c/6 porcelain. In
a sense it's great; it expands our palette by just changing the "canvas." :)

This seems to indicate that there is an exchange occurring between the
glaze and the body. Fast firing seems to avoid that exchange takes place
at length; the alumina contained in the body is a crystal inhibitor once in
the glaze. On the same token, iron contained in the body may be
contaminating the glaze enough to alter its color and perhaps the size of
the crystal. I've noticed that iron is not a preferred colorant these glazes.

Cheers,

Fabienne
--
Milky Way Ceramics http://www.milkywayceramics.com/

Yes, I have learned from my mistakes...
I can reproduce them exactly.

Gavin Stairs on tue 27 feb 01

At 11:33 PM 2/26/01, Edouard Bastarache wrote:
>Smart and I are wondering why crystalline glazes seem
>to be applied only on porcelain or white burning bodies.
>We have been exchanging our theories back and forth on the
>Net for a few days without success.

Dear Edouard,

While the ultimate reason must be esthetic, I have a few ideas about why
this would be so.

Macro-crystalline glazes are runny, which means that they start out as
fully fluxed glasses, for the most part. All such glasses are transparent,
rather than translucent, meaning that any imperfections in the ground
behind the glaze are visible through the glaze. In a crystalline glaze,
the usual objective is to feature the macro-crystals, and any other details
might detract from this effect. So a white, uniform ground would seem to
be a good starting point. Note that some crystalline glazes are very dark
(e.g., tenmoku), and the ground is of less concern in these cases.

Second, stoneware bodies often have specks and crystals which may interact
with the glaze, either discolouring it, or acting as initiation centres for
crystal formation. In the former case, the resulting colouring may not be
desirable. In the latter case, there may be so many nucleation centres
that too many crystals start, resulting in less of the macro-crystal effect.

All of these effects may on occasion be desirable, so I would guess that
occasional experimentation with stoneware bodies might be profitable.

Gavin



Gavin Stairs
Stairs Small Systems
921 College St., # 1-A
Toronto, Ontario, Canada M6H 1A1
phone: (416)530-0419 stairs@stairs.on.ca

Jeff Lawrence on fri 9 mar 01

Edouard Bastarache was wondering why porcelain was preferred under
crystalline glazes...

Hello Edouard,

Everyone mentions smoothness and I have to agree smoothness is good -- my
crystalline glazes come out smoother on grog- and sand-free clay.

But crystals form fine on other clays in the same firings, including B-mix
and a white stoneware with sand in it. The stoneware with sand in it, has
unpleasant graininess on edges where the glaze is thin.

There's another characteristic I notice which I'd enjoy hearing others'
thoughts on. I think of it alternatively as density and resistance to
caustic glaze.

The same glaze that behaves well on porcelain or smooth white stoneware will
etch itself up to a millimeter deep into a more open body. I was also
thinking that the graininess mentioned above may be made worse by the glaze
eating away at the clay, but not being able to eat into the silica sand.
Porcelain recipes have less clay and less fine-grain material than other
types; does this mean they resist the melting action of the glaze better? My
only other guess is that a vitrified clay, be it porcelain or other,
presents a smoother surface that the glaze cannot eat into as readily.

Hmmm ...

Jeff Lawrence vox: 505 753 5913
Sun Dagger Design fax: 505 753 8074
18496 US HWY 84/285 jml@sundagger.com
Espanola NM 87532 www.sundagger.com

Scott B. Ackerman on tue 21 aug 01

Here is a questions for all of you "glaze experts". I have found many
"base" formulas for crystalline glazes (such as ferro frit 3110-50,
silica-25, zinc oxide-25) and have noticed that they all suggest firing
up to cone 8-9 and then doing a 200c cool and soak for 4-6 hours.
According to my limited knowledge of glaze formulas this base glaze
would probably melt at cone 2-4, so why take it to cone 8-9? Does it
have to reach a certain state of fluidity before cooling, or am I just
missing something here. I am interested in developing a cone 5-6
crystalline glaze because that is where I fire all of my other glazes.
And yes I understand that most of the information about crystalline
glazes is nothing more than an informed jumping off point, and that I
will have to do a lot of testing just to probably see one "eensy-weensy"
crystal form. Thanks.

Scott B. Ackerman
Synergy Graphics, LLC
2290 E. Prospect Rd.
Suite 2
Fort Collins, CO 80525
(970)407-8480

John Hesselberth on tue 21 aug 01

on 8/21/01 9:44 AM, Scott B. Ackerman at scott@SYNGRAPHICS.COM wrote:

> According to my limited knowledge of glaze formulas this base glaze
> would probably melt at cone 2-4, so why take it to cone 8-9? Does it
> have to reach a certain state of fluidity before cooling, or am I just
> missing something here.

Hi Scott,

You are not missing anything. Growth of large crystals--so-called
macrocrystalline glazes--requires fluidity or mobility within the liquid
matrix so molecules can move into position for crystal formation. It also
requires time for the crystals to grow. Hence the long soak or hold times.
A tiny bit of particulate matter is often used to seed the crystals. You
will notice that all macrocrystalline glaze recipes are extremely low in
alumina to help the fluidity. They also often contain a significant amount
of zinc because zinc silicate forms nice crystals.

As to why you can't just bring them up to the soak temperature and hold them
there, I have to speculate a bit. I would guess it is because you have to
get everything very thoroughly melted first, i.e. you have to get whatever
lattice structure or matrix or smaller crystals that existed prior to firing
completely broken down.

An excellent book on the subject is one written by Peter Ilsley titled
Macrocrystalline Glazes: The Challenge of Crystals. It was just published in
1999 so it should still be available at The Potters Shop or elsewhere.

Regards,

John

Web site: http://www.frogpondpottery.com Email: john@frogpondpottery.com

"The life so short, the craft so long to learn." Chaucer's translation of
Hippocrates, 5th cent. B.C.

Fabienne Micheline Cassman on tue 21 aug 01

At 07:44 AM 08/21/2001 -0600, you wrote:
>According to my limited knowledge of glaze formulas this base glaze
>would probably melt at cone 2-4, so why take it to cone 8-9? Does it
>have to reach a certain state of fluidity before cooling, or am I just
>missing something here. I am interested in developing a cone 5-6

Hello :)

You are not missing a thing at all. I'm far from being a guru, but
crystalline, specifically zinc-silicate glazes, are my favorites for the
time being. I have worked with them at cone 6, 8, and 9 with success, but
I distinctly prefer some of the glazes I have at cone 9 and 8 -- Maybe I'll
put more elbow grease into them later at cone 6 to replicate them.

Indeed, these glazes have to reach a good amount of fluidity; however,
overdoing it would obliterate the seeds for the crystals and give a high
gloss and underdoing it would only yield nasty rough surfaces or a surface
completely covered with crystals. You'll have to find the top temperature
and range that works well for the capability of your kiln in relation to
the glaze you are experimenting with. You are right to say that the
literature will only be able to provide you with ballpark figures.

The range of growth is listed as low as 1000oC and as high as
1150oC. Where in that range will dictate the shape of the crystal you will
have. Personally, I prefer staying away from the edges of the
range. Also, the time length of the soak will dictate how large the
crystal will be. But again, finding what the glaze and your kiln can do
together is the key.

For available literature and other information, check my web site at
http://www.milkywayceramics.com/mf/glazes.htm, see the "Crystals Simply
Put" heading which should answer your question.

I hope this helps. Good luck with them; they have a life of their own :)

Fabienne
--
Milky Way Ceramics http://www.milkywayceramics.com/

Yes, I have learned from my mistakes...
I can reproduce them exactly.

Marcia Selsor on tue 21 aug 01

Yes, it has to be very fluid to form the crystals. It is actually quite
overfired for the base maturity point. I did my thesis on Crystalline
glazes back in 1972. They are very interesting. Best research material I
found was in the library of the dept. of ceramics engineering at UI
Champaign Urbana from 1903 or so.
Marcia in Montana

"Scott B. Ackerman" wrote:
>
> Here is a questions for all of you "glaze experts". I have found many
> "base" formulas for crystalline glazes (such as ferro frit 3110-50,
> silica-25, zinc oxide-25) and have noticed that they all suggest firing
> up to cone 8-9 and then doing a 200c cool and soak for 4-6 hours.
> According to my limited knowledge of glaze formulas this base glaze
> would probably melt at cone 2-4, so why take it to cone 8-9? Does it
> have to reach a certain state of fluidity before cooling, or am I just
> missing something here. I am interested in developing a cone 5-6
> crystalline glaze because that is where I fire all of my other glazes.
> And yes I understand that most of the information about crystalline
> glazes is nothing more than an informed jumping off point, and that I
> will have to do a lot of testing just to probably see one "eensy-weensy"
> crystal form. Thanks.
>
> Scott B. Ackerman
> Synergy Graphics, LLC
> 2290 E. Prospect Rd.
> Suite 2
> Fort Collins, CO 80525
> (970)407-8480
>
> ______________________________________________________________________________
> 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.

--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
http://www.imt.net/~mjbmls/May2001.html
http://www.imt.net/~mjbmls/Tuscany2001.html
http://www.imt.net/~mjbmls/Gallery.html

Ababi on wed 22 aug 01

Yes I realized that the crystalline glazes has similar bases for ^9 and ^6
^5 . I did it in ^6 it was an interesting experience, yet if you want to be
an expert, you need a life time for it.
The recipes are easy to make the apply thick. The soaking times are the big
story.
Use ^6 porcelain.
Read Crystalline Glazes by Diane Creber is a basic book
I answered you though I am only a glaze addict.
Ababi Sharon
ababisharon@hotmail.com
http://members4.clubphoto.com/ababi306910/
http://www.milkywayceramics.com/cgallery/asharon.htm
http://www.israelceramics.org/

----- Original Message -----
From: "Scott B. Ackerman"
To:
Sent: Tuesday, August 21, 2001 03:44
Subject: Crystalline glazes


> Here is a questions for all of you "glaze experts". I have found many
> "base" formulas for crystalline glazes (such as ferro frit 3110-50,
> silica-25, zinc oxide-25) and have noticed that they all suggest firing
> up to cone 8-9 and then doing a 200c cool and soak for 4-6 hours.
> According to my limited knowledge of glaze formulas this base glaze
> would probably melt at cone 2-4, so why take it to cone 8-9? Does it
> have to reach a certain state of fluidity before cooling, or am I just
> missing something here. I am interested in developing a cone 5-6
> crystalline glaze because that is where I fire all of my other glazes.
> And yes I understand that most of the information about crystalline
> glazes is nothing more than an informed jumping off point, and that I
> will have to do a lot of testing just to probably see one "eensy-weensy"
> crystal form. Thanks.
>
> Scott B. Ackerman
> Synergy Graphics, LLC
> 2290 E. Prospect Rd.
> Suite 2
> Fort Collins, CO 80525
> (970)407-8480
>
>
____________________________________________________________________________
__
> 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.
>

william schran on wed 22 aug 01

Scott - Yes, the glaze has to be fluid enough to flow from the pot.
Many of the cone 9/10 glazes will work at cone 6 (often have to help
with adding more flux such as lithium carb.). Wrote an article in
last Sept/Oct issue of "ClayTimes" on cone 6 crystalline glazes.
Bill

>Here is a questions for all of you "glaze experts". I have found many
>"base" formulas for crystalline glazes (such as ferro frit 3110-50,
>silica-25, zinc oxide-25) and have noticed that they all suggest firing
>up to cone 8-9 and then doing a 200c cool and soak for 4-6 hours.
>According to my limited knowledge of glaze formulas this base glaze
>would probably melt at cone 2-4, so why take it to cone 8-9? Does it
>have to reach a certain state of fluidity before cooling, or am I just
>missing something here. I am interested in developing a cone 5-6
>crystalline glaze because that is where I fire all of my other glazes.
>And yes I understand that most of the information about crystalline
>glazes is nothing more than an informed jumping off point, and that I
>will have to do a lot of testing just to probably see one "eensy-weensy"
>crystal form. Thanks.
>
>Scott B. Ackerman
>Synergy Graphics, LLC
>2290 E. Prospect Rd.
>Suite 2
>Fort Collins, CO 80525
>(970)407-8480
>
>______________________________________________________________________________
>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.

Kenneth J. Nowicki on tue 13 nov 01

Hi Clark...

Mel posted your message on Clayart today and I am responding to it for you. I
don't know if you are in Southern California or not, but judging by Mel's
initial response to you I am assuming you are. I am in the San Fernando
Valley and I have a guy's name to pass along to you if you are interested.

Xavier Gonzalez
5407 Willis Avenue
Sherman Oaks, CA 91411
818-779-0990

I first met Xavier at the Pasadena Art Show about a year or more ago. His
exquisite crystalline pottery caught my eye. That is his specialty and he
does very beautiful work. I bought two small vases from him and slyly hid
them from my wife who was with me that day at the art show (one of the pieces
was one she really wanted and I scoffed and told her we couldn't afford it).
I later snuck back and bought it and talked to Xavier for a while. Nice guy.
I believe he teaches High School ceramics as well as doing his own art.
Anyway... the information is off his card... I hope it's still current. You
might try giving him a call... he may be able to meet your needs. Good luck!

Funny thing, on the way back out as we were leaving we went by his booth
again... my wife looked for the vase she had spied earlier and of course it
was gone. She asked Xavier about it and he told her some guy came by right
after you were here and bought it (giving me a wink and a nod over her
shoulder)... I just grinned. She was sooo mad at me for not letting her buy
it. Boy was she surprised Christmas morning when she opened that little box
under the tree! Heh heh... now THAT was fun!

Best wishes...

Ken
in Encino, CA (soon to be Port Washington, NY)

We opened escrow on the sale of our home yesterday after getting a decent
offer over last weekend. Hooray! I feel like a weight has been lifted off my
back. Now it's time to get busy and begin packing!
..............................................................................

.....................
In a message dated 11/13/01 3:39:13 AM Pacific Standard Time,
melpots@PCLINK.COM writes:

> Subj: Fwd: RE: Crystalline Glazes
> Date: 11/13/01 3:39:13 AM Pacific Standard Time
> From: melpots@PCLINK.COM (mel jacobson)
> Sender: CLAYART@LSV.CERAMICS.ORG (Ceramic Arts Discussion List)
> Reply-to: CLAYART@LSV.CERAMICS.ORG (Ceramic Arts Discussion List)
> To: CLAYART@LSV.CERAMICS.ORG
>
> anyone help this person.
> looking for a potter in california, or elsewhere to make some
> pots for him.
> mel
> post him, not the list.
>
>
> >From: "Clark Collins"
> >To: "'mel jacobson'"
> >Subject: RE: Crystalline Glazes
> >Date: Mon, 12 Nov 2001 21:48:28 -0800
> >X-Mailer: Microsoft Outlook, Build 10.0.2616
> >Importance: Normal
> >
> >Any suggestions on just a good potter that would be willing to make some
> >crystalline vases for me...?
> >
> >Any help is appreciated!
> >
> >Thank you!
> >
> >Clark Collins
> >
> >-----Original Message-----
> >From: mel jacobson [mailto:melpots@pclink.com]
> >Sent: Monday, November 12, 2001 9:02 PM
> >To: Clark Collins
> >Subject: Re: Crystalline Glazes
> >
> >At 07:33 PM 11/12/20
> >i just don't have contacts in southern california that i could suggest.
> >sorry.
> >mel
>
> From:
> Minnetonka, Minnesota, U.S.A.
> web site: http://www.pclink.com/melpots

Dannon Rhudy on wed 20 mar 02

I'm looking to add a book or two on crystalline
glazes to our library. The only two I've come
across are "Crystalline Glazes" by Diane Creber,
and "Macro-crystalline Glazes" by Peter Isley.

Does anyone have a recommendation between the two,
or additional books that are available?

Thanks for any help.

regards

Dannon Rhudy

Jeff Lawrence on wed 20 mar 02

Dannon was asking about crystalline glaze books

Hi Dannon,

I have both the Ilsley and the Creber books. The Creber
book is a good introduction with some fine color plates
and solid information -- certainly worth a $20 bill.

The Ilsley book costs more but its larger format (9"X12")
means bigger pictures - very important to appreciate the
detail. The photography is generally quite good, and many
of the photos have a sidebar that lists both recipe
and percentages of colorant used on the piece shown
- a lot of work by the author that answers the very first
question I have about the pot! The overview of featured
artists includes short articles by each detailing their
recipes, firing regimens and personal aesthetic along
with photos of their work. I find this book exhilirating.

Best,
Jeff

Jeff Lawrence
jml@cybermesa.com

william schran on thu 21 mar 02

Dannon - On "digitalfire.com" there's a new book on crystalline
glazes by Fara Shimbo. I'ts available as a download, CD, or in book
form. I have the two books you mentioned, had worked from Herbert
Sander's "Glazes for Special Effects" since it came out in the 70's ,
just added Fara's ebook (got the CD) and she also has a online
discussion site available to all who get one form of her book. I just
got finished doing a crystalline firing to cone 6 with some formulas
from her book. Send me a message later and I'll let you know how it
went.
Bill

James Bowen on thu 21 mar 02

Try to find a copy of the out of print book "Glazes for
Special Effects" by Herbert Sanders. It has an excellent
section on crystalline glazes along with sections on the
other popular Copper, Luster, Ash, and Raku glazes.



Stay Centered
James Bowen
Boyero CO
jbowen43@yahoo.com
jbowen43@plains.net


" I prefer a man who will burn the flag and then wrap
himself in the Constitution to a man who will burn the
Constitution and then wrap himself in the flag."

Ian Macmillan on thu 21 mar 02

Diane's book is excellent. Of course, she is Canadian, so I may be
prejudiced. I have also seen her work in her studio.

Ian



>I'm looking to add a book or two on crystalline
>glazes to our library. The only two I've come
>across are "Crystalline Glazes" by Diane Creber,
>and "Macro-crystalline Glazes" by Peter Isley.
>
>Does anyone have a recommendation between the two,
>or additional books that are available?
>
>Thanks for any help.
>
>regards
>
>Dannon Rhudy
>
>______________________________________________________________________________
>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.

Marianne Lombardo on thu 17 oct 02

Someone here was recently asking about cone 6 Crystalline glazes, I believe.

This web site seems to contain a wealth of information on Crystalline glazes
at various temperatures:

http://crystalline-ceramics.info/index.html

Marianne Lombardo
Omemee, Ontario, Canada
email: mlombardo@nexicom.net

Catherine White on fri 18 oct 02

Marianne,
I'd had no interest in crystalline glazes thinking they were more a
low-fire process. The web site indicates they can occur at high temps.......
^10. I'll look into this, though I have more than enough on my plate trying
to do all my present projects.
Thanks from,
Catherine in Yuma, AZ


----- Original Message -----
From: "Marianne Lombardo"
To:
Sent: Thursday, October 17, 2002 6:31 PM
Subject: Crystalline Glazes


> Someone here was recently asking about cone 6 Crystalline glazes, I
believe.
>
> This web site seems to contain a wealth of information on Crystalline
glazes
> at various temperatures:
>
> http://crystalline-ceramics.info/index.html
>
> Marianne Lombardo
> Omemee, Ontario, Canada
> email: mlombardo@nexicom.net
>
>
____________________________________________________________________________
__
> 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.

Ellie Blair on thu 3 apr 03

I need to know the best way to finish off the bottoms of crystalline =
pots. There are instances when the bottom needs to be ground even.
Ellie Blair
Lawrence, Kansas

william schran on thu 3 apr 03

Ellie Blair wrote:
>>crystalline pots. There are instances when the bottom needs to be
>ground even.>

I use three different grinders. One is a silicon carbide wheel on a
bench grinder to get the big stuff. I then use a silicon carbide disc
that has a self adhesive back that I attached to a plastic bat and
use that on my wheel to grind and even out the bottom. I then have a
diamond impregnated disc, again self adhesive on back, attached to a
bat and used to get a smooth bottom.
Bill

>
>
>
>______________________________________________________________________________
>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.