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Glazing Techniques
lazes
can be applied in various ways. Some glazes must be applied in certain
ways and not in others. The following is a description of the most common
glazing techniques.
Dipping
Dipping is probably the most common glazing technique. As the name suggests,
a pot or other ceramic object is dipped into a bucket of glaze. This may
require a large amount of glaze, depending on the size of the object.
If it is a thin necked vase or bowl that is being glazed, the inside may
be done first by pouring the glaze in and out again. Then the form is
dipped into the glaze with the opening facing down. The trapped air will
prevent any glaze entering the already glazed interior.
Hint: three-pronged raku tongs are handy for dipping -- they leave only
small pin-sized marks which can be smothed over by rubbing.
Pouring
Pouring is a technique which may be used if a work is too large to dip,
or if there is just not enough glaze available. The ceramic object is
held in one hand and glaze is poured over it as evenly as possible, until
the whole surface is covered. With this method, overlapping is inevitable.
If this is an issue with the glaze used, edges may be smothed over by
rubbing with a finger.
Hint: do not rub glazes with unprotected fingers if they contain toxic
ingredients like lead, manganese
or even copper! (Try rubber gloves.)
Spraying
Separate equipment is required for spraying, which is not always available
in the studio pottery: a glaze spray gun, a compressor, a mask and a glaze
booth. The glaze booth extracts fine glaze mist, which should not
be inhaled from the air. This is done with an extractor fan. More sophisticated
spray booths have a wall of running water to trap most of the glaze, so
it is not just ejected into the atmosphere (important where toxic ingredients
are used!). Spraying may sound easy but is not necessarily. Spraying the
interior of a vase for example would be difficult, as the spray has little
room to maneuver in the small space and is ejected again quickly, possibly
spraying into your face. To remedy this, such vessels are first poured
and the exterior sprayed afterwards. The advantage to spraying is that
glaze cover is very even. This can be crucial with some glazes.
Hint: to check the thickness of the sprayed glaze, scratch the surface
with a pin. If it is of sufficient thickness, the scratch can be smoothed
over by rubbing.
Brush-on Glazes
Brush-on glazes are glazes especially formulated for brushing onto ceramic
work. This makes decorating very easy. These glazes are formulated so
that brush marks will largely smooth over, but at the same time the glaze
won't run, if fired to the right temperature. Brushing on glazes also
enable variations in decoration, that would otherwise be impossible. The
difficulty is getting the combination of thickness and firing temperature
right, but this is -- as with so may things -- a matter of trial and error.
General Rules
For health reasons, it is important that you read the general
rules for handling toxic materials when glazing ceramic work.
Hint: find out about glaze defects and their remedies!
Free glaze recipes are available at Glaze
Page!
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