David Woof on thu 12 apr 12
Hi Scott=3D2C
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just this morning I stumbled on to reference of a feature article Nils Lou =
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wrote on "Self Glazing Porcelain" for the April 1984 issue of Ceramics Mont=
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hly. However some person past had torn out the article=3D2C so...=3D20
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Nils has always given us good and accurate information so I'm sure this wil=
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l be a welcomed addition to your knowledge if you search for it.
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David Woof
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Hi Scott=3D2C To get your self glazing cone 10 body=3D2C you will need to =
deve=3D
lop a very refractory body loaded up with "soluable salts" and shelf storag=
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e time for the salts to migrate to the surface of the clay. Some years ago =
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I found a naturally occuring clay deposit which contained an abundance of m=
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ineral soluables. At cone 10 it made a very nice Albany/Alberta type slip g=
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laze with the added attractive feature of thousands of tiny micro-craters=
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=3D2C each reflecting a scintilating point of light from their glassy surfa=
ce=3D
. Adding 30% of this clay to a cone 14 body I had developed gave me an attr=
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active self glazing choclate satin to gloss. I set my unglazed=3D2C unbisq=
ue=3D
d=3D2C forms undisturbed on a shelf in a shed for 3 months before firing ra=
w.=3D
The naturally varied atmospheric humidity levels aided in the soluable's m=
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igration to the surface. I kept my forms simple and verticle=3D3B up 18 fir=
ed=3D
inches=3D2C because the clay body was fluxed significantly by the soluable=
s.=3D
Also I did not make forms for domestic utility because the clay started to=
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black core=3D2C though not visably bloated=3D2C at woodfired cones 10-12. =
Thou=3D
gh you can't use traditional Egyptian Paste at the cones you desire=3D2C a =
st=3D
udy of Egyption Paste and the raw materials used to self glaze will demonst=
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rate the reason for and action of the soluables.(mineral salts) Understandi=
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ng this information will point you in the right direction. Let us hear of y=
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our progress and discoveries. David Woof___________________________________=
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______________________________________ From: Scott Steder =3D
@YAHOO.COM>To: Clayart@LSV.CERAMICS.ORG Sent: Monday=3D2C April 9=3D2C 2012=
3:0=3D
8 PMSubject: Cone 10 earthenware Hi ALL=3D2C Been enjoying all the posts th=
is=3D
is my first :) I've been tampering with a few cone 10 iron clay bodies=3D2=
C =3D
with hopes of making a self glazing clay. One that will react nicely in a w=
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ood kiln=3D2C my two formulas have included 10 percent of redart in one and=
1=3D
2 percent in the other. There is 10 percent Neph sy=3D2C and 10 percent sil=
ic=3D
a as well. To try and keep the clay body from slumping/bloating/melting I a=
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dded kyanite to the batch=3D2C about 20 percent. Understanding that it is a=
v=3D
ery refractory material (aluminum silicate) figured it would help=3D2C I ju=
st=3D
havent found much liturature on it being added to earthenware bodies. I've=
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done cone 6 electric tests and they are not fully matured=3D2C although im=
s=3D
till weary about the reaction it will have in reduction atmosphere. Any adv=
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ice/experience with high fire earthenware clay bodies would be most apprici=
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ated. Thanks ! Scott Steder =3D
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