Patsy Catsos on fri 4 oct 96
Hello clayart friends:
I am working with a cone 6 glaze that I really love, but the results vary
tremendously with the thickness of the glaze application. Too thin and the
glaze is too transparent. Too thick and it cracks excessively as it dries
and crawls during the firing. I measure the density of the wet glaze and
that helps some, and I try to keep other factors about the same. I am
dipping, by the way. I would appreciate any and all advice on testing for
glaze thickness and/or reducing pre-firing cracking in the glaze. Have you
tried Axners glaze thickness tester? Thanks.
Patsy Catsos
Cape Elizabeth, Maine
patsycats@aol.com
Anglersnet on sun 6 oct 96
I'm not familiar with the thickness tester you mentioned, but I am
familiar with using an Ames gauge to measure glaze thickness. It is
commonly used in the pottery industry. Generally there is a point in the
center of the gauge that penetrates the glaze surface. The gauge frame
itself remains on the glaze surface and the depth of penetration (glaze
thickness) is measured with an analog or digital gauge. I suppose it
would only work on flat surfaces. Remember also that the galze coating
can have a variable density, especially when spraying so thickness is only
an approximate method for determining the actual deposit. Another method,
if you are spraying, is to spray a stickon dot or similar surface at the
same time and weigh the glaze application in grams per square inch or
square centimeters. (more accurate).
You might also investigate making your glaze less prone to cracking and
crawling. Reducing the clay content, if it is high, or substitution of a
less plastic kaolin in place of the place of ball clay may help. If Zinc
oxide is in the formula, that also can be a high shrinkage item and frit
or other substitution may be helpful.
Good Glazing, Bob Jameson
Paulaclay@aol.com on sun 6 oct 96
I've never used the Axner glaze thickness tester, as I always try to do
without gizmos. I teach my students the fingernail test. Dip your finger in
the glaze. If the glaze runs off showing all of your nail, it's too thin. If
you can't see the outline of your nail, it's too thick. But if it sticks to
your finger and you can see the OUTLINE of your nail, it's just right. You
can equate this to the thin/thick characateristics of your particular glaze.
Paulaclay@AOL.com, Paula Sibrack, Sherman, CT
Marcia Selsor & Matt Benacquista on sun 6 oct 96
Paulaclay@aol.com wrote:
>
> ----------------------------Original message----------------------------
> I've never used the Axner glaze thickness tester, as I always try to do
> without gizmos. I teach my students the fingernail test. Dip your finger in
> the glaze. If the glaze runs off showing all of your nail, it's too thin. If
> you can't see the outline of your nail, it's too thick. But if it sticks to
> your finger and you can see the OUTLINE of your nail, it's just right. You
> can equate this to the thin/thick characateristics of your particular glaze.
> Paulaclay@AOL.com, Paula Sibrack, Sherman, CT
I use the dry knuckle test same as discribed by Paula.
Marcia in Montana
--
Marci Selsor
Matt Benacquista
http://www.imt.net/~mjbmls/
mjbmls@imt.net
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