Don Goodrich on thu 11 mar 99
David,
Glad you mentioned the portland cement idea. Awhile back I ran across an
analysis for it in an old Materials Handbook:
(ingredients by percent)
2.9 MgO
63.2 CaO
6 Al2O3
21.3 SiO2
2.7 Fe2O3
1.8 SO3
So out of curiosity calculated a glaze using it:
15 Portland cement type 1
15 Flint
15 Gerstley borate
10 Talc
20 EPK
25 Custer feldspar
This falls within limits for a c5-6 satin but takes a lot of added ingredients
to balance all that calcium and provide enough alumina. No, I've never mixed
up a test batch of the stuff. This is mainly because there hasn't been any
cement around the house and there are more convenient ways to get the same
combination of oxides.
The point your professor may have been making, and that Martin's post
regarding plant ashes also makes, is that glaze materials are where you find
them. It's a useful point to get across to students, since it deepens our
consciousness of what we're working with. For awhile now I've suspected one
could make a workable ceramic by using kaopectate, toothpaste, and
baby powder although it would be a rather pricey choice of materials. Anybody
got an analysis for Colgate?
Cheers,
Don Goodrich
goodrichdn@aol.com
David Hendley wrote:
>>..As somewhat of a showman, my professor in college liked to
make glazes from cement.
BTW, you can also make glazes with regular portland cement;
just be sure you don't dawdle too long while glazing your pieces.<<
Martin Howard wrote:
>> I now have good clear glazes using cat litter
and the slop from cutting granite memorials, plus a low cone borax frit.
But, if we only knew more plant ash analyses, then, linking that
knowledge with our knowledge of what elements produce which colours, we
could well have a list of plant ashes, including lichen, ferns, grass,
straw, different hedge clippings (which are often a problem to dispose
of in small gardens).<<
Dwiggins, Sandra (NCI) on fri 12 mar 99
In the old CM monograph by Richard Behrens on glazes, he has a bunch that are
formulated with Portland Cement.
Sandy D.
-----Original Message-----
From: Don Goodrich [SMTP:GoodrichDn@aol.com]
Sent: Thursday, March 11, 1999 4:45 PM
To: CLAYART@LSV.UKY.EDU
Subject: Odd ingredients, showmanship
----------------------------Original message----------------------------
David,
Glad you mentioned the portland cement idea. Awhile back I ran across an
analysis for it in an old Materials Handbook:
(ingredients by percent)
2.9 MgO
63.2 CaO
6 Al2O3
21.3 SiO2
2.7 Fe2O3
1.8 SO3
So out of curiosity calculated a glaze using it:
15 Portland cement type 1
15 Flint
15 Gerstley borate
10 Talc
20 EPK
25 Custer feldspar
This falls within limits for a c5-6 satin but takes a lot of added ingredients
to balance all that calcium and provide enough alumina. No, I've never mixed
up a test batch of the stuff. This is mainly because there hasn't been any
cement around the house and there are more convenient ways to get the same
combination of oxides.
The point your professor may have been making, and that Martin's post
regarding plant ashes also makes, is that glaze materials are where you find
them. It's a useful point to get across to students, since it deepens our
consciousness of what we're working with. For awhile now I've suspected one
could make a workable ceramic by using kaopectate, toothpaste, and
baby powder although it would be a rather pricey choice of materials. Anybody
got an analysis for Colgate?
Cheers,
Don Goodrich
goodrichdn@aol.com
David Hendley wrote:
>>..As somewhat of a showman, my professor in college liked to
make glazes from cement.
BTW, you can also make glazes with regular portland cement;
just be sure you don't dawdle too long while glazing your pieces.<<
Martin Howard wrote:
>> I now have good clear glazes using cat litter
and the slop from cutting granite memorials, plus a low cone borax frit.
But, if we only knew more plant ash analyses, then, linking that
knowledge with our knowledge of what elements produce which colours, we
could well have a list of plant ashes, including lichen, ferns, grass,
straw, different hedge clippings (which are often a problem to dispose
of in small gardens).<<
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