Specifications

During normal use of the kiln, corrosion will occur on
the metal surfaces, which can cause the kiln to misfire. The
tube assembly should be replaced periodically depending on
the amount of firing done. To extend the tube assembly life,
keep the lid propped during the early stages of firing and do
not close all the peepholes. It is also normal for glaze to
accumulate in the tube assembly; check this periodically.
Kiln sitters, safety timers and computers cannot fully
replace the operator. Mechanical devices do fail, even
though they appear to be in perfect working condition. To
minimize errors, always use shelf cone. Avoid leaving the
kiln unattended, so you can catch costly mistakes.
Eight Common Problems
The cost of the kiln and firing is very high relative to the
cost of the cones. Here are eight good reasons for using shelf
cones in addition to using a kiln sitter, kiln timer and/or
computer.
• Something can fall onto the sensing rod.
•Crumbs from exploded ware or from the firebrick can
get into the tube assembly.
•Kiln wash on the cone or tube assembly can prevent the
cone from bending.
•Using the wrong (or a previously used) cone can be
mistakenly placed into the sitter.
•Acone can become dislodged or allowed to come in
contact with the porcelain tube.
•Cones mishandled roughly, dropped or moistened will
crack and bend too early.
• The weight (hammer) of the sitter may not have
engaged the claw when the cone is placed in it.
• Something can get in the way and prevent the weight
(hammer) from falling when the cone bends.
Safety Timer
The safety timer is a back up shut off device that turns
the kiln off if the kiln sitter fails. This clock shuts off the
kiln after a given time, insuring that severe damage does not
occur. Set the safety timer for approximately 30 minutes
longer than the estimated firing time; this allows for power
influxes and the size of the load. If the timer is set at more
than an hour, it will not turn the kiln off in time to prevent
damage from occurring. To ensure the life of your kiln and
pieces, safety timers are worth the small initial investment
when you purchase your kiln.
Controllers
Kiln controllers automatically fire a kiln using an
electrical signal from a thermocouple (sensor) located in the
kiln. The signal is converted into a temperature and compared
with a program, allowing the controller to decide when to
send current to the heating elements and for how long.
Benefits of using a controller include:
• Automatic, repeatable and accurate control of kiln
• Uniform kiln temperatures with zone control
• Easy to use with many features
Pyrometer
A pyrometer is a device that measures temperature
only. It cannot replace a pyrometric cone, because both
time and temperature are required to ensure the "heatwork"
of the kiln. A pyrometer is useful in determining the inside
temperature of the kiln for advancement of switches or
gauging the cooling process.
Kiln Furniture
Kiln furniture consists of the posts, shelves and supports
(stilts) that are used during firing. These pieces are high
temperature resistant refractory materials that provide support
to the pieces during the firing. Use three posts in a tripod
formation to evenly hold a shelf. Each half shelf should rest on
three posts as well. Posts of proportional size should be used
for added height to ensure stability. Do not use cracked shelves
or posts as they could break apart during the firing, ruining
several layers of ware and the kiln. If a crack should develop
in a shelf because of a hard blow, finish breaking it and use it
as a partial shelf.
Kiln Wash
Kiln wash is a protective coating applied to the top
surface of the shelves. This coating provides a layer of
protection against glaze and other higher firing clays from
adhering to the kiln shelf.
9
Firing
Push Plunger in to
activate kiln.
View A
View B
Sensing
Rod
Cone
Supports
Porcelain Tube
Proper Formation of Cones in Well-Adjusted Kiln Sitter
Underfired OverfiredCorrect Adjustment
Approximately 90˚
angle
View C