Paragon Ceramic Fiber Jewelry Kiln Instruction & Service Manual

Paragon Ceramic Fiber Jewelry Kiln Instruction & Service Manual
Ceramic Fiber
Jewelry Kiln
Instruction &
Service Manual
You are about to enter the magical
world of kiln-fired jewelry. To
safely find your way around and to
master your kiln, read this manual.
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Thank you for choosing a Paragon kiln! We have designed it to give
you many years of reliable service.
This manual includes answers to the
most common questions we have been asked; reading it will ultimately save you time and help you master your kiln. Your instruction
packet also includes a separate digital controller manual. Please save
both manuals.
When you receive your kiln, check the carton for
damage. Check the kiln for both interior and exterior damage. If the
kiln is damaged, you can refuse the shipment and have it returned, or
accept the shipment after having the driver note the damage on the
Bill of Lading. Then call Paragon at 800-876-4328 or 972-288-7557
(open Monday to Thursday, 7 A.M. to 5:30 P.M. Central).
Check the Bill of Lading to insure that you received the correct
number of packages. Note any shortages on the Bill of Lading, and
have the driver sign the copy. If there were no signs of visible kiln
damage and you discover it after the driver has left, notify the shipper
It was carefully designed to provide
maximum protection during shipping. Use the carton to take the kiln
to seminars or on vacation, or to return the kiln to the factory for
Tremendous stresses are generated within
the kiln. The ceramic fiber firing chamber actually expands and contracts with each firing. Do not be concerned if small cracks appear in
the fiber. This is normal. These are surface cracks that close tightly
when the heated fiber expands. You may find a small pin hole in the
center of the firing chamber. It is from the manufacturing process
and will not affect the kiln’s performance.
The paint and the ceramic fiber around the door will eventually discolor from heat. This will not affect the kiln’s performance.
During firing, you will hear an intermittent, distinct clicking. This is
the sound of the relay(s) sending power to the heating elements. Do
not be concerned with this sound.
During the first few firings, you may also smell an odor from your
kiln. This is normal and is caused by the burning of binders in the ceramic fiber firing chamber. This odor is accompanied by a discoloration, which will disappear after the kiln reaches 1000°F.
Important information about your kiln
is recorded on its electrical data plate, which is attached to the side of
the kiln. Please include this information when ordering parts or calling your dealer or the factory about your kiln.
Special thanks to Ed Biggar, Martha Biggar, Sallie Bly, and Patricia
Walton for their many suggestions.
©2001, by Paragon Industries, Inc. IM-164/1-13
Basic Kiln Set Up
Basic Operation
Silver & Gold Clay
Glass Fusing & Slumping
Annealing Beads
Enameling on Metal
Ceramic Overglaze & Decals
Lost Wax Burnout
Firing Mistakes
Kiln Maintenance
Electrical Installation . . . . . . . . . . . . . . . . . 4
Where to Locate the Kiln . . . . . . . . . . . . . . 4
How to Transport the Kiln . . . . . . . . . . . . . 4
Accessories . . . . . . . . . . . . . . . . . . . . . . . . 5
Important Guidelines . . . . . . . . . . . . . . . . . 6
Loading the Kiln . . . . . . . . . . . . . . . . . . . . . 7
Venting the Kiln . . . . . . . . . . . . . . . . . . . . . 9
Looking Into a Hot Kiln. . . . . . . . . . . . . . . . 9
Drying Time . . . . . . . . . . . . . . . . . . . . . . . . 10
Loading the Kiln . . . . . . . . . . . . . . . . . . . . 10
Venting the Kiln . . . . . . . . . . . . . . . . . . . . . 10
Rate, Temperature, Hold. . . . . . . . . . . . . . 10
Cooling the Piece . . . . . . . . . . . . . . . . . . . 11
Combining Silver Clay
With Other Materials . . . . . . . . . . . . . . . . 11
Frequently Asked Silver Clay Questions. . 11
How to Cut Glass . . . . . . . . . . . . . . . . . . . 13
Fusing Compatibility of Glass . . . . . . . . . . 13
The Annealing Range . . . . . . . . . . . . . . . . 14
Cleaning and Gluing the Glass . . . . . . . . . 14
Loading the Kiln . . . . . . . . . . . . . . . . . . . . 14
Firing the Glass . . . . . . . . . . . . . . . . . . . . . 14
Preparing and Decorating the Copper . . . 16
Firing Enamel . . . . . . . . . . . . . . . . . . . . . . 17
Pyrometric Cones . . . . . . . . . . . . . . . . . . . 17
Loading and Firing Overglaze. . . . . . . . . . 18
Silver Clay, Glass . . . . . . . . . . . . . . . . . . . 20
Ceramic Overglaze . . . . . . . . . . . . . . . . . . 21
Please visit for videos on
maintaining your kiln.
Circuit Breaker Trips . . . . . . . . . . . . . . . . . 21
Temperature is Inaccurate . . . . . . . . . . . . 21
Temperature is Uneven. . . . . . . . . . . . . . . 21
Changing the Door . . . . . . . . . . . . . . . . . . 22
Door Latch Spring Adjustment . . . . . . . . . 22
Adjusting a Door That Won’t Stay Shut . . 22
Ceramic Fiber Repair . . . . . . . . . . . . . . . . 23
Cleaning or Replacing the
Glass Viewing Port . . . . . . . . . . . . . . . . . . 24
Replacing the Thermocouple . . . . . . . . . . 24
Replacing a Relay or Transformer . . . . . . 25
Replacing the Temperature Controller . . . 26
Testing the Heating Element. . . . . . . . . . . 26
Repairing an Element Connector . . . . . . . 27
The warranty on your Paragon kiln does
not cover damage from overfiring,
regardless of the circumstances. It is the
operator’s responsibility to make sure
the kiln turns off at the proper time.
The Ceramic Fiber
Avoid touching the firing chamber
surface with sharp or pointed objects.
They can damage the fiber surface.
Touching the embedded heating
element with sharp or pointed objects is
a shock hazard.
Read the Manual!
Do not leave kiln unattended while firing.
Wear safety glasses when cutting glass.
Read each page of this manual in detail
before operating your kiln. Warranty
does not cover damage caused by
failure to follow instructions.
Food or Drink Surfaces
Some decorative materials may be
unsafe and toxic when used for surfaces
that will be in contact with food or drink.
When you m ake food or drink
containers, select a glaze or glass that
has been formulated, tested, and
labeled as approved for surfaces that
will be in contact with food or drink.
Follow the glaze or glass manufacturer’s
instructions exactly, without any
Important Safety Rules
An electric kiln is extremely safe to operate provided you follow these basic safety rules:
Unplug kiln when not in use.
Do not touch hot sides.
Keep unsupervised children away.
Place kiln on a non-combustible surface.
Do not install closer than 12” from any wall or combustible surface.
Fire only in a well ventilated, covered and protected
Keep cordset away from hot sides of kiln.
DANGEROUS VOLTAGE: Do not touch heating
elements with anything.
Wear green #3 firing safety
glasses, and keep your face at
least 15” away when looking
into a hot kiln.
Keep food away from your work area.
Never fire tempered glass inside a kiln. It could explode.
Avoid firing toxic materials inside the kiln, such as
styrofoam (used as a core for hollow beads).
When firing cork clay as a filler, keep the kiln door
closed between 500° - 800°F / 260° - 426°C. This is to
prevent the cork from flaming out.
Keep the kiln door
closed when the kiln
is not in use. This
keeps dust out of the
kiln. Also, should
someone turn on the
kiln while you are
away, the closed door
will keep the heat
safely inside the firing
Never place papers and other combustibles on top of
the kiln, even when the kiln is idle. If people become
accustomed to storing objects on the kiln, they may
forget and do that while the kiln is firing.
Fire only approved materials purchased from a
knowledgeable supplier. Do not fire marbles, pieces
of concrete, rocks, and other objects. Rapid heating
to high temperature can cause violent reactions in
many materials.
Greenware, which is unfired clay, must be bone dry
before firing. Moist greenware can explode inside
the kiln, damaging the kiln. Place a piece of
greenware against the inside of your wrist. If it feels
cool, it is too wet to fire.
Store kiln shelves in a dry area. Moist shelves can explode inside a kiln.
If you smell burning plastic, turn
the kiln off. Examine the wall outlet and supply cord for signs of
Remove flammable materials
from the kiln room.
Disconnect kiln before servicing.
Basic Kiln Set Up
Electrical Installation
You must plug your kiln
into a circuit that no other
appliance uses while the
kiln is firing. Turn off the
circuit breaker or unscrew
the fuse for the circuit that
your kiln will be plugged
into. Check to see if other
appliances shut off too. If
that circuit powers appliances that must remain on
while the kiln is firing, plug
your kiln into a different
Note: 120 volt kilns: avoid extension cords if possible. If you must use one, never use one smaller
than 12 gauge and longer than 20 feet. Never plug
it into a ceiling outlet!
Voltage fluctuation can vary firing time from as little as
half to more than twice the average time. If the voltage is
too low, the kiln may never reach full temperature.
The receptacle must have a separate safety grounding
wire. This protects you from serious electrical shock.
Changing the cord plug will void your warranty!
Where to Locate the Kiln
Many people store their kiln on a small steel cart with
casters. When they fire the kiln, they move the cart near
an open window or even take it outside.
Place your kiln in a well ventilated, covered, and
protected area such as the garage, basement,
utility, or hobby room.
Note: Some people keep their kiln outside on a
covered patio. This is okay so long as the kiln is
not subjected to excessive humidity. We recommend good ventilation especially when you fire
decals, china paint, lost wax casting, and silver
clay filler materials such as cork clay. However,
some materials, such as silver clay fired alone,
may not need special ventilation.
Remove gasoline, paint, and other flammable
materials from the kiln room.
Provide a minimum of 12 inches clearance between kiln and the closest wall.
Never allow the room temperature of your firing
room to exceed 100 - 110° F. Measure the temperature about 3 feet from the kiln. If necessary,
use fans to lower room temperature.
Keep the kiln away from curtains or other combustible materials.
Position kiln on a level, fire-proof surface. We
recommend an 18” x 18” piece of sheet metal, a
large ceramic tile, or a large ceramic kiln shelf.
Place the kiln on a fire-proof surface, such as a large ceramic kiln shelf.
Note: If you are with the kiln at all times during
firing, you can place it directly onto a workbench
or kitchen table. A fire-proof surface is ideal,
though, because it provides a safe place to lay hot
shelves removed from the kiln. But remember
that heat can transfer through the ceramic shelf
to the surface underneath.
Keep unsupervised children away.
Keep the power supply cord away from the kiln
When storing the kiln, do not lay flammable materials such as papers on top. It is too easy to forget to remove them when you fire the kiln.
There is little danger of serious burn from accidental
contact if you exercise the same caution you would use
with an electric iron.
How to Transport the Kiln
Some people take their kilns to seminars or on vacation. The easiest way to transport the kiln is to use the
original packing materials.
If you no longer have the packing materials, transport
the kiln on its back with the door facing up. Place a thin
sheet of foam cushioning between the door and the firing
chamber to prevent rubbing. Avoid subjecting the kiln to
excessive vibration during travel.
Basic Operation
Ceramic Fiber Shelves
The soft ceramic fiber shelf, which comes
standard with the kiln,
cradles gold and silver
clay pieces. These
shelves are not suitable
for firing glass or ceramics.
Ceramic Fiber Blanket
Delicate silver or gold clay shapes may need extra support during firing to prevent warping. Place these shapes
on a piece of ceramic fiber blanket.
Stilts are high temperature wire points embedded in a
ceramic base. The points separate enameling and glazed
ceramics from the shelf.
Ceramic Fireclay Shelves & Posts
Ceramic fireclay
shelves, available from
Paragon, are hard ceramic surfaces on
which to fire ceramics
and glass. Firing glass,
enameling, and ceramic glazes directly
on the firing chamber
bottom would ruin the
bottom. Shelves can
be stacked using posts.
Glass Separator & Kiln Wash
Glass separator and
kiln wash are mixtures
of finely ground minerals that will not melt and
fuse together at high
temperatures. They
prevent glass and ceramic glaze from sticking to fireclay shelves.
The main difference
between glass separator
and kiln wash is that the separator is ground more finely
to leave a smooth back to glass pieces laid on the shelf.
As powders, glass separator and kiln wash have an unlimited shelf life. Do not breathe the powder when mixing.
Caution: If glass separator or kiln wash contact a
heating element, that element will burn out in the
next firing. NEVER apply glass separator or kiln
wash to the ceramic fiber firing chamber.
Haik Brush
The haik brush is used to apply
glass separator to the kiln shelf in a
smooth, thin layer. The smoother
the glass separator, the smoother
the underside of the glass.
The wire mesh above is referred to as an enameling rack. An enameling
fork lifts the rack out of the kiln. A stilt separates the piece from the rack.
Enameling Rack and Fork
Enameling is the art of firing
glass onto metal. The metal
shapes are loaded onto a high
temperature wire rack. The
enameled pieces and wire rack
are loaded into a hot kiln, fired
for just a few minutes, and removed red hot. To load and unload the racks safely, use
an enameling fork or long-handled spatula and a heat-resistant glove.
The heating element under power is dangerous. Do
not touch the element with anything! Turn the kiln
switch off before inserting an enameling fork into the firing chamber.
Pyrolite Fiber Repair Filler
This is a permanent, high temperature refractory cement
used to repair holes or
cracks in the ceramic
fiber firing chamber.
Two Types of
Safety Glasses
Wear clear safety glasses when cutting or chipping glass.
Wear dark green #3 firing
safety glasses when looking
into a hot kiln, such as when
checking the progress of
Firing safety glasses are
specially coated to filter the
infra-red and ultra-violet light
Dark green firing safety glasses.
inside a kiln. They reduce glare, protect your eyes from
heat, and make the kiln interior easier to see.
Caution: Always wear firing glasses when viewing
the interior through the optional glass view port.
Optional Doors
You can replace the
standard door on some
models with these optional
I Bead door for annealing
glass beads
Glass view port for
checking the progress of The bead door and view port comglass fusing or enamel- bination door.
ing. (Note: It is not necessary to visually check silver clay.) You can also check
the glass and enameling with the standard door; just
crack it open for a few seconds. The advantage to the
view port is the convenience.
Bead door and glass view port combination
Ask your dealer if these are available for your kiln. It
takes about 30 minutes, a drill, and a ¼” nut driver to
change doors. (See instructions, page 22.)
Installing the Mandrel Holder for the Bead Door
Open the door.
You will find
two screws on
the bottom
edge of the
door. Loosen
the screws with
a ¼” nut driver.
Bead Door Latch
Raise the bead door latch to
keep the door closed when not
in use. Lower the latch to insert bead mandrels.
Important Guidelines
The Embedded Heating Element
The heating elements of your kiln are embedded into
the ceramic fiber firing chamber. The firing chamber
surface is hardened to a depth of ¼”. This makes the fiber more durable. It is important that you do not touch
the firing chamber with sharp objects. These can penetrate the fiber surface and contact the heating element,
which is a shock hazard.
Caution: The heating element under power is
dangerous. Do not touch the element with anything! Turn the kiln switch off before inserting
an enameling fork into the firing chamber to remove a shelf.
The Clicking Noise
Do not be concerned that your kiln makes a clicking
sound during firing. Your kiln contains a relay, which
sends power to the element. The relay clicks as it cycles
on and off to maintain the correct temperature.
Check Thermocouple
You will find a small rod, called the thermocouple, extending into the firing chamber. The thermocouple
senses temperature. If this rod is pushed out of the firing
chamber, the kiln will assume that the firing chamber is
cold. This could result in an over-fire. Be sure the rod extends into the firing chamber by ½” - ¾” before firing the
Vacuum the Kiln
Slide the two
slots in the bead
mandrel holder
under the two
screws in the
door. Tighten
the screws.
When placing
beads inside the kiln,
rest the bead mandrels on the mandrel
Use a soft brush nozzle on a vacuum cleaner to remove
dust from inside the kiln before firing glass, enameling,
or ceramic glaze. (Cleaning is not necessary when firing
silver or gold clay). Keep the nozzle at least 2” away from
the thermocouple and the controller. Static electricity
from the vacuum cleaner can damage the controller.
Removing Hot Ware
To remove hot ware from the kiln, turn off the kiln by
pressing the switch on the front. Carefully slide an enameling fork or a long-handled spatula under the shelf. Place
the hot shelf on a large ceramic tile or ceramic kiln shelf
in front of the kiln. Wear heat-resistant gloves and safety
Caution: Remember that heat may transfer
through the ceramic tile to the surface underneath.
Door Latch Adjustment
If the door latch is too tight, you can reduce the tension
on the latch so that opening the door doesn’t jar the kiln.
Please see “Door Latch Spring Adjustment,” page 22.
Firing Log Book
Record the following information in a firing log book:
1) Date
2) Firing temperature, speed, and hold; or the Ramp/Hold
3) Starting time
4) Total firing time
5) Type of pieces
6) Firing results
As you gain experience, you will find a wealth of information in your firing logs. Keeping records will give you a
“feel” for how your kiln fires and will enable you to duplicate the best results.
Low Temperature Holds
A low temperature hold (i.e. 200° - 300°F) is more difficult to maintain than higher temperature holds (1400° 1700°F). At low temperatures, turning on the heating elements affects firing temperature to a larger degree than
at high temperatures.
To hold at a low temperature, heat the kiln slowly. Otherwise the kiln temperature may overshoot the hold temperature before the heating elements cycle off.
Avoid Contaminating Heating Elements
The heating elements are embedded
into the firing chamber.
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 elements. Never fire glazed ceramic ware,
glass, or enameling directly on the firing chamber bottom. Use a ceramic shelf on short posts to protect the bottom from glaze drips, glass, and enameling powder.
Note: If a contami-
nant such as dripping glass or glaze
embeds into the firing chamber, unplug the kiln. With
the kiln at room
temperature, use a knife to gently scrape off the
contaminant, being careful not to damage the
heating element. Vacuum the kiln. (See “Ceramic Fiber Repair,”
page 23.)
The Optional Glass
View Port
Caution: Wear green #3
firing safety glasses
whenever looking into
the optional view port.
Loading the Kiln
Place Ware on a Protective Shelf
Always protect the firing chamber by firing your pieces
on a shelf or in a bowl. Do not place the pieces directly on
the bottom of the firing chamber.
Center the shelf inside the kiln. If your kiln has a glass
view port or bead door, you may need to position the shelf
farther back inside the kiln away from the door.
Caution: NEVER use a glazed bowl to hold alumina hydrate or vermiculite. If the glaze runs, it
can embed into the firing chamber.
Types of shelves and containers:
Fiber Shelf
The ceramic fiber shelf is used to support silver and
gold clay. Place ½” posts under the shelf for more uniform heat.
The ceramic fiber shelf
contains binders that burn
out during the first firing.
Do not be concerned if the
shelf becomes discolored.
It will turn white again after the kiln reaches about
1000°F / 537°C.
Note: Fire only silver or gold clay on the fiber
shelf—never ceramics, enameling or glass. Do
not coat the fiber shelf with glass separator or kiln
Fireclay Shelf
Ceramic fireclay
shelves, available from
Paragon, protect the firing chamber bottom and
provide a smooth surface. Use a ceramic shelf
to fire ceramics, glass,
and enameling. Support
delicate silver clay pieces
by pouring a mound of vermiculite or alumina hydrate
onto the fireclay shelf. Flat clay silver can be fired directly
on the shelf without further support.
Insulating Firebrick Piece
Insulating firebricks are porous, light-weight, and can
be shaped to support
delicate silver clay designs. Carve the firebrick with a knife or
hacksaw. You can also
fill the recessed area of
the brick with vermiculite or alumina hydrate.
(Vermiculite is available from garden supply stores.)
Caution: Avoid breathing alumina hydrate dust.
Caution: Alumina hydrate can destroy the heat-
ing element on contact. If it spills onto the firing
chamber, remove with a vacuum cleaner.
Ceramic Fiber Blanket
Place the blanket scrap directly on the firing chamber
bottom. Use the blanket to support delicate silver and
gold clay, but never ceramics, enameling or glass.
Applying Glass Separator or Kiln Wash
Glass and ceramics are fired on a fireclay kiln shelf and
not directly on the kiln bottom. You can also slump glass
over a mold, such as a bowl. The kiln shelf and sagging
mold must be coated with glass separator to prevent glass
or ceramic glaze from sticking to them.
Unless you fire glass to a full fuse, a coat of separator or
kiln wash will usually last through several firings. When
the shelf coating begins to crack or chip, apply a fresh
Shine a sidelight across the shelf surface or hold the
shelf vertically under a light
source. With light shining
directly across the shelf, it is
easier to see cracks and
flakes in the glass separator.
If you see imperfections, reapply the glass separator.
To recoat a shelf, first remove most of the old coating Separator lasts through several
with a small putty knife held glass firings. Apply new separator
at a 45° angle. This gives you when the old coat begins to flake.
a smooth surface to start
with. Removing glass separator creates dust and sometimes flying debris, so you should do this outside. A putty
knife will also remove ceramic glaze or glass that has
stuck to the shelf. In addition to wearing a dust mask, it is
a good idea to wear safety glasses.
Then recoat the shelf using the following directions.
(Both glass separator and kiln wash will be referred to as
Caution: Do not breathe glass separator powder.
Do not apply glass separator to the ceramic fiber
firing chamber or to the bottom of the shelf. Do
not allow glass separator to come near the embedded heating element.
Note: Do not coat the soft ceramic fiber shelf with
separator. If you are firing only silver or gold clay,
you do not need separator. When firing silver clay
with glass, however, fire the piece on a hard fireclay shelf coated with separator.
Mix the separator with water following the directions on the bag. Pour the separator carefully to
avoid creating airborne dust. (Do not breathe the
dust.) Stir.
Apply the separator to the shelf with a haik brush
or soft paint brush.
(The haik brush is
easier to use because it
lays down a more even
coating.) Each time
you dip your brush into
the separator mixture,
swirl the brush around
the bottom of the container. This is because
the separator settles
quickly. Use two or three thin coats changing the
direction of the brush stroke 90° with each coat.
Moisture in the kiln shelf can crack glass or cause
bubbles during fusing. So dry the shelf thoroughly before use. To speed drying, place the
shelf on three ½" posts inside the kiln. Heat at
full rate to 300°F/148°C and hold for five minutes. Then turn off the kiln and leave the shelf inside.
After the separator has dried and your shelf is
cool, you can smoothen the separator further by
rubbing your hand lightly over the shelf. The
smoother the separator, the smoother the back
side of the glass.
A more advanced technique for smoothening the separator is to fire the
freshly applied glass
separator to around
1000° F. After the shelf
cools inside the kiln, remove the shelf and rub
grit cloth over the glass
separator. (Grit cloth,
available from Paragon,
is an abrasive-coated
mesh that allows residue to pass through. It
can be rinsed with water and reused many times.) As you rub the glass separator, watch the brush-stroked surface. Remove just
enough glass separator to remove the brush strokes. It
takes just a few passes to smoothen the surface.
A coat of glass separator will usually last several firings.
The lower the fusing temperature, the more firings you
can get from one application of separator.
Using Ceramic Fireclay Posts
To vent the kiln, remove the top vent plug at the beginning of the firing. Do this outside or in a room that has
good ventilation. When the venting is completed, insert
the vent plug to conserve energy for the rest of the firing.
Venting will be explained in greater detail in sections on
glass and ceramics.
Looking Into a Hot Kiln
Ceramic posts are used to support ceramic shelves inside a kiln.
Place 3 - ½" ceramic posts under either the ceramic
hard fireclay shelf or the soft fiber shelf to get better air
circulation. (However, the posts are not essential. We recommend the posts, but if you don't have them, it is still
okay to fire the kiln with the shelf directly on the firing
chamber bottom.)
You can fire two or more ceramic fireclay shelves in a
Paragon jewelry kiln. Support the bottom shelf on three
½” posts. Separate the shelves with taller posts. The
length of the posts and the number of shelves you can fire
depends on the size of the kiln. When you load multiple
shelves, fire at a slower rate. This aids heat distribution.
Make sure the shelves are not too close to the walls of
the kiln. Otherwise the embedded heating element could
overfire the ware placed near the edge of the shelf. Also,
do not allow a shelf to touch the thermocouple. This will
cause an inaccurate temperature reading. A shelf should
be at least ½" from the thermocouple.
Venting the Kiln
Some types of firings, such as ceramics or lost wax
casting, produce fumes that must be vented from the
kiln. Silver and gold clay need no venting unless you are
firing them with a material that burns out to produce a
hollow shape or you are combining them with other materials such as glass.
Sometimes it is necessary to open the door of a hot
kiln. Most copper enameling is removed from the kiln at
1450°F / 787°C. You can also crack the door open for a
couple of seconds to visually check the progress of glass
fusing, especially when you are firing a particular type of
glass for the first time. (When the fusing is finished, make
a note of the temperature so that you can program future
firings. Then turn off the kiln or begin the annealing
Crack the door open about ¼” to check the progress of the
glass or enameling. It takes only a couple of seconds.
If you are removing a piece of ware from a hot kiln, first
turn off the power to the elements by pressing the kiln's
on/off switch. But if you are only cracking open the door to
look at the glass or enameling, you can leave the kiln
turned on. Opening the door will not harm the kiln.
You can also
look into the kiln
by opening the
optional bead
You should
wear heat-protective gloves and
green #3 firing
safety glasses.
Keep your face
about 15” away as you look into the hot kiln. Open the
door just a crack for a few seconds, just long enough to see
the progress of the glass. The temperature may go down slightly.
Of course an easy way to visually
check the glass is to look into the
optional glass view port.
Silver & Gold Clay
With silver clay, you can shape intricate, free-form silver jewelry in minutes—even as a beginner. (The clay is
also available in gold; for simplicity we will refer to both
metals as “silver clay.”) At the time of printing, the silver
clay brands available were Art Clay Silver and Precious
Metals Clay.
Silver clay looks and feels like modeling clay. It is
formed with simple tools such as a tooth pick, small knife,
and razor blade. Its surface is pliable and accepts impressions from objects such as leaves, coins, and coarse fabrics. After the silver clay is formed, it is fired in a kiln. The
recommended temperature and hold time are included
with the silver clay.
Forming and firing silver clay is simple. There is nothing mysterious about making silver clay jewelry. The silver clay is made of micron-size silver particles held in an
organic binder. During firing, the binder burns away.
The silver particles then fuse together forming real silver.
Since the binder disappears, the piece will shrink. The
amount of shrinkage varies depending on the type of silver clay you use.
You can also place the silver clay on a piece of ceramic
fiber blanket, especially delicate rounded or hollow
shapes that may need support to prevent collapsing.
Venting the Kiln
Silver clay by itself needs no venting. Load the kiln,
close the door, and leave it closed until the silver clay is
ready to remove.
However, the kiln needs venting if you fire ceramics or
glass with the clay silver, or if you make hollow objects
that contain a core of organic materials.
Caution: Cork clay, cereal, pasta, and bread are
good core materials. Do not use wax or styrofoam
as a core. They emit harmful fumes.
To vent the kiln, remove the top vent plug at the beginning of the firing. Do this outside or in a room that has
good ventilation. When the venting is completed, insert
the vent plug to conserve energy for the rest of the firing.
Drying Time
To be on the safe side, give the silver clay plenty of time
to dry. Otherwise pieces may warp during firing. As you
gain experience, you will know how much drying time
each type of piece needs before firing.
Note: To speed drying, use a hair dryer, or dry sil-
ver clay pieces on top of the kiln as it fires.
As a general rule, if the silver clay piece feels cool
against the inside of your wrist, it is still wet.
Loading the Kiln
Silver clay pieces that
have a flat side can be
placed inside the kiln directly onto the soft ceramic fiber shelf.
I Silver clay pieces can
be close together, but
they must not touch.
Caution: When venting materials such as cork
clay, remove the vent plug at the beginning of the
firing. Removing it later during the firing may
cause the organic materials to flame up for a moment. Should this happen, leave the door closed
so that the flames can die out safely.
Rate, Temperature, Hold
Do not coat the soft ceramic fiber
shelf with glass separator or kiln
For more uniform
heat, place ½” posts
under the soft ceramic fiber shelf.
Do not coat the ceramic fiber shelf with kiln wash or
glass separator.
If you are firing silver clay by itself on fireclay shelves,
you do not need kiln wash. But if you combine the silver clay with glass, coat the fireclay shelf with kiln wash
or glass separator.
When firing cork clay, leave the vent plug out from the
beginning until around 800 °F / 430°C. Hold for 1 hour.
After the hold, insert the plug. Keep the door closed during venting.
Each brand and type of silver clay fires at a specific rate,
temperature, and hold time. This information is available
from your silver clay supplier.
Select the heating rate that the silver clay manufacturer recommends if you are firing silver clay alone. If you
fire glass or ceramics with the silver clay, select a rate best
suited for the glass or ceramics.
You may also need a slower rate for hollow silver clay
pieces that have core fillers to burn out. If the filler is
completely enclosed, leave a small hole in the silver.
Note: Do not place hollow silver clay pieces that
have a core filler into a hot kiln. The filler could
flame up and crack the silver.
Note: It is okay to place silver clay pieces into a hot
kiln (approximately 500°F / 260°C) provided the
pieces are completely dry and do not contain
other materials such as glass or stones. (Moist
silver clay could explode or crack in a hot kiln.)
Do not insert a fireclay shelf into a hot kiln.
After the kiln begins firing, leave the door closed. Do
not open the door until it is time to remove the clay. Visual
inspection of the clay is unnecessary.
If you are firing glass with the silver clay, on the other
hand, you may need to check the fusing progress of the
Crack the door open about ¼” to check the progress of the
glass. It takes only a couple of seconds.
glass by opening the door ¼” - ½” and looking inside.
Look for just a second or two. As you gain experience, you
will be able to program the correct temperature for the
silver clay and glass combination, eliminating the need to
visually check the glass.
Cooling the Piece
After the clay silver has fired to completion, you can
crack the door an inch to speed cooling. If you are firing
stones, glass, or other materials with the silver clay, it is
safer to allow the kiln to cool slowly with door closed. Remove the piece after the kiln reaches room temperature.
Silver clay pieces that contain no other materials can be
removed from the kiln right after the hold time is over.
Remove the shelf with an enameling fork or long-handled
spatula, heat-resistant gloves, and safety glasses. (If you
remove large pieces at higher temperatures than 800°F /
430°C, the pieces may warp.)
Caution: Turn the kiln off before inserting any-
thing into the firing chamber.
Caution: Place the hot shelf onto a fireproof sur-
face such as a large ceramic shelf. Also
remember that the heat from the hot shelf can
transfer through the fireproof surface to the table
You can drop the hot silver pieces into water for fast
cooling. This is call quenching. To avoid warping, allow
the pieces to cool down to 800°F / 430°C in the kiln before
Combining Silver Clay
With Other Materials
There are two ways to fire silver clay with other materials such as glass:
I Fire the silver clay first by itself. After you have cleaned
and polished the silver clay, fire it a second time with
the other material.
Fire the silver clay and other materials, such as a stone,
together in a single firing.
Enameling powder must be fired with the silver clay in
a separate second firing. (See page 16.) Glass is often
fired with the silver clay in a single firing. Many types of
glass will melt to the point of overfire at silver clay temperatures. So before combining glass and silver clay in a single firing, test a small glass sample. To do this, fire the
glass during a silver clay firing, keeping the glass separate
from the silver clay piece. (This way you won’t ruin the
silver clay.) Place the pieces on a ceramic fireclay shelf.
Coat the shelf with glass separator, or otherwise the glass
sample may embed into the shelf.
If the glass sample survives the firing, you can fire that
type of glass with silver clay in a single firing. Note, however, that different types of glass fire to different temperatures. Every time you fire a different type of glass, be sure
to test.
Frequently Asked Silver
Clay Questions
By Sallie Bly
What is the difference between PMC and Art Clay
Both companies manufacture metal clay. They are like
Pepsi and Coke—similar but slightly different. Both
companies have clay, syringes, paste, and paper; both
have high-fire and low-fire products. However, they each
have unique products that the other does not have. If you
learn to use one company’s clay, you will be able to work
with other company’s clay. When you fire, refer to the Art
Clay Silver firing guide for Art Clay Silver and the PMC
firing guide for PMC.
How many coats does it take to coat a leaf, and why
does the leaf curl when I am painting it?
This is one of the hardest questions to answer without
being in a classroom. It depends on the size of the leaf, the
structure of the leaf’s vein, the end use of the fired leaf,
and how thick your paste is.
Your first few coats are vital to your project. The paste
should be air-dried for the first coats, because if the leaf
dries out before you get enough paste on it to weigh it
down, the leaf will curl. Even when air drying, don't let too
much time pass before adding the next coat, or again your
leaf will curl.
What happens to the leaf and other combustible
objects in the kiln?
Straws, leaves, cork clay, and other natural products we
use to support the clay burn away. Sometimes they leave
residue in the kiln. Occasionally use a small computer
vacuum cleaner or canned air to clean out the kiln interior.
If I don't like what I make, can I melt it down and sell
it for scrap?
Yes. However, I always advise my students that no matter how much they dislike something they have made in
metal clay, there is someone out there who will love it and
will pay more for it than the student would get for it as reconstituted silver. One of the designs I had to make in my
Level II class was really ugly, and I thought I made it even
uglier than it was intended. I put it up for sale at a high
price, because we all know that the biggest mistake an
artist can make is to sell something too cheap. The
woman who bought it was excited to have a one-of-a-kind
handmade silver necklace. I made a lot more than I paid
for the silver.
Can I refill the syringe with paste?
Yes, but there will be air bubbles that might ruin your
design. I keep one syringe refilled with thick paste that I
use as a filler. It is just as good as my sludge pot.
The silver clay shown in magazines sometimes is
shiny, sometimes has a matte look, and sometimes it
is colored. Do all of these come from the same clay,
and how do they get the colors?
The silver finish is determined by how you work with
the clay both before and after firing. A high shine is
achieved with sandpaper, rotary drill using 3M radial
bristle discs, magnetic burnishers, or just good old-fashioned elbow grease.
Most people think that Liver of Sulphur gives silver an
old, black effect. Wrong. When used correctly, you can get
the color and effect you want: gold, amber, magenta, blue,
and then black. Most colored pieces are made with Liver
of Sulphur or enameling.
Can I fire the clay with sterling silver findings?
The new low-fire clays (650 for Art Clay Silver and
PMC3 for PMC) mix well with sterling silver. I have had
only one case where they were incompatible. I now always
test sterling silver findings or sterling silver wire with a
little metal clay on it in the kiln first. If there is no reaction,
I continue with the project.
If a piece breaks after firing, can it be soldered?
Yes. However, Art Clay Silver has a product called Oil
Paste that works with pieces that have been fired and burnished. It is like soldering in the kiln, and it is easy.
I have read that gemstones can be fired directly into
the clay. Can I fire my diamond in it?
Most CZs can be fired into your projects. I have seen
several failures with stones that were supposedly tested
for the heat required for the metal clays. One beautiful diamond-like CZ became cloudy and had an opal appearance—very attractive and fortunately it worked with the
design, but a failure nevertheless.
One CZ lost all of its facets and became a rounded
piece of glass. This was a real failure, and I had no solution for fixing it.
In my studio, I test all stones personally before they are
worked into projects. If a stone fires correctly the first
time, it will fire the same way (at the same temperature)
in each subsequent firing.
As for your diamond, the answer is no. However, you
can place a setting into your piece and set your diamond in
after the firing.
Can I enamel on the metal clays?
Yes. You might have read that it is not recommended
to enamel on sterling. There again, it is the alloys that
cause the problems.
How long is the clay good for? What do I do if I open
the package and it is dried out?
The clay is good indefinitely. Until it is fired, it can be
reconstituted and reworked into something else.
I had a 20-gram piece that I wasn't happy with. I kept
thinking that if I just added one more thing here and
there, it would be great. Eighty grams and one year later, it
was time to give it up. Because it sat on a bureau in a hot
dry room for a full year and because it was so big, it took a
week to reconstitute. The piece I made with that reconstituted 80 grams is one of my favorites.
After a student works hard on their first piece, they
often say, "I don't like this. Do I have to fire it?"
Yes. There is a big difference between what your piece
looks like when it is still in the clay stage and what it looks
like after it is fired. I always tell my students that it is imperative that they fire their first pieces. I guarantee that if
they do not like it, I will exchange it for the same amount
of silver clay. I have never had a student take me up on it.
However, once students can tell from experience what
the finished piece will look like, I back up their decision to
reconstitute the clay and start over.
How much does the clay shrink?
The clay will shrink approximately 10 percent. PMC
makes a ruler that allows you to create your piece taking
that shrinkage into account.
Can I really make metal clay jewelry if I am not an
I strongly believe that inside everyone is an artist just
waiting to be discovered. I have had students that had
never done anything “crafty” before taking my class. A lot
of them go on to sell their work starting with friends and
co-workers, and some have become affiliated with a gallery. You do not have to believe in your talent to learn, but
learning and doing will help you to believe in yourself and
your talent.
Glass Fusing &
You will probably fire mostly stained glass, but you can
also fire standard float (window) glass. Some types of float
glass devitrify (form a dull, frosty surface) when fired.
Caution: Never fire tempered glass. It could explode if heated inside a kiln.
Basic Glass Tools
uses a reservoir of oil to
lubricate the cutter wheel.
are for cutting large pieces of glass.
are for cutting small strips.
shape the glass by chipping away the
edges. They are often used when the score line doesn’t
break cleanly. Note that rough edges will become smooth
when fired to fusing temperature.
How to Cut Glass
Note: IMPORTANT! Wear safety glasses when
cutting or chipping glass.
Lay the glass on a clean surface. Mark off the cut
with a grease pencil or felt-tip pen. A small mark
on each end of the glass will do. Lay a wooden
straight edge over the glass and line it up with the
marks you just made.
Hold the straight edge firmly and score the glass
with the glass cutter. Press just hard enough so
that the scoring noise sounds steady and unbroken.
Place the straight edge under the glass so that an
edge is lined up with the score line you just made.
Press down on the glass. It will break cleanly.
Fusing Compatibility
of Glass
When glass changes temperature, it expands and contracts. The rate at which glass changes size is called the
coefficient of thermal expansion. If you fuse two glass
pieces together and one changes size faster or slower
than the other, the fused piece may crack—even several
months after fusing.
When different glasses have a close enough coefficient
of expansion to fuse successfully, they’re called fusing
compatible. Buy glass labeled fusing compatible. Or fuse
glass that has been cut from the same sheet, which guarantees compatibility.
Fusing glass is rated with a coefficient of expansion
number (i.e. COE 90 or COE 96). The pieces that you
fuse together should have the same COE number. Carefully label glass storage containers with the COE number
to avoid mixing different types of glass.
Fusing Compatibility Test
To test glass for compatibility, fuse small ½”
square sample pieces of different glasses onto a
larger base piece of clear transparent. It should extend beyond the small sample pieces by half an
inch on each side. One of the sample pieces should
be cut from the base piece.
With polarizing filters, you can test the compatibility of glass. Photo courtesy of Bullseye Glass Co.
Heat the glass to a temperature that completely
rounds the edges of the small sample pieces.
After the glass cools, place a polarizing filter under the glass and another filter over the glass.
Look at the glass with light shining through it
(hold it over a lamp). Turn one of the filters until
the filters are at their darkest. (Polarizing sheets
are available from Edmund Scientific and photo
supply stores.)
Results of the Test
If you see a halo around the edges of the small glass
samples, this usually means the glass is not compatible. If
you see no halo, the glass is fusing compatible.
Why did we include a sample square cut from the base
transparent glass? It tests for annealing. A halo around
that piece means the glass was not annealed properly.
Perform the test again, this time cooling more slowly
through the annealing range.
The Annealing Range
Each type of glass has a temperature range that it must
pass through slowly when it cools. This is called the annealing range. This slow cooling gives hot glass time to
release the stress of cooling. If you cool the glass too fast
through the annealing range, it will break.
The larger and thicker the glass, the slower it must
pass through its annealing range. You cannot over-anneal, so err on the side of caution if you aren’t sure how
long to anneal. Small projects such as earrings rarely need
annealing time as they cool.
out of place before they fuse. The glue disappears during
Avoid using glue on the coated side of dichroic glass. If
you lay dichroic glass carefully onto the piece, glue is unnecessary, so avoid it altogether if you do not know which
side of the dichroic is coated.
Loading the Kiln
Air should circulate between the fireclay shelf and the bottom of the kiln, so
place three or four ½”
posts under the shelf.
You can fire two
shelves of glass in the
kiln. However, one
shelf will be tack
fused and the other full fused.
Firing the Glass
Vent the kiln by leaving the vent hole open.
Venting allows gases to escape. When the kiln
reaches 500 - 800° F / 260 - 426°C, insert the plug.
Cleaning and
Gluing the Glass
Grease, dirt, and fingerprints etch permanently into
the glass during firing. Clean the glass with glass cleaner
(the type without silicones), rubbing alcohol, or even plain
water just before assembling the pieces
on the kiln shelf.
Use white glue,
such as Elmer’s diluted 1:1 with water,
to hold the glass
pieces together after
you place them on
the kiln shelf. Use
the glue sparingly.
Glue is especially
important when fusing wire into the
glass. The glue prevents the glass or
wire from moving
The first time you fire a particular brand or type
of glass, program the controller for a higher temperature than the estimated fusing temperature.
Watch the glass by opening the door ½” for several seconds at a time. Shut the kiln off when the
Looking at the glass during firing. Open the door about ½”. Always
wear green #3 firing safety glasses when looking at the hot glass.
glass fuses the way you want. Make a note of the
shut-off temperature. For future firings, program
the kiln for that temperature and rate.
Note: With every firing, be sure you are near the
kiln before the expected shut-off time.
After you shut the kiln off, vent the kiln for 5 minutes by opening the door 1”. Then close the door.
Note: Some glass artists flash cool the glass after
it fuses. They vent the kiln as above until the temperature drops to 1000° F. Then they close the
door. This speeds up cooling.
The annealing range for most glasses is between
950°/510°C and 700°F/371°C. Cool slowly through
this annealing range. Leaving the door closed will
slow the cooling enough for most projects. If you
need even slower cooling, program a separate segment for cooling. See the kiln’s digital controller
Note: For safest cooling, leave the ware inside the
kiln until the kiln reaches room temperature. If
you remove the ware too soon, the sudden temperature change can crack the piece.
To remove small
pieces, such as glass
jewelry, before they
have cooled completely, remove the
shelf also. Leave the
pieces on the shelf
until they reach
room temperature.
The heat in the
shelf will help prevent them from cooling too
Caution: Before removing a
shelf, turn off power to the
Glass Beads
Glass is sensitive to breakage as it cools through the
annealing range. This is approximately 950°F/510°C
through 700°F/371°C. The larger the piece, the slower it
must cool.
To safely cool flame-worked glass beads, anneal them
in your kiln using the bead door. If you are interrupted
while making a bead, you can place the mandrel in the
kiln until you are ready to resume working.
Program the controller in Ramp-Hold for the following two segments. (See the separate digital controller
manual.) If your bead-making session will be longer than
3 hours, program a longer hold time in segment 1.
1799°F / 999°C
100°F / 222°C
700°F / 371°C
Fire the kiln. When it reaches 1000°F/537°C, it will
maintain that temperature for three hours.
Annealing the Beads
At 1000°F/537°C, the kiln is ready to receive the
bead mandrels loaded with hot beads.
Note: Allow freshly finished beads to cool slightly
before inserting. This is to prevent the beads
from flattening on one side when they are placed
inside the kiln. You can place the beads directly
onto the floor of the kiln provided they have
cooled slightly as described above.
Open the bead door. Insert the mandrels as you
complete the beads. Leave the door ajar with the
end of the bead mandrel extending outside the kiln.
Shown is a hair barrette glass sagging
mold. Sag the glass over the mold, and
glue the glass to the barrette. Sagging
molds are also available for glass
When you have finished the
batch of beads, perform a
Skip Segment. This will end
the temperature hold and begin segment 2. The kiln will
slowly cool through the annealing range.
After the kiln shuts off, leave
the beads in place. Do not remove
them until the kiln has reached
room temperature.
on Metal
Preparing the Copper
Enamels come in transparent or opaque. They can be
purchased directly from Thompson Enamel, P.O. Box
310, Newport, Kentucky 41072. Their lead-free enamels
come ready to use—no enamel washing is required.
Start with one of the many pre-shaped copper forms
available, or shape and trim the copper to your own design.
Heat the copper on an enameling rack to about
1400°F/760°C to burn off oil or grease. Heat the
copper to just until smoke from oil or grease
stops coming off the metal and its color has
changed to a purple-red-pale green iridescence
that moves across the copper. This indicates that
the grease has vaporized.
Otherwise excess fire
scale will form, making the next cleaning step
After the copper cools, brush any loose scale from
the copper. Use a brush or paper towel, being
Decorating the Copper
Counter Enameling
Most enameled pieces should be counter enameled on
the back side. This gives the piece a much more finished
look, it eliminates a great deal of fire-scale cleaning, and it
controls the chipping and cracking that can result from
the different rates of expansion and contraction in copper
and enamel after the enamel has been fired.
Counter or backing enamel, a mixture that gives a
mottled effect, can be used for counter enameling. Or you
can use regular enamel. Counter enamel is applied by the
sifting method described below.
When firing counter enamel, underfire it so that the
fire scale on the front of the piece isn’t too difficult to remove. You can purchase a masking preparation from your
supplier to help prevent fire scale. You must place the
piece on a stilt when firing the other (front) side of the
piece. The stilt prevents the back of the counter enameled piece from sticking to the enameling rack.
Applying Enamels
sure that you do not put grease or oil onto the
copper, such as fingerprints. Clean the copper
with a 3M Scotch-Brite® pad. This pad does
such a good job that in most cases no further
cleaning will be required. Additional copper
cleaning products are available in the Thompson
Enamel catalog, including Sparex No. 2.
It is best to clean the copper just before you decorate it.
If you wait too long to decorate after cleaning, the copper
could get dirty again.
Apply enamel over a clean sheet of paper so you can
pour the excess back into the bottle for reuse. Transparent enamels should be applied in several thin coats.
Transparent enamels can be mixed with fairly good results. If opaque enamels are mixed, however, a grainy effect results. The two basic methods of applying enamels
are sifting and spatula.
Sifting Enamel
Spray or brush Thompson holding agent onto the copper. Then sift a 1/32” layer of enamel onto the copper.
Use a #60 mesh sifter. If the coat is too thin, you can easily add another coat after firing. But a coat that is too thick
will bubble and crack. The enamel must dry completely
before firing.
Spatula or Inlaid Method
You can use this method to decorate a small area with
many different colors. Using a diluted solution of
Thompson holding agent, dampen the enamels just to
the saturation point, and maintain this moisture while
working with the enamels. Apply the enamels onto the
copper with a small spatula, and spread them out with a
spreader to a coat of about 1/32” thick. Lines of contact
can be formed by the spatula blade. Then spray the
enamels with the holding agent to keep the grains of
enamel in place. Allow the enamel to dry completely before firing.
Firing Enamel
Heat the kiln to 1450°F/787°C for most enameling.
Use a single segment. (Please see your digital controller instruction manual.)
Note: Hold time should be the length of time you
will be inserting enameling into the kiln. In the
above example, hold time is 1 hour.
Lay the copper shape on an enameling rack. If the
part that touches the rack is enameled, place a stilt
under the copper. Some bowls or other shapes
have enameled sides that might run during firing.
These should be fired with a stilt even if the piece
has a plain bottom. Use an enameling fork or a
long spatula to place the rack into the kiln on top of
½” ceramic posts.
Note: Firing the piece at enameling temperature
should take about 3 minutes and requires undivided attention!
Look at your piece every 15 seconds by cracking
open the door. Remove the rack when the copper
piece appears a rosy red and the enamel is smooth.
Place the rack on a steel pad or large ceramic kiln
shelf and let it cool completely.
After you remove the enameling piece, allow the
kiln to heat up again to the enameling temperature. Then insert the next enameling piece.
Ceramic Overglaze
and Decals
Pyrometric cones are
small pyramids of clay and
mineral oxide that soften
and bend when exposed to
heat. They indicate when
ceramic ware has fired to
cone fired to matuPyrometric cones come Arity.self-supporting
Do not be concerned if the tip is
in 1 1/8" and 2 ½" lengths. slightly higher or lower than shown.
Use the 2½” cones. Cones
mounted on the kiln shelf
must be slanted 8° from
vertical. They will not
bend accurately if they are
slanted to the wrong angle. Self-supporting large
cones have the correct
slant built into the base.
Standard cones must be
mounted in a clay or wire
A “puddled” over-fired cone.
The chart on page 18
shows the temperatures
of pyrometric cones. Program your controller to
the cone recommended
for the ceramic ware that
you are firing.
For small ceramic
pieces, such as figurines,
program a rate of
400°F/222°C. Fire to the Under-fired cone.
temperature shown in the
108°F column of the
Temperature Equivalents chart for the cone number you
are firing.
Before deciding on the firing speed of important
pieces, test fire sample clay pieces.
Note: Do not fire beyond your kiln’s maximum
temperature. Firing hotter will void your warranty. Kilns with glass view port: Do not fire hotter than 1700°F/926°C.
After counter enameling, you will need to clean the
fire scale off the front of the piece. A 3M Scotch
Brite® pad works well for this. Then clean it with
Thompson Sparex No. 2.
Loading and Firing
Overglaze is decoration applied over fired glaze or polished porcelain bisque. Overglazes include china paints,
gold, and luster, which fire from cone 022 to 014.
Note: You will need to buy the porcelain plates,
cups, etc. that you use as blanks for the overglaze.
The initial firing of a porcelain blank is beyond
the temperature range of your Paragon jewelry
Load overglazed ware the same way you would load ceramic glaze. Use stilts and make sure ware is not touching other ware. Ware must be completely dry before firing.
Ceramic tiles are one
of the most popular
overglaze projects for a
small kiln. Use a tile
holder to fire several at a
China paints will
crack or peel if applied
heavily. Apply several
light coats instead, firing between each, until you get the
shade you want. Not all china paint colors reach maximum color saturation at the same temperature even
when fired on the same ware. So you must know which
colors you should fire first at higher temperatures to prevent burning out the original colors in later firings. For
example, reds mature at a lower temperature than other
colors and are fired after the other colors have been fired.
Reds and yellows should not be fired side by side. Colors
also mature at a lower temperature on ceramic pieces
than on porcelain or hard china. Check the overglaze
manufacturer’s literature for information on which cone
to use with each color and type of ware.
Vent the kiln during the first hour of firing, or until all
smoke disappears. Allow the kiln to cool to room temperature before opening the door.
Cut out the decal and soak in lukewarm water until you can slide the image from the paper backing onto the ware. Slide the image off the backing
rather than attempting to lift the image off.
Position the decal on the ceramic or glass piece.
The side of the decal that was up on the paper is
the same side that goes up on the ceramic or
Use a damp sponge or rubber squeegee to
squeeze out air bubbles and water from the decal. For flat surfaces, use a rubber squeegee; for
curved surfaces, use a damp sponge.
Dry the ceramic or glass piece overnight before
Fire a glazed ceramic blank on a stilt placed on
top of a fireclay shelf. Glazed pieces must not
touch each other. Fire glass directly on a fireclay
shelf. The shelf must be coated with kiln wash or
glass separator.
Fire in a well ventilated area. Keep the top vent
plug out during the first hour or until the smoke
and odor disappear.
Fire at a rate of 500°F / 275°C to the recommended temperature for the decal you purchased. Most decals fire to cone 015 - 018. Use
the Orton cone chart to convert the cone number
to a temperature.
After the kiln shuts off, leave the door closed until
the kiln cools down to room temperature.
Temperature Equivalents For Orton
Self-Supporting Pyrometric Cones
Heated at:
Fire decals onto glazed ceramic cups, tiles, light
switches, photo frames, and much more.
Don’t worry if you ruin the first few decals. Applying
them takes practice. Before starting, clean the ceramic or
glass piece with water.
27° F
108° F
270° F
Per Hour* Per Hour* Per Hour*
Ceramic or Glass Decals
Self-Supporting Cones
Light Blue
*Rate of temperature increase during last 90 120 minutes of firing. Tables by courtesy of the Edward Orton, Jr. Ceramic Foundation.
Lost Wax Burnout
Caution: Only kilns with vent holes are designed
for lost wax burnout. However, you can use a kiln
without the vent hole provided that you open the
door ½” during venting.
Caution: Always use a wax tray.
Caution: If your kiln’s heating element is embed-
ded in the floor of the firing chamber, place the
metal wax tray on 3 or 4 - ½” posts inside the kiln.
This prevents the element from possibly shorting out against the tray.
Note: These instructions apply to injection wax
that melts at 200°F / 93°C, not pattern waxes and
plastics that melt at higher temperatures. If
smoke appears during wax elimination, turn off
the kiln. Smoking wax means the kiln fired hotter
than 300°/148°C.
Lost wax casting is the process of carving a shape in
wax , and then casting that shape in metal. After the wax
has been carved, a mold is made of the wax shape. The
mold is a negative image of the wax. The wax is later
melted out of the mold through hollow channels called
Lost wax burnout is the process of preparing a casting
mold for the melted metal that will be poured into it. The
steps in lost wax burnout:
Melt the wax from the mold.
Remove wax from the kiln before raising the temperature higher than 300°F/148°C.
Harden the mold at high temperature.
Maintain the mold at the casting temperature recommended for the type of metal that will be
poured into the mold.
Caution: Prevent wax or carbon from contacting
the kiln’s walls and elements. Carbon build-up
inside a kiln ruins the interior. Carbon conducts
electricity and causes elements to short circuit.
Damage to elements from contact with foreign
materials is not covered by warranty.
A Sample Program
(See your digital controller instruction manual.)
Segment 1 heats the wax to 300°F/148°C and holds it
for 1 hour, allowing it to drip from the mold.
Segment 2 hardens the mold.
Segment 3 lowers temperature to 800°F/426°C, the
typical casting temperature for silver. (Most types of gold
cast at 900°F/482°C.)
Note: Casting temperature depends on the size
of the mold. The temperatures shown above are
only a guide. See your jewelry supply dealer for
temperature recommendations.
Burnout Instructions
Place a metal tray inside the kiln on three ½” posts.
Place the mold on the tray’s wire mesh screen.
The mold’s sprue hole
should be down. The tray will
catch melting wax as it drips
from the sprue hole.
The wax tray includes a re-
Keep the kiln’s vent hole(s), if movable wire mesh.
any, open during wax elimination. If the kiln has no vent hole, leave the door
open ½”. This allows fumes to escape from the
kiln. Heat the kiln to 300°F/148°C and hold it at
that temperature for at least 1 hour.
Note: Do NOT heat the wax above 300°F/148°C.
Hold at 300°F/148°C for at least 1 hour. During
this hour, the wax will melt from the mold and
drip into the tray. If the kiln gets hotter than
300°F/148°C, the wax may smoke and deposit
carbon inside your kiln, causing damage.
After 1 hour at 300°F/148°C, open the kiln. Remove
the mold and wax tray. Pour the wax from the tray
and leave the tray out of the kiln until your next wax
elimination. (Do not leave the tray in the kiln!)
Heat the mold to the temperature recommended
by your jewelery supply house where you purchased the mold material. This is usually around
Lower the temperature to the casting temperature
of the metal. Hold at that temperature until you are
ready to begin casting. Remove the mold with
tongs. Wear protective gloves and safety glasses.
Saving a Carbon-Damaged Kiln
If you follow the above directions, your kiln should be
safe from wax damage. In some cases, a small amount of
carbon may form on the walls over a period of time. This
is due to the burning of wax residue that was left in the
mold. For this reason we recommend that you periodically fire the kiln to 1500°F/815°C as follows:
Open the vent cover or leave the door ajar ½”.
Fire the kiln empty to 1500°F/815°C at a rate of
300°F/166°C with a 1 hour hold (01.00).
Firing Mistakes
Silver Clay
Cracks, Bumps
Cracks and bumps that appear in fired silver clay may
be due to too much water in the silver clay before it was
fired. Dry the clay thoroughly. Another cause of cracks is
careless handling of a dried, unfired piece. To repair, fill
the crack with silver clay and fire again.
Use a slower firing rate especially if the pieces are hollow. Dry the cork clay completely before firing.
Core materials such as cork clay need venting. Otherwise the core can overheat at higher temperatures and
damage the piece. Leave the vent plug out at the beginning. After a 1 hour hold at 800°F / 430°C, insert the vent
Silver clay will not reach full strength if underfired.
You may be able to save the piece by firing again to the
correct temperature and hold. Try firing the kiln 25°F /
14°C hotter or lengthening the hold time.
Too Much Shrinkage
When silver clay is overfired, it shrinks too much and
loses detail. If the kiln is firing hotter than the temperature programmed, check the position of the thermocouple (see “Temperature is Inaccurate,” page 21). Replace
the thermocouple if it is old.
Probable Causes:
Heating the kiln too fast
Cooling the kiln too fast
Fusing incompatible glass
Glass Bubbles
Probable Causes:
Heating the kiln too fast
Air trapped between layers of glass
Grease or dirt between layers of glass
Uneven glass volume
Moisture or trapped air between the glass and shelf
Make sure the shelf is completely dry before firing. If
you have applied fresh glass separator, leave the shelf in
the kiln at 300°F/148°C for 20 minutes before placing
glass on it.
One way to eliminate bubbles is to hold the temperature at 100°F/55°C below fusing temperature for 15 minutes. This gives the shelf time to heat up to match the
temperature of the glass.
Glass Devitrification (Frosty Surface)
Glass Cracking
Not enough glass
separator on the
Most problems in
fusing are caused by
rushing the firing.
The glass must
change temperature
slowly during the critical temperature
range of 100° - 500° F /
37° - 260°C. This critical range applies to
both heating and
The second critical temperature range is annealing,
which is the cooling range of 950° - 700° F / 510° - 371°C
average. Cool the glass slowly during this range so the
stress in the glass will have time to dissipate.
If you become impatient after the glass has fused and
you crack open the door of the kiln for a few seconds to
peek inside, you may hear a “ping,” which is the sound of
glass cracking. Avoid the temptation to open the door.
Wait until the kiln has cooled to room temperature. Some
artists schedule their fusing so that it is completed before
they go to bed. That way they will be asleep while the glass
cools and they won’t be tempted to open the door.
After each firing, examine the shelf. Recoat if the kiln
wash is chipped. Glass cracks when it sticks to a bare section of shelf.
Probable Causes:
Impurities in glass
Kiln not vented long enough during initial heating
Devitrification is a frosty surface on the glass caused by
impurities. With some glasses, it is unavoidable. To
lessen devitrification, vent the door of the kiln slightly after fusing is completed. Close the door when the glass
reaches 1000°F/537°C.
Glass Separator Sticks To Glass
Probable Causes:
Firing too hot
Overglaze on the back of the piece
Instead of firing to a full fuse temperature, try firing
50°F/28°C cooler and holding at that temperature for several minutes.
Flaking glass separator can cause the
glass to crack. This is because the glass
sticks to the shelf.
Ceramic Overglaze
Breaking in Overglaze Firing
Can be caused by poorly fired bisque. A slow bisque
fire is always better for ware that is to be china painted.
The greenware should be completely dry before being
placed in the kiln.
Purple Spots in Gold
Usually due to a thin application of gold or too much
thinner. If gold is applied accidentally to an area it will
show purple after being fired unless cleaned with a good
gold remover.
Kiln Maintenance
Trouble Shooter
See the digital controller manual for additional troubleshooting information.
Circuit Breaker Trips
If the circuit
breaker trips after
the kiln has fired
for awhile, make
sure no other appliances are operating on the same
circuit as the kiln.
If the circuit
breaker trips immediately after the
kiln is turned on,
the kiln may have a
short circuit. Unplug the kiln. Remove the bottom
cover and look for a loose wire touching the case.
Broken Lines in Gold
Can be caused by overfiring or too heavy an application. However, this can be very attractive when gold is
crackled over a dark color of fired glaze.
Peeling China Paint
Can be caused by applying the paint too heavily.
Loss of Color in China Paints
Usually a result of overfiring or thinning your paint
with too much medium when applying.
Faded Colors in Overglaze Decals
This is the result of either underfiring or overfiring. If
pinks and reds are drab, refire to a hotter cone. When
used with a china paint background, apply and fire the decals first, then china paint and fire again. Check the recommendations of decal supplier. If decal was underfired,
refire to proper firing cone. If decal was overfired, the design may be repainted in china paints and refired.
Temperature is Inaccurate
Weakening of Luster Colors
This can be caused by overfiring.
White Spots in Lusters or Metals
Can be caused by moisture on the ware before it was
placed in the kiln or from having been fired at the same
time as other overglazes.
This can be caused by too heavy an application.
Make sure the thermocouple is pushed ½” - ¾” into
the firing chamber.
If the thermocouple is pushed into the firing chamber,
and the temperature is inaccurate, replace the thermocouple.
Temperature is Uneven
Make sure the shelves are not too close to the walls of
the kiln. Otherwise the embedded heating element
could overfire ware placed on the edge of the shelf.
This is because the heating element is in the sides and
back of the kiln.
Fire at a slower rate. This will give the temperature
more time to become even.
Is the door opening during firing? If so, see “Adjusting
a Door That Won’t Stay Shut,” page 23.
Raise or lower the shelf.
Bare Spots in Decals
Water or air bubbles under the decal cause bare spots.
This is due to poor contact between the decal and the
ware. All the water must be squeezed out from under the
Note: Apply lusters only on a dry day.
Powdering of Luster Colors
Do not allow a shelf
to touch the thermocouple. This will
cause an inaccurate
temperature reading. A shelf should be
at least ½" from the
After the venting period, remember to insert the vent
plug. That may improve temperature uniformity.
The area just inside the optional bead door and view
port is slightly cooler than the rest of the firing chamber. Move pieces away from the door, or change the
level of the shelf.
Changing the Door
These instructions are for installing an optional door.
Place the kiln on its back.
Remove the screws that attach the hinge to the
old door. Lift out the door.
Close the new
door all the way.
Place the female
latch on the door
so it is aligned
with the male
latch on the kiln.
Mark and drill
holes. Install
Kiln Repairs
Door Latch Spring Adjustment
Adjust the two screws on
the door latch to change the
spring tension.
Note: Do not loosen the
screws too far, or they
will fall out.
Place the new door on the kiln with the door
aligned against the hinge. Position the door so
that it is centered between the top and bottom of
the firing chamber.
Pressing the hinge
against the door,
mark the first
hinge screw hole.
Drill the hole with
a 1/8” bit, and install the screw.
Mark and drill the
other hinge screw
holes. Install the
It may be necessary to sand the
door. Sand only
the lip of the inner
door surface. Do
not sand the firing
chamber. Remove
the least amount
of door fiber
needed to make
the door fit.
You can reduce the tension on the latch even more
so that opening the door
doesn’t jar the kiln:
Remove the top screw
from the latch.
Use a toothpick or a
small magnetic screwdriver to lift out the
spring located under
the screw. Save the
Reinstall the top latch
Removing the spring
eliminates half the pressure
on the door latch. The door
is easier to open and close yet still has enough spring
pressure to stay closed.
Adjusting a Door That Won’t Stay Shut
To repair a door that pops open during firing, first adjust the door latch spring (see above). If the door still pops
open, insert a
shim as shown
Remove the
two screws
that attach
the door
latch to the
kiln body.
ing element is located where you are scraping,
avoid touching the element.
Use a vacuum cleaner to remove the dust from the
damaged area of the firing chamber. Be sure to remove all the contaminant. Otherwise it will melt
and embed deeper into the firing chamber the
next time you fire the kiln.
Caution: Keep the vacuum cleaner nozzle at least
Insert a door latch
shim under the
latch. (The shim is
available from Paragon.)
2” away from the thermocouple and the controller. This is to avoid damage to the controller from
static electricity.
Squeeze Pyrolite into the gouge. Smooth the
Pyrolite with a small putty knife.
Install the screws
that you removed in
Step 1.
Ceramic Fiber Repair
If glass, ceramic glaze, or other materials drip onto the
firing chamber, repair before the next firing. Otherwise
the glaze will remelt and embed deeper into the fiber.
Minor Ceramic Fiber Repairs
Unplug the kiln.
Cut or scrape the ceramic fiber to remove
the contaminant. Remove as little fiber as
possible. If a heating element is located where
you are scraping, avoid
touching the element.
Use a vacuum cleaner to remove the dust from the
damaged area of the firing chamber. Be sure to remove all the contaminant. Otherwise it will melt
and embed deeper into the firing chamber the
next time you fire the kiln.
Minor gouges or scrapes in the firing chamber need no
further repair. They are cosmetic and do not affect the
firing of your kiln.
Larger Ceramic Fiber Repairs
Unplug the kiln.
Cut or scrape
the ceramic fiber to remove
glass, ceramic
glaze, or other
melted contaminant. Remove as little
fiber as possible. If a heat-
Allow to dry completely before firing the kiln.
Cleaning or Replacing the
Glass View Port
To remove the window:
Place the kiln on its
Remove the two thermocouple wires (a red and a
yellow) from the back of the controller. They are
held in place by button connectors. Press down
on the button connectors and pull the wires out.
Remove the screws
holding the glass
Remove the glass.
Clean with glass
cleaner. To remove
scratches, take the
glass to an eye glass
Remove the back cover of the kiln, but do not disconnect the wires on the back cover.
Replacing the Thermocouple
The thermocouple is located in the back of the
firing chamber, held in place by a metal band.
Remove the thermocouple from the kiln.
Unplug the kiln.
Remove the 4 screws holding the controller to the
front of the kiln. Carefully remove the controller.
Removing the thermocouple.
Replacing a Relay or Transformer
Bend the new thermocouple between
porcelain insulators. The thermocouple end should
be two insulators
long after bending.
Unplug the kiln.
Place the kiln on its back.
Remove the screws holding the sheet metal bottom to the kiln. Tilt the bottom forward to gain access to the transformer and relay.
The band must secure the thermocouple. Otherwise the kiln might overfire.
Note: Do not let the thermo-
couple wires cross where
they come out of the muffle.
The wires should be parallel.
Push the new thermocouple into the hole in the
firing chamber. The twisted end must extend into
the firing chamber by ½” - ¾”. Make sure the
band holds the thermocouple. Otherwise, the
thermocouple can be pushed out, resulting in an
Caution: The ceramic insulators are designed to
separate the two thermocouple wires inside the
thermocouple hole and behind the firing
chamber. If bare thermocouple wires touch inside the hole or outside the firing chamber, the
kiln may overfire.
Thread the thermocouple wires down to the controller opening at the front of the kiln. Keep the
thermocouple wires away from electrical components and other wires.
Strip ½” of insulation from the ends of the thermocouple wires.
Hold the new part next to the one you are replacing, aligned in the same direction. Remove and
transfer one wire at a time from the old part to the
new one. Make sure each connection is tight.
Attach the wires to the back of the controller. One
wire is yellow, the other red. Make sure the wires
connect to the correct color-coded terminals.
Install the controller and back cover of the kiln.
Place the new part next to the old one, aligned in the same direction. Remove and replace one wire at a time. In the photo, the relay is being replaced. The transformer is the part in the foreground.
Replace push-on
connectors and
wires damaged by
heat from a
burned terminal.
If wire connectors
do not fit snugly
on terminals,
gently squeeze
the end of the
connector with pliers.
Caution: Push-on connectors that have been
over-heated lose their spring tension. This results in a loose connection that can cause new
components to burn out prematurely.
As you move the sheet metal bottom back into
place, make sure the thermocouple wire attached
to the back of the board is away from the other
Install the screws holding the bottom to the kiln.
Replacing the Temperature Controller
Unplug kiln.
Remove the 4 corner screws holding the controller faceplate to the switch box. Carefully lift out
the faceplate.
Disconnect the wires from the back of the board.
You will find 2 plugs and 2 thermocouple wires.
Connect the wires to the new board. Be sure to
observe color coding when you install the 2 thermocouple wires.
Reinstall the controller onto the front of the kiln.
Testing the Heating Element
When an element burns out, the ceramic fiber firing
chamber must be replaced. (Unless the element burned
out at the element connector. See the next page.)
To test for a burned out element, you will need an
ohmmeter, which you can purchase from a hardware
store or home improvement center.
Unplug the kiln.
Remove the back of the kiln. Look at the element
Each element in your kiln has
two element connectors. The
kiln shown at right has only one
element. Most SC-series kilns
have two elements, which are
mounted in the left and right
sides of the firing chamber. The
kiln shown below has two elements. The connectors for each
element are aligned vertically.
If your kiln has two elements wired in parallel, you will
see two wires going to some of the element connectors.
Disconnect the two wires from one of the element connectors to test each element. (If you leave the wires attached, you cannot test each element one at a time, because the ohmmeter will read the resistance of both
Use a ¼” nut
driver to remove
the connector
from the element
end and the lead
If the element end is too short to attach a new connector, gently dig out the ceramic fiber with a
screwdriver to expose more element. Remove as
little ceramic fiber as possible.
Shown here is a 120 volt SC-2 kiln that has two elements wired in parallel.
Note that the two wires have been disconnected from the upper right element connector before testing with an ohmmeter.
Place ohmmeter leads against the element connectors of each element, one at a time. A no-needle-movement reading on an analog meter, or
OPEN on a digital meter, indicates a burned out
Note: Be sure the battery in your ohmmeter is
good before assuming that you need to replace
the firing chamber.
We have produced a video showing how to replace the
firing chamber muffle. Go to and
click on Support from the main menu. Then select
Support Videos from the drop menu. Look for video
M028. You can also return the kiln to the factory for
Sandpaper the eyelet of the element lead wire until
bright and clean of all oxidation. Use the brass
screw to connect the lead wire eyelet to the new element connector. Before tightening the screw, adjust the eyelet to where it will be tilted away from
the firing chamber when the connector is attached
to the element. Then hold the connector with
locking pliers and tighten the brass screw securely
with a ¼” nut driver.
Use the stainless screw in the element connector
to hold the element. (The brass screw holds the
element lead wire eyelet.) Hold the connector with
locking pliers as you tighten the screw with the ¼”
nutdriver. Tighten the screw to 30 inch pounds
(about 1 ¼ turns past the point of firm resistance).
The element connector must be tight!
Repairing an Element Connector
Sometimes an element fails due to a
burned out element connector. To check the
connectors, unplug the
kiln and open the back. A
burned out connector
will be loose or disconnected from the end of
the element. Order a
new connector from Paragon.
You will see the element connectors
after you lower the kiln’s back panel.
Install the back cover of the kiln, arranging the
wires so that they do not touch an element connector when the cover is in place.
Paragon Kiln
Limited Warranty
Paragon kilns are warranted to the original purchaser
by Paragon Industries, L.P. (herein “Paragon”), subject
to the listed exclusions below, to be free of defects in
workmanship for the periods specified below. The warranty period begins from date of shipment from the Paragon factory unless date of original purchase from an authorized Paragon distributor or dealer can be established.
Warranty Period: J-series, SC-series: 1 year
This warranty period applies unless otherwise agreed
to in writing.
This warranty excludes: 1) Kilns or furnaces damaged
by overfiring (exceeding the melting temperature of the
material being fired) regardless of cause of overfiring; 2)
Ware, tools, kiln furniture, or anything inside damaged by
overfire; 3) Kilns allowed to exceed the maximum temperature shown on kiln’s nameplate, regardless of cause;
4) Kilns subjected to abuse, neglect, freight damage or
improper storage; 5) Kilns used for either reduction or
salt firing, 6) Kilns damaged by improper electrical installation; 7) Kilns used for purposes other than firing ceramics, glass, heat treating, or the purpose for which it
was intended; 8) Element burnout caused by contact with
foreign materials.
Paragon Industries, L.P., will repair or replace any
parts that become defective under normal and proper use
during the specified period for the kiln purchased, providing the kiln has not been subjected to misuse or the
listed exclusions. Paragon will furnish and install replacement parts at the factory with transportation costs to
and from the factory paid by the owner; or upon receipt of
defective parts at the factory, and after factory examination of the defect, Paragon will furnish replacement parts,
complete with installation instructions, shipped postpaid
to owner. The warranty on the repaired and/or replaced
parts will be limited to the unexpired term of the original
Any claim for adjustment under this warranty must include name and address of dealer from whom kiln was
originally purchased. Repair or replacement of any defective parts shall fulfill all obligations of Paragon. No other
obligations or liabilities are assumed in connection with
Paragon kilns nor does Paragon Industries, L.P. authorize its distributors or dealers to assume any other obligations or liabilities on its behalf.
This agreement is made in the State of Texas and its
validity, construction, and all rights under it will be governed by the laws of the State of Texas. This warranty
gives you specific legal rights, and you may also have other
rights, which vary from state to state.
Free video training! Watch
kiln videos at
Click the “Audio & Videos” link
near the top
of the home page.
2011 South Town East Blvd.
Mesquite,Texas 75149-1122
Toll Free: 800-876-4328
Toll Free Fax: 888-222-6450
Fax: 972-222-0646
[email protected]
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