Deborah Bouchette on wed 31 mar 99
------------------
The Ceramics Web GLAZEBASE at http://art.sdsu.edu/ceramicsweb/index.html has=
the
following recipe you might be interested in trying...(I entered cone =
=3Ccontains=3E
10 and surface =3Ccontains=3E =22crystal=22 as the search criteria)
Glaze Name: Emmanuel Cooper's Blue Crystal =23383
cone: 10
color: slate blue w/crystals
surface:gloss w/ crystalline
firing:Untested
date: 6/24/97
recipe:
36.84 G-200 Feldspar, (or Custer)
10.53 Whiting
21.05 dolomite
31.58 flint
100.00 =25 Totals:
Also add:
10.53 Rutile
5.26 bentonite
1.58 Cobalt Carbonate
comments:
From the ClayArt Glaze Recipe Database at SDSU.
If you test this glaze and find it useful
please consider resubmitting it to the GlazeBase database.
estimated thermal expansion: 73.78x10-7/=B0C
Unity Formula for Emmanuel Cooper's Blue Crystal =23383:
0.100 K2O 0.173 Al2O3 2.335 SiO2
0.050 Na2O 13.5:1 Si:Al Ratio
0.578 CaO
0.273 MgO
Percentage Analysis for Emmanuel Cooper's Blue Crystal =23383:
65.59 =25 SiO2
8.25 =25 Al2O3
4.41 =25 K2O
1.45 =25 Na2O
15.16 =25 CaO
5.15 =25 MgO
Possible Health Hazards: Flint: free silica-wear a NIOSH approved dust =
mask
when handling
dry material
You better have some wine yerself befor you try this one=21 Quite =
variable.
At its best a beautiful
slate blue with small crystals (1/16) peppering the surface (green =
centers
w/ white halo).
slightly fluid. Narrow firing range, just Knock down =5E10 and leave it=
at
that, soak it slightly
cooler. I usually soak between 2050-2150 F ( I think my pyrometer is a
little low). Soak time is
important. Longer soak and the crystals completely cover the surface. I
found a 1/2 hr soak
was about right. beautiful no matter how you fire it. I've sold a lot =
of
this. I use Dave's porcelain
from Laguna. Dean McRaine =3Cbeezer=40aloha.net=3E on the north shore =
of Kauai
---------------------
Deborah A. Bouchette
principal=40aleatoric-art.com
+1.503.690.2448 phone/fax
-----Original Message-----
From: Gary Elfring =5BSMTP:ge=40elfring.com=5D
Sent: Tuesday, March 30, 1999 4:48 AM
Subject: Zinc crystal glaze help??
----------------------------Original message----------------------------
I have been lurking on this list for some time,
but have never responded or asked a question. I
have been taking ceramics classes at our local
community college for 3 years now.
Several of us in class would like to try our hand
at making a zinc crystal glaze and growing those
beautiful crystals. I have bought several pieces
in blue and green that used this type of glaze.
However, no one at the college has ever done this,
so we are on our own. We have all the equipment and
chemicals we could want, but need a glaze recipe
and some ideas on how to do the firing and cooling.
We typically fire things here in a gas kiln to cone
10 (reduction), but we have numerous kilns and can
also do electric, and to any cone.
Is there any source of information and/or glaze
formulas available for doing this? Any help would
be greatly appreciated.
Elfring Soft Fonts, Inc. http://www.elfring.com
http://www.barcodingfonts.com http://www.micrfonts.com
Bar Codes, MICR, Signatures, plus popular TrueType fonts and clip art.
Marcia Selsor on fri 2 apr 99
------------------
Dear Gary,
Crystalline glazes were the topic of my thesis in grad school in 1972.
I did a lot of reading in the Ceramics Engineering archives (1903 era) in
Champaign/Urbana even though I was a grad at SIU Carbondale.
The first time I fired a batch of these glazes, one fell over in my =
personal
brand new kiln and ate a hole in the floor about 4=22 wide. They are very
caustic.The best way I have found and how it was done in the early years of
the century is as follows:
bisque to =5E10 (this avoids shrinkage in the glaze firing)
use gum in the glaze and spray onto surface (wear a mask)
place on a completed-kilnwashed-surface of brick cut to fit the base =
perfectly
put pot and brick in a waster bowl to catch the runoff.
After the firing, chisel the brick from the pot and grind (wear eye goggles
and a mask)
My favorite colorant was nickel which produces a teal blue crystal (1.5=22 =
in
diameter) on an amber background-stunning glaze
=2A=2A It is really important to let the glaze run and then quickly drop the
temperature to a few hundred degrees below =5E10. Soaking grows the crystals=
and
the soaking temperature determines the shape of the crystal much like frost =
on
a glass window. Raising and lowering the temp.puts a ring aroung the =
crystal.
HOWEVER considering the damage that these glazes can cause, use every
precaution to protect the kiln equipment
if it is not yours personally. Make sure all soft brick has kiln wash
-floor and the bisket for the pot.
Deborah Bouchette wrote:
=3E
=3E ----------------------------Original message----------------------------
=3E ------------------
=3E The Ceramics Web GLAZEBASE at http://art.sdsu.edu/ceramicsweb/index.html=
has
the
=3E following recipe you might be interested in trying...(I entered cone
=3Ccontains=3E
=3E 10 and surface =3Ccontains=3E =22crystal=22 as the search criteria)
=3E
=3E Glaze Name: Emmanuel Cooper's Blue Crystal =23383
=3E
=3E cone: 10
=3E color: slate blue w/crystals
=3E surface:gloss w/ crystalline
=3E firing:Untested
=3E date: 6/24/97
=3E recipe:
=3E
=3E 36.84 G-200 Feldspar, (or Custer)
=3E 10.53 Whiting
=3E 21.05 dolomite
=3E 31.58 flint
=3E 100.00 =25 Totals:
=3E
=3E Also add:
=3E 10.53 Rutile
=3E 5.26 bentonite
=3E 1.58 Cobalt Carbonate
=3E
=3E comments:
=3E From the ClayArt Glaze Recipe Database at SDSU.
=3E If you test this glaze and find it useful
=3E please consider resubmitting it to the GlazeBase database.
=3E
=3E estimated thermal expansion: 73.78x10-7/=B0C
=3E
=3E Unity Formula for Emmanuel Cooper's Blue Crystal =23383:
=3E 0.100 K2O 0.173 Al2O3 2.335 SiO2
=3E 0.050 Na2O 13.5:1 Si:Al Ratio
=3E 0.578 CaO
=3E 0.273 MgO
=3E
=3E Percentage Analysis for Emmanuel Cooper's Blue Crystal =23383:
=3E 65.59 =25 SiO2
=3E 8.25 =25 Al2O3
=3E 4.41 =25 K2O
=3E 1.45 =25 Na2O
=3E 15.16 =25 CaO
=3E 5.15 =25 MgO
=3E
=3E Possible Health Hazards: Flint: free silica-wear a NIOSH approved =
dust
mask
=3E when handling
=3E dry material
=3E You better have some wine yerself befor you try this one=21 Quite =
variable.
=3E At its best a beautiful
=3E slate blue with small crystals (1/16) peppering the surface (green
centers
=3E w/ white halo).
=3E slightly fluid. Narrow firing range, just Knock down =5E10 and =
leave it at
=3E that, soak it slightly
=3E cooler. I usually soak between 2050-2150 F ( I think my pyrometer =
is a
=3E little low). Soak time is
=3E important. Longer soak and the crystals completely cover the =
surface. I
=3E found a 1/2 hr soak
=3E was about right. beautiful no matter how you fire it. I've sold a =
lot of
=3E this. I use Dave's porcelain
=3E from Laguna. Dean McRaine =3Cbeezer=40aloha.net=3E on the north =
shore of Kauai
=3E
=3E ---------------------
=3E Deborah A. Bouchette
=3E principal=40aleatoric-art.com
=3E +1.503.690.2448 phone/fax
=3E
=3E -----Original Message-----
=3E From: Gary Elfring =5BSMTP:ge=40elfring.com=5D
=3E Sent: Tuesday, March 30, 1999 4:48 AM
=3E Subject: Zinc crystal glaze help??
=3E
=3E ----------------------------Original message----------------------------
=3E I have been lurking on this list for some time,
=3E but have never responded or asked a question. I
=3E have been taking ceramics classes at our local
=3E community college for 3 years now.
=3E
=3E Several of us in class would like to try our hand
=3E at making a zinc crystal glaze and growing those
=3E beautiful crystals. I have bought several pieces
=3E in blue and green that used this type of glaze.
=3E
=3E However, no one at the college has ever done this,
=3E so we are on our own. We have all the equipment and
=3E chemicals we could want, but need a glaze recipe
=3E and some ideas on how to do the firing and cooling.
=3E
=3E We typically fire things here in a gas kiln to cone
=3E 10 (reduction), but we have numerous kilns and can
=3E also do electric, and to any cone.
=3E
=3E Is there any source of information and/or glaze
=3E formulas available for doing this? Any help would
=3E be greatly appreciated.
=3E
=3E Elfring Soft Fonts, Inc. http://www.elfring.com
=3E http://www.barcodingfonts.com http://www.micrfonts.com
=3E Bar Codes, MICR, Signatures, plus popular TrueType fonts and clip art.
--
Marcia Selsor
selsor=40imt.net
http://www.imt.net/=7Emjbmls
http://www.imt.net/=7Emjbmls/spain99.html
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