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glaze tests, general, for mastering cone 6 glazes,

updated wed 10 apr 02


Alisa og Claus Clausen on tue 9 apr 02

by John Hesselberth and Ron Roy

Dear Clayart,

Looking at 50 test tiles standing in their rows according to base glaze
from the above book,
I am very pleased with the results. I have 100 percent success in regard
to the surface, color and fluidity of
the glaze. In addition, I think every glaze has it's merit
aesthetically. For the beginner or experienced
ceramist, there is an entire pallet of glazes within these pages, whether
you choose one base and color it,
or mix up 6 to 10 of the recipes as they appear in the book.

During my last visit to the states, I purchased Frits 3134, 3124 and 3195
so that I could properly mix these glazes. Then I made a test using only
the Frit I generally use, to see if I could use these glazes with local
materials. The glazes turned out well with the substitutions of my local
materials. The tiles with the recipe Frit and the tile with the Frit I
use, 623, are almost identical visually. My Frit gives slightly more melt
in the surface, but no dripping. Some tiles showed a fraction more
streaking and pooling in the ridges of the tiles.

The results of these tests will be given in a following post, as book
reference, page, any subs. if any in the recipe and then a description of
the result I have. I know it will be lengthy, but hopefully concise enough
to read through. Just as I can best describe the tiles.

My question is why do we say that glazes do not travel? I think these
traveled fine. Sometimes there are few wrinkles to work out, but every one
of these fired up well.

The book is generously packed and open about technical matters and working
and testing methods. Already on page 29 I was able to solve one of my
frustrating mysteries of my liner glaze. It was over-flocculated and I did
not know what that was. I thought it was too thick. I added water, with
it resulting a too thin covering. From this books information I have it
fixed and it is in steady use again. There are so many other keys to locks
that I could not work out. Very useful reference. I am impressed with the
glazes smoothness and feel. Not one showed any surface faults such as
pinholes or crazing. There are many good semimattes that have otherwise
been the most difficult glazes for me to get right. I also am pleased with
the amount of glosses that are covering as opposed to
translucent. Personal preferences.

From these glaze recipes a ceramist could have an instant pallet of a
blue, brown, white, clear, red, black and green, semi mats, mats and
glosses. I personally think a real plus about the majority of these glazes
is that they melt evenly despite some intentional uneven applications and
that they are so well covering. I am glad that I have been through a few
tests before these to appreciate the bad from these really good tests.

Best regards, Alisa in Denmark