David Woof on wed 11 apr 12
Hi Scott=3D2C
=3D20
To get your self glazing cone 10 body=3D2C you will need to develop a very =
re=3D
fractory body loaded up with "soluable salts" and shelf storage time for th=
=3D
e salts to migrate to the surface of the clay.
=3D20
Some years ago I found a naturally occuring clay deposit which contained an=
=3D
abundance of mineral soluables. At cone 10 it made a very nice Albany/Albe=
=3D
rta type slip glaze with the added attractive feature of thousands of tiny =
=3D
micro-craters=3D2C each reflecting a scintilating point of light from their=
g=3D
lassy surface.
=3D20
Adding 30% of this clay to a cone 14 body I had developed gave me an attrac=
=3D
tive self glazing choclate satin to gloss.=3D20
=3D20
I set my unglazed=3D2C unbisqued=3D2C forms undisturbed on a shelf in a she=
d fo=3D
r 3 months before firing raw. The naturally varied atmospheric humidity lev=
=3D
els aided in the soluable's migration to the surface.=3D20
I kept my forms simple and verticle=3D3B up 18 fired inches=3D2C because th=
e cl=3D
ay body was fluxed significantly by the soluables. Also I did not make form=
=3D
s for domestic utility because the clay started to black core=3D2C though n=
ot=3D
visably bloated=3D2C at woodfired cones 10-12.
=3D20
Though you can't use traditional Egyptian Paste at the cones you desire=3D2=
C =3D
a study of Egyption Paste and the raw materials used to self glaze will dem=
=3D
onstrate the reason for and action of the soluables.(mineral salts) Unders=
=3D
tanding this information will point you in the right direction.
=3D20
Let us hear of your progress and discoveries.
=3D20
David Woof
_________________________________________________________________________=
=3D20
=3D20
=3D20
From: Scott Steder To: Clayart@LSV.CERAMICS.ORG S=
=3D
ent: Monday=3D2C April 9=3D2C 2012 3:08 PMSubject: Cone 10 earthenware Hi =
ALL=3D
=3D2C Been enjoying all the posts this is my first :) I've been tampering =
wi=3D
th a few cone 10 iron clay bodies=3D2C with hopes of making a self glazing =
cl=3D
ay. One that will react nicely in a wood kiln=3D2C my two formulas have inc=
lu=3D
ded 10 percent of redart in one and 12 percent in the other. There is 10 pe=
=3D
rcent Neph sy=3D2C and 10 percent silica as well. To try and keep the clay=
b=3D
ody from slumping/bloating/melting I added kyanite to the batch=3D2C about =
20=3D
percent. Understanding that it is a very refractory material (aluminum sil=
=3D
icate) figured it would help=3D2C I just havent found much liturature on it=
b=3D
eing added to earthenware bodies. I've done cone 6 electric tests and they=
=3D
are not fully matured=3D2C although im still weary about the reaction it w=
il=3D
l have in reduction atmosphere. Any advice/experience with high fire earth=
=3D
enware clay bodies would be most appriciated. Thanks ! Scott Steder =
=3D
=3D
| |
|
