Specifications

Problem Cause Solution
Glazes
Oops, Now What Do I Do?
Problems, Causes and Solutions
21
Glaze crawls on inside vase.
Usually caused by deposits of clay
dust in bottom of piece.
Check the inside before glazing and
remove any dust from inside the vase.
Sometimes can be corrected by
thinning glaze and reapplying to bare
spot and re-firing to original shelf
cone.
Crackle glaze piece splits after or
during firing.
Same as above in #3 When applying crackle glaze to the
outside of a piece, bring (apply) the
glaze over into the inside about 1 inch
to help alleviate this problem.
Vase, cup or tall vertical piece
cracked in kiln.
a. Thermal shock or expansion of two
or more glazes.
b. Incompatible glazes from
different manufacturers.
c. Too heavy of glaze in bottom of the
piece.
a. Try to use the same type of glaze
inside and out when glazing. It's
better to use gloss glaze inside
pieces, even if matte is used
outside. Do not use matte glaze
inside and a gloss outside.
Exceptions are Series 2000.
b. Use glazes from the same
manufacturer to assure compati-
bility.
c. After rolling glaze on inside of
piece, invert piece to drain excess
glaze.
Clear glaze shows green, brown and/or
black specks after the glaze fire.
a. Dirty or corroded ferrule of the brush.
b. Brushes used for stains and then
glazes.
a. Black and brown specks are from
iron rust; green is from the nickel
coating on the ferrule. Do not allow
brushes to stand in water.
b. Do not use the same brushes for
metallic stains and glazing a piece.
Metallic particles left in brush can
contaminate the glaze.
Glaze crawls and leaves bare spots.
a. Caused by dirt, dust or oil.
b. Color is too old to use.
c. Color has been frozen.
d. Too heavy an application.
a. Make sure piece is clean before
painting by wiping down with a
damp sponge. Keep hands clean.
b. Color preservative has deteriorated
with age. Do not use old product.
c. Sometimes freezing of the product
will destroy the makeup of the
glaze. Do not use glaze after it has
been frozen.
From time to time there are problems that arise during the completion of a piece. This chapter is designed to help
you quickly diagnose the problem, learn the cause and if possible, correct the mishap. The problems are listed in groups
of categories. The problem may be listed more than once in slightly different ways to help you get to the solution.