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differences between test tiles and pots.

updated thu 26 may 05


Lee Love on wed 25 may 05

Phil Davenport wrote:

>I have done some testing of the glazes listed in the Mastering Cone 6
>book and am seeing a couple of problems. One is pin holes. I am doing
>a 20 minutes soak. Should I go longer? Is anyone else having this
>I noticed some pin holes, as the glaze dried, and rubbed those areas
>with my finger.
Phil, You don't explain how you cleaned the bisque. Pin holes that are
evident after glazing (before firing) can be eliminated by sponging the
bisque with water.

>None of my test pieces had the bare spots and I was doing the 20 minute
>soak. About the only difference is the thickness of the glazes. When
>doing the initial testing the glazes were thicker. Since then I have
>added additional water to the glazes.
Absolutely, glaze thickness will effect the final outcome of the fired
glaze. You should test your glaze at several thickness. If you make two
test tiles for each test, scratch the surface of the glaze to see its
thickness. Keep one of the two tests back and a sample. When your test
comes out how you want it, use the unfired tile to measure future
applications against.

Also, if you tests are of a different thickness compared to the "whole
pots" you glaze, the test will not necessarily look the same as the pot.
Thin bisque picks up less glaze than thick bisque does.

You can either siphon or ladle water off the top of the glaze buck after
the glaze settles if yo have too much water in it. I always have a thick
mix of my main glaze on hand to add to the working batch, in case it
gets too thin, to add to the working batch.

李 Lee Love 大
愛      鱗
in Mashiko, Japan Visual Bookmarks Zen and Craft

"With Humans it's what's here (he points to his heart) that makes the difference. If you don't have it in the heart, nothing you make will make a difference." ~~Bernard Leach~~ (As told to Dean Schwarz)