Service manual

sume that the firing chamber is
cold. On digital kilns, this will re
-
sult in an over-fire. When loading
the kiln, check that the rod ex
-
tends into the firing chamber by
1” or more.
Vacuum the Kiln
Clean the kiln interior before
firing glass, enameling, or ceramic glaze. (Cleaning is not
necessary when firing silver or gold clay.) Use a soft brush
nozzle on a vacuum cleaner. Vacuum the element grooves to
remove debris, which could damage the element.
Removing Hot Ware
To remove hot ware
from the kiln, turn off
the kiln. Tilt the kiln
upward about 1” by lift
-
ing the electrical box.
Carefully slide an
enameling fork under
the shelf or enameling
rack. Place the hot
shelf/rack onto a large
ceramic kiln shelf in front of the kiln. Wear thick work gloves.
Firing Log Book
Record the following information in a firing log book:
I
Date
I
Digital: Firing speed and Hold or Ramp/Hold program
I
Starting time
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Total firing time
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Type of pieces
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Firing results
As you gain experience, you will find a wealth of informa
-
tion in your firing records.
Low Temperature Holds (Digital Kilns)
A low temperature hold (i.e. 200° - 300°F) is more diffi
-
cult to maintain than higher temperature holds (1400° -
1700°F). At low temperatures, turning on the heating ele
-
ment affects firing temperature to a larger degree than at
high temperatures.
When holding at a low temperature, heat the kiln slowly.
Otherwise the temperature may overshoot the hold temper
-
ature before the element turns off.
Avoid Contaminating the Heating Element
Contact with silica or silica bearing compounds, such as
kiln wash, glass separator, alumina hydrate, glass, enameling
powder, and ceramic glaze, will ruin the heating element.
Note: If glaze or glass drips onto a firebrick wall, dig
out the glaze with a screwdriver. Otherwise it may
melt into a brick groove during the next firing and
ruin the element.
The Effect of Silver Residue on Glass
Firing silver clay leaves traces of silver in the firebricks.
Sometimes there is enough silver residue in the kiln to affect
glass colors. For instance, green might turn yellow.
Note: Before firing an important glass piece in a
kiln used for silver clay, perform color tests. Fire
small samples of each glass color on a base sheet of
clear glass. See pages 7 - 9.
Loading the Kiln
Place Ware on the Kiln Bottom or
on a Protective Shelf
Ceramics can be
fired directly on the
firebrick bottom or
on a shelf. Fire glass
only on a shelf or
mold, never directly
on the brick bottom.
Types of shelves
and containers:
Fireclay Shelf
Ceramic fireclay shelves, available from Paragon, protect
the firing chamber bottom and provide a smooth surface.
Use a ceramic shelf in your kiln to fire ceramics, glass, and
china painting.
Insulating Firebrick
Piece
Insulating firebricks
are porous, light-weight,
and can be shaped to sup-
port delicate silver clay de-
signs. Carve the firebrick
with a knife or hacksaw.
Ceramic Bowl
You can purchase an unglazed, small ceramic bisque
bowl from a ceramic supply store. The bowl will last through
many firings. Use it to hold alumina hydrate for silver clay
pieces. You can also shape hot glass by slumping it into the
bowl.
Applying Glass Separator or Kiln Wash
The kiln shelf, kiln bottom, and sagging mold must be
coated with glass separator to
keep glass or ceramic glaze from
sticking to them.
A coat of glass separator or
kiln wash will usually last
through several firings. When
the shelf coating begins to crack
or chip, apply a fresh coat.
When recoating a shelf, re
-
move most of the old coating
with grit cloth (available from
Paragon). This is an abra
-
6/
Separator lasts through sev
-
eral glass firings. Apply new
separator when the old coat
begins to flake.