pletely dry before firing to prevent the possibility of ex-
ploding. To speed drying, make indentions in the clay
with the end of a small brush handle after the cone is in-
serted. Self-supporting cones stand upright without
holders. We recommend self-supporting cones; they are
easier and faster to use than standard large cones.
How to Position Cones on the Shelf
Place your cones on a shelf behind the peephole. If the
size of your ware does-
n't permit placing a
shelf in the kiln at
peephole level, use a
post to raise the cones.
Place the cones 8"
away from the
peephole. Posi-
tioning them closer
makes them diffi-
cult to see and may
also subject them
to cool air drafts.
Have enough space around the cones to keep them
from touching a piece of ware when they bend.
Position cones so that when viewed from the peep-
hole, they are silhouetted by an element on the op-
posite kiln wall. (Keep cones at least 2" from an el-
ement.)
The element that silhouettes the cones should be
level with the lower part of the cone. If the element
is in line with the upper part of the cone, you won't
be able to see the cone when it bends.
If you use the three-cone system, always have the
higher temperature cone on the same side in every
firing. Otherwise you can lose track of which cone
is which.
Wear kiln firing safety glasses when viewing the
cones through the peephole.
The Bending of the Cone
The large standard and self-supporting witness cones
have reached maturity when the tip bends to the 6 o'clock
position.
Large standard cone: The tip should bend straight
down until it just begins to touch the cone holder.
Self-supporting cone: The
self-supporting cone should
bend downward until the tip is
even with the top of the base.
The tip should be about 1/2"
above the shelf surface.
FIRING ACCESSORIES
Shelves
Shelves are flat
slabs of fireclay that
have been fired to a
higher temperature
than will be encoun-
tered in your kiln.
With
multiple
shelves you can
stack more ware in
your kiln than you
could ever place on
the bottom of the kiln alone.
Posts
Posts are made from the same material as shelves.
Posts support and separate the layers of shelves in a kiln.
The shorter the post, the greater the stability. Posts can
be stacked upon one another to achieve a greater height,
but a single post is more stable.
All Purpose, High Fire Kiln Wash
High fire kiln wash is a mixture of finely ground min-
erals that do not fuse at porcelain and stoneware temper-
atures. It acts as a barrier between the shelf and dripping
glaze. The kiln shelf must be coated with kiln wash to
keep ceramic glaze and glass from sticking to it. Without a
barrier, the glaze would embed permanently into the
shelf.
Caution:
Do not apply kiln wash to the kiln walls
or lid. Contact with kiln wash will destroy heating
elements.
Brush kiln wash on the tops of kiln shelves and on the
kiln bottom to prevent glaze drippings from sticking per-
manently to these surfaces. As a powder, high fire kiln
wash has an unlimited shelf life.
PREPARING TO FIRE
THE KILN
Vacuuming the Kiln
Note:
Do not breathe brick dust. Vacuum the kiln
with a HEPA filtered vacuum cleaner or a central
vacuum that takes the dust outside.
One of the easiest kiln maintenance tasks you can per-
form is regular vacuuming. Vacuum the kiln before every
glaze firing. This helps to prevent dust particles from
landing on glazed ware during firing. Vacuum every four
bisque firings.
Use the soft brush nozzle on a vacuum cleaner. Be
sure to vacuum the element grooves, the inner surface of
the kiln lid or roof, and the underside of kiln shelves.
5
The self-supporting cone
bent to maturity.
Self-supporting cones silhouetted by
an element.
