Paragon Glass Kiln, TNF663 User Manual

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Beadmaking, Glassblowing,
Fusing and Glass Kiln
Manual
Sundance
Glass
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Introduction
Contents
Please read this manual. It will help you gain the maximum enjoyment from your kiln. It will show you how to avoid damag
­ing the kiln and will answer many questions. Your instruction packet also includes a separate digital controller manual. Please save both manuals.
Inspect the kiln. When you receive your kiln, check the carton for damage (crushed, holes, etc.). Check the kiln for both inte
­rior 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.
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 immediately.
Save the shipping carton. 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 repairs.
Needless worries. 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 sur
­face 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 around the door will eventually discolor from heat. This, again, will not affect the kiln’s performance.
Safety 3 Setting Up the Kiln 4
Electrical Installation. . . . . . . . . . . . . . . . . . 4
Where to Locate the Kiln . . . . . . . . . . . . . . 4
Transporting the Kiln . . . . . . . . . . . . . . . . . 4
Basic Operation 5
Accessories . . . . . . . . . . . . . . . . . . . . . . . . 5
Important Guidelines . . . . . . . . . . . . . . . . . 5
Loading the Kiln . . . . . . . . . . . . . . . . . . . . . 7
Venting the Kiln . . . . . . . . . . . . . . . . . . . . . 8
Silver & Gold Clay 8
Drying Time . . . . . . . . . . . . . . . . . . . . . . . . 8
Loading the Kiln . . . . . . . . . . . . . . . . . . . . . 8
Venting the Kiln . . . . . . . . . . . . . . . . . . . . . 9
Rate, Temperature and Hold . . . . . . . . . . . 9
Cooling Time . . . . . . . . . . . . . . . . . . . . . . . 9
Combining Silver Clay
With Other Materials. . . . . . . . . . . . . . . . . . 9
Glass Fusing & Slumping 10
How to Cut Glass . . . . . . . . . . . . . . . . . . . 10
Fusing Compatibility of Glass . . . . . . . . . . 10
The Annealing Range . . . . . . . . . . . . . . . . 10
Cleaning and Gluing the Glass . . . . . . . . . 11
Loading the Kiln . . . . . . . . . . . . . . . . . . . . 11
Firing the Glass . . . . . . . . . . . . . . . . . . . . . 11
Enameling on Metal 12
Preparing the Copper . . . . . . . . . . . . . . . . 12
Decorating the Copper . . . . . . . . . . . . . . . 12
Firing Enamel . . . . . . . . . . . . . . . . . . . . . . 13
Ceramic Overglaze 13
Pyrometric Cones . . . . . . . . . . . . . . . . . . . 13
Loading and Firing Overglaze. . . . . . . . . . 13
Lost Wax Burnout 14
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 14
A Sample Program . . . . . . . . . . . . . . . . . . 14
Burnout Instructions . . . . . . . . . . . . . . . . . 15
Firing Mistakes 15
Silver Clay . . . . . . . . . . . . . . . . . . . . . . . . . 15
Glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Ceramic Overglaze . . . . . . . . . . . . . . . . . . 16
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.
The Electrical data plate. Im portant information about your kiln is recorded on its electrical data plate. Please include this in
­formation when ordering parts or calling your dealer or the factory about your kiln.
©2001, IM-164/1-02
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Kiln Maintenance 17
Trouble-Shooter . . . . . . . . . . . . . . . . . . . . 17
Door Latch Adjustment . . . . . . . . . . . . . . . 17
Ceramic Fiber Repair . . . . . . . . . . . . . . . . 17
Cleaning or Replacing Glass View Port . . 17
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Replacing the Thermocouple . . . . . . . . . . 18
Replacing a Relay or Transformer . . . . . . 18
Replacing the Temperature Controller . . . 19 Replacing the Firing Chamber
(testing the element) . . . . . . . . . . . . . . . . . 19
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Safety
Overfiring
The warranty on your kiln does not cover damage from overfiring, regardlessofthecircumstances.Itisthe 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!
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 make 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 variations.
Important Safety Rules
An electric kiln is extremely safe to operate provided you
follow these basic safety rules:
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Unplug kiln when not in use.
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Do not touch hot sides.
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Keep unsupervised children away.
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Place kiln on a non-combustible surface.
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Do not installcloser than 12” from any wall or combustible surface.
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Fire only in a well ventilated, covered and protected area.
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Keep cordset away from hot sides of kiln.
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DANGEROUS VOLTAGE: Do not touch heating elements with anything.
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Disconnect kiln before servicing.
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Do not leave kiln unattended while firing.
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Wear safety glasses when cutting glass.
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Wearfiringsafety glasses when looking into a hot kiln.
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Keep food away from your work area.
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Never fire tempered glass inside a kiln. It could explode.
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Avoid firing toxic materials inside the kiln, suchas styrofoam (used as a coreforhollow beads).
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Kilnswiththeglassviewport:do notfirethe kilnhotterthan1700°F/926°C.Firinghotter will damage the glass.
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Setting Up the Kiln
Electrical Installation
Youmustplugyourkilnintoacircuitthatnootherappli anceuses whilethekiln isfiring.Turnoffthecircuitbreaker or unscrew the fuse for the circuit that your kiln will be pluggedinto.Checktosee ifotherappliancesshutoff too. If that circuit powers appliances that must re main on while the kiln is firing,plugyour kiln intoa different circuit.
Note: 120 volt kilns: avoidextensioncords 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!
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2 Remove gasoline, paint, and other flammable
materials from the kiln room.
3 Providea minimum of 12 inchesclearancebetween
kiln and the closest wall.
4 Never allow the room temperature of your firing
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roomtoexceed100-110°F.Measurethe tempera tureabout3feet fromthekiln.Ifnecessary,usefans to lower room temperature.
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Voltage fluctuation can vary firing time from as little as halftomore 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
1 Place your kilninawellventilated, covered andpro
tected area such as the garage, basement, utility or hobby room.
Note: Somepeople keeptheir kilnoutsideon acov eredpatio. Thisisokaysolongasthekiln isnotsub jected to excessive humidity. We recommend good ventilation.However,somematerials,suchas silver clay, may not need special ventilation.
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Place the kiln on a fire-proof surface, such as a large ceramic kiln shelf.
5 Keepthekilnawayfromcurtainsorothercombusti-
ble materials.
6 Position kiln on a level, fire-proof surface. We rec-
ommendan18” x 18”pieceofsheet metaloralarge ceramic kiln shelf.
Note: Ifyou are with the kiln at all times during fir ing, you can place it directly onto a workbench or kitchen table. A fire-proof surface is ideal, though, becauseitprovidesa safe placetolayhotshelves re moved from the kiln.
7 Keep unsupervised children away. 8 Keepthepowersupplycordawayfromthekilncase.
There is little danger of serious burn from accidental contact if you exercise the same caution you would use with an electric iron.
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Transporting 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.
Ifyounolongerhavethepackingmaterials,transportthe kilnonits back with the door facing up. Place a thin sheetof foamcushioning betweenthedoor andthefiringchamberto prevent rubbing. Avoid subjecting the kiln to excessive vi bration during travel.
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Basic Operation
Accessories
Ceramic Fiber Shelves
The soft ceramic fi ber shelf, which comes standard with the kiln, cradles gold and silver clay pieces. These shelves are not suitable for firing glass or ce ramics.
Ceramic Fireclay Shelves & Posts
Ceramic fireclay shelves, available from Sundance are hard ce ramic 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 kilnwash are mixtures of finely ground minerals that will not melt and fuse together at high temperatures. They pre vent 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.
Aspowders,glass separatorandkilnwash haveanunlim
ited 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.
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Alumina Hydrate
Delicatesilveror goldclayshapesmay needextrasupport duringfiringtopreventwarping.Placetheseshapesinathin layerofaluminahydrateinsideasmallceramicbisquebowl. Do not breathe alumina hydrate.
Stilts
Stiltsarepoints embedded in a ceramic base. The points separate enameling and glazed ceramics from the shelf.
The wire mesh above is referred to as an enameling rack. An enameling fork lifts therack out of thekiln. A stiltseparates the piece fromthe rack.
Enameling Racks
Enamelingistheartoffiringglassontometal.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.
The heating element under power is dangerous. Do not touch the element with anything! Turn the kiln switch off beforeinsertinganenamelingforkintothefiringchamber.
Fiber Repair Filler
Thisisa permanent,hightemperature refractorycement used to repair holes or cracks in the ceramic fiber firing chamber.
Safety Glasses
Wear clear safety glasses when cutting or chipping glass. Wear firing safety glasses when
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looking into a hot kiln, such as when checking the progress of glass.
Caution: Always wear fir ing glasses when viewing the interior through the optional glass view port.
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Important Guidelines
The Embedded Heating Element
Theheatingelementsofyourkilnareembeddedintothe ceramicfiberfiringchamber.Thefiringchambersurface is hardenedtoadepthof¼”.Thismakesthefibermoredura ble. 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.
Note: Theheatingelementunderpoweris danger ous.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 if 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, ex tending into the firing chamber. The digital controller senses temperature by reading a voltage from the thermo­couple. If this rod is pushed out of the firing chamber, the kilnwillassumethat the firingchamberiscold.This will re­sult in an over-fire. Be sure the rod extends into the firing chamber by ½” - ¾” before firing the kiln.
Vacuum the Kiln
Clean the kiln before firing glass, enameling, or ceramic glaze. (Cleaning is not necessary when firing silver or gold clay).Usea softbrushnozzleon avacuumcleanerto remove dust from inside the kiln.
Removing Hot Ware
To remove hot ware from the kiln, turn off the kiln. Carefully slide an enameling fork un der the shelf. Place the hot shelf on a large ce ramickilnshelfin front of the kiln. Wear thick work gloves.
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Firing Log Book
Record the following information in a firing log book:
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Date
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Firing temperature, speed and hold; or Ramp/Hold pro gram
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Starting time
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Total firing time
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Type of pieces
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Firing results
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Asyou gain experience, you will finda wealth of informa
tion in your firing logs.
Low Temperature Holds
A low temperature hold (i.e. 200° - 300°F) is more diffi
cult to maintain than higher temperature holds (1400° -
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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. Otherwisethetemperaturemayovershoottheholdtemper ature before the element turns off.
Avoid Contaminating the Heating Element
Contact with silica or silica bearing com pounds, such as kiln wash, glass separator, alumina hydrate, glass, enameling powder, and ceramic glaze, will ruin the heating element.
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Neverfireglazed 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.
Caution: Some kilns contain a heating element embeddedinthe bottomofthefiring chamber.Ma­terials such as glass and glaze, if absorbed into the fiber firing chamber, can ruin the element. This type of damage is not covered by warranty. Prevent glass separator, kiln wash, and alumina hydrate from falling from a shelf onto the firing chamber. These materials can destroy the element.
Note: If a contami nantsuchasdripping glassorglaze embeds into the firing cham ber, unplug the kiln. Gently scrape off the contaminant with a knife, being careful not to damage the heatingelement.Vac uum the kiln.
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The Effect of Silver Residue on Glass
Firing silver clay leaves traces of silver in the poresof the firingchamber.Sometimesthere is enough silverresiduein
­the kiln to affect colors of glass. 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 clearglass.Placethe glassonafireclayshelf(notthe soft fiber shelf).
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The Optional Glass View Port
Caution: Wear fir ing safety glasses whenever looking into the optional view port.
Maximum tempera ture for a kiln with view port is 1700°F/926°C. Firinghotterwilldamagetheglass.Seepage17forglassport maintenance instructions.
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Loading the Kiln
Place Ware on a Protective Shelf
Alwaysprotectthefiringchamberby firingyourpieceson a shelf or in a bowl. Do not place the pieces directly on the bottom of the firing chamber.
Types of shelves and containers:
Fiber Shelf
Place the standard fi ber shelf directly onto the kiln bottom. This shelf is used to support silver and gold clay.
Note: Fireonlysilver or gold clay on the fi­ber shelf—never ce­ramics, enameling or glass. Do not coat the fiber shelf with glass separator or kiln wash.
Fireclay Shelf
Ceramic fireclay shelves, available from
Sundance protect the fir ing chamber bottom and provide a smooth surface. Use a ceramic shelf in yourjewelry kilntofirece ramics, glass, and enameling.
Insulating Firebrick Piece
Insulating firebricks are porous, light-weight, and canbe shapedtosup port delicate silver clay designs. Carve the fire brickwithaknifeorhack saw.
Ceramic Bowl
You can purchase an unglazed, small ceramic bisque bowlfroma ceramic supplystore.Thebowl willlastthrough many firings. Use it to hold alumina hydrate. You can also shape hot glass by slumping it into the bowl.
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Note: Ceramic shelves and bowls and insulating firebricks may slow the firing. They absorb more heat than the ceramic fiber shelf. They also cool more slowly than the fiber shelf.
Applying Glass Separator or Kiln Wash
Glass and ceramics are fired on a fireclay kiln shelf and notdirectly onthekilnbottom.Youcanalsoslumpglassover amold, suchasabowl.The kilnshelfandsaggingmold must becoatedwithglassseparatortokeepglass 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.
Whenrecoatingashelf,re move most of the old coating with grit cloth (available from sundance). This is an abra sive-coated mesh that allows residueto pass through. Removing the old coatinggivesyou a smooth surface to start with. Then recoat the shelf using thefollowingdirections. (Both glassseparatorandkilnwash will be referred to as “separator.”)
Caution: Donotapply glass separator or kiln wash totheceramic fiber firingchamberorto the bottom of the shelf! Contact with glass separator or kiln wash can ruin 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 withglass, however, fire the piece on ahard fireclay shelf coated with separator.
1 Mix the separator with water followingthedirections
on the bag. Stir.
2 Useahaik brush or a soft
paint brush to apply the separator to the shelf. (The haik brush is easier to use because it lays down a more even coat ing.) Each time you dip your brush into the sepa rator 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.
3 Drytheshelf beforefiring.Tospeeddrying,placethe
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.
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Separator lasts through several glass firings. Apply new separator when the oldcoat begins to flake.
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4 Afterthe separator has dried and your shelf is cool,
youcansmoothen the separator further by rubbing your hand lightly over the shelf. The smoother the separator,thesmootherthe backsideoftheglass.
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
Ceramic posts support ceramic fireclay shelves inside a kiln.
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Donotuse postsundertheceramic fibersoftshelf.Place the fiber shelf directly onto the bottom of the firing chamber.
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Place three ½” posts under the ceramic hard fireclay shelf. This aids air circulation, preventing heat built-up under the shelf.
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Youcan firetwoormoreceramicfireclayshelvesinaPar agon 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 de pends on the size of the kiln. When you load multiple shelves,fireataslowerrate.Thisaidsheatdistribution.
Silver & Gold Clay
Withsilverclay, it ispossibletoshape intricate,free-form silver jewelry in minutes—even as a beginner. (The clay is alsoavailablein gold;forsimplicitywe willrefertoboth met als 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 withsimpletoolssuchas a tooth pick, small knife, and razor blade. Its surface is pliable and accepts impressions from objectssuchasleaves,coins,andcoarsefabrics.Afterthesil ver clay is formed, it is fired in a kiln. The recommended temperature and hold time is included with the silver clay.
Formingandfiringsilverclayissimple.Thereisnothing mysterious about making silver clay jewelry. The silver clay is made of micron-size silver (or gold) particles held in an
­organic binder. During firing, the binder burns away. The
silver particles then fuse together forming real silver. Since thebinder disappears,thereisacertainamountofshrinkage
­duringfiring. Shrinkage varies depending onthe type of sil
ver clay you use.
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Venting the Kiln
Some types of ware, such as glass and ceramics, contain impurities that burn off during firing. These impurities mustbe releasedfromthekiln.Otherwise theycanaffectthe quality of the ware.
Silver and gold clay need no venting unless you are firing themwith amaterialthatburnsout forahollowshape,or you are combining them with another material such as glass.
Ifthekiln hasavent hole,openthevent. Ifitdoes nothave a vent hole, open the door about ½”. Venting will be ex plained in greater detail in sections on glass and ceramics.
Drying Time
Small, thin silver clay pieces can be placed into the kiln whilestill moist, and fired. Thicker pieces need time to dry. Otherwise they may warp during firing.
Tobeon thesafeside,givethe silverclayplentyof time to dry. As you gain experience, you will know just how much drying time each type of piece needs. You can speed drying with a hair dryer.
Loading the Kiln
Silverclaypiecesthathaveaflatsidecanbeplaced inside the kiln directly onto a shelf. Use the soft ceramicfiber type shelf. It cushions the clay silver.
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Silverclaypiecescanbeclose together,butthey mustnot touch.
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The soft ceramic fiber shelf can be placed directly onto thefiringchamberbottom. It is not necessary to support the fiber shelf with posts, since the heat transfers easily through the fiber shelf.
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Donotcoatthe ceramic fiber shelf with kiln washorglassseparator.
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You can also place the silver clay on a piece of ceramic fiber batting.
Alumina Hydrate
Rounded, hollow, or other delicate shapes may needsupport to prevent collapsing. You can lay these pieces onto a mound of alumina hydrate.
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If the piece needs only shallow support of ¼” depth or less, pour the alumina hydrate onto a ceramic fireclay shelf. Support the fireclay shelf on three ½” posts to aid heat flow under the shelf.
If the silver clay shape needs deeper support, pour the alumina hydrate into an unglazed ceramic bisque bowl. These are available at ceramic supply stores.
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Place the ceramic bowl directly onto the kiln bottom.
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NEVERusea glazed bowl to hold the alumina hydrate. If the glaze runs, it can embed into the firing chamber.
Caution: Avoid breathing alumina hydrate dust. Caution: Alumina hydrate can destroy the heating
elementoncontact.Ifitspillsontothefiringcham ber, remove with a vacuum cleaner.
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combination, eliminating the need to visually check the glass.
Venting the Kiln
Silver clay by itself needs no venting. Load the kiln, close thedoor,andleaveitclosed untiltheclay silverisready tore move.
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.
Paper maché and paper clay are good core materials. Do not use wax or styrofoam as a core. They emit harmful fumes.
Rate, Temperature, Hold
Each brand of silver clay fires to a specific temperature andholdtime.Thisinformationisavailablefromyoursilver clay supplier.
Note: Hold time is the length of time that the rec ommended temperature is maintained in the kiln. Do not fire longer than the recommended hold, or the silver will begin to overfire.
Besides selecting a temperature and hold time on your kiln’s digital controller, you will also need a firing rate. (See the separate digital controller instruction booklet.) Select a Full Power rate if you are firing silver clay alone. If you fire glassorceramics withthesilverclay, selectaratebest suited for the glass or ceramics.
Note: Do not place silver clay into a kiln that is al readyhotunlesstheclayiscompletely dry. The kiln should be no hotter than 500°F/260°C when insert ing the silver clay.
After the kiln begins firing, leave the door closed. Do not open the door until it is time to remove the clay. Visual in spection of the clay is unnecessary.
If you are firing glass with the silver clay, on the other hand,youmayneedto check the fusing progress oftheglass by opening the door ½” and looking inside. Look for just a second or two. As you gain experience, you will be able to programthecorrect temperature forthesilverclay andglass
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Cooling Time
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Aftertheclaysilver has fired to completion,youcancrack the door an inch to speed cooling. If you are firing stones, glass,orothermaterialswiththesilverclay,itissafertoallow the kiln to cool slowly with door closed. Remove the piece when the kiln reaches room temperature.
Silver clay pieces that contain no other materials can be removed from the kiln at 1100°F/593°C. You can remove them with tongs and drop them into water.
Caution: Turn the kiln off before inserting tongs into the firing chamber. Wear protective gloves.
Combining Silver Clay With Other Materials
Thereare two ways to fire silver claywith other materials such as glass:
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Fire the silver clay first by itself. After you have cleaned andpolished the silver clay, fire it a secondtimewith the other material.
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Fire the silver clay and other materials, such as a stone, together in a single firing.
Enamelingpowderiseasiertofirewiththe silver clay in a secondfiring.See page12.Glassis oftenfiredwiththesilver clay in a single firing. Many types of glass will melt to the point of overfire at silver clay temperatures. So before combiningglassandsilverclay in a single firing, test a small sample of the glass. 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 piece.) Place theglasspiecesonaceramicfireclayshelf. Youmustcoatthe shelfwith glassseparator,orotherwisetheglasssamplewith
­embed into the shelf.
If the glass sample survives the firing, you can fire that typeofglasswithsilverclayin 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.
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Glass Fusing &
2 Hold the straight edge firmly and score the glass
withtheglass cutter.Pressjusthard enoughsothat the scoring noise sounds steady and unbroken.
Slumping
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 ex plode if heated inside a kiln.
Basic Glass Tools
Reservoir Glass Cutter uses a reservoir of oil to lu
bricate the cutter wheel.
Running Pliers are for cutting large pieces of glass.
Breaking Pliers are for cutting small strips.
Grozing Pliers shape the glass by chipping away the
edges.They areoftenusedwhenthescoreline doesn’tbreak 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.
1 Lay the glass on a clean surface. Mark off the cut
withagreasepencilor felt-tip pen. A smallmarkon each end of the glass will do. Lay a wooden straight edgeoverthe glassandlineit upwiththemarks you just made.
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3 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 con
tracts.Therateatwhich glasschangessize iscalledthecoef
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ficient of thermal expansion. If you fuse two glass pieces to gether and one changes size faster or slower than the other, the fused piece may crack—even several months after fus ing.
Whendifferentglasses have a close enough coefficient of expansiontofusesuccessfully,they’recalled fusing compati ble. Buy glass labeled fusing compatible. Or fuse glass that has been cut from the same sheet, which guarantees com patibility.
Fusing Compatibility Test
1 Totestglassforcompatibility,fusesmall½”square
samplepiecesof differentglassesontoa largerbase piece of clear transparent. It should extend beyond thesmall samplepiecesbyhalfaninchon eachside. One of the sample pieces should be cut from the base piece.
2 Heat the glass to a temperature that completely
rounds the edges of the small sample pieces.
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3 After the glass cools, place a polarizing filter under
the glass and another filter over the glass. Look at theglasswith lightshiningthroughit (hold itovera lamp).Turn one of the filters until the filters areat their darkest.
Results of the Test
Ifyou see a halo around the edges ofthe small glass sam ples,thisusuallymeanstheglassisnot compatible.Ifyousee 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 thetestagain,thistimecoolingmoreslowlythroughthean nealing range.
The Annealing Range
Each type of glass has a temperature range that it must passthroughslowlywhenitcools.Thisiscalledtheanneal ing range. This slow cooling gives hot glass time to release thestressofcooling.Ifyoucooltheglass toofastthrough 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
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on the side of caution if you aren’t sure how long to anneal. Smallprojectssuchasearringsrarelyneedannealingtimeas they cool.
Cleaning and Gluing the Glass
Grease, dirt, and fingerprints etch per manently into the glass during firing. Clean the glass with glasscleaner(thetype without silicones), rubbing alcohol, or even plain water just before assembling the pieces on the kiln shelf.
Use white glue, such as Elmer’s diluted1:1with water, to hold the glass pieces together after you place them on the kiln shelf. Use the gluesparingly.Glueis especially important whenfusing wire into the glass. The glue prevents the glass or wire from moving out of place before they fuse. The glue disappears during firing.
Avoid using glue on the coated side of dichroic glass. If youlaydichroicglasscarefully onto the piece, glueisunnec­essary,soavoiditaltogether if you do notknowwhichsideof the dichroic is coated.
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Loading the Kiln
Air should circulate between the shelf and the bottom of the kiln, so place three or four 1/2” posts in the kiln. Lay the shelf over the posts.
Firing the Glass
1 Vent kiln by openingthedoor½”and leaving thevent
hole (if your kiln has one) open. Venting allows the gasesreleasedto escape. Whenthekilnreaches500 ­800° F / 260 - 426°C, close the door.
2 The first time you fire a particular brand or type of
glass, program the controller for a higher tempera
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Looking at the glass during firing. Open the door about ½”. Always wear firing safety glasses when looking at the hot glass.
ture 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 glass fuses the way you want. Make a note of the shut-off tempera ture. For future firings, program the kiln for that temperature and rate.
Note: With everyfiring,besureyou arenearthekiln before the expected shut-off time.
3 After you shut the kiln off, vent the kiln for five min-
utes by opening the door 1”. Then close the door.
Note: Someglass artists flash cool the glass after it fuses. They vent the kiln until the temperature drops to 1000° F. Then they close the door again. This speeds up cooling.
4 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 seg ment for cooling. See the kiln’s digital controller manual.
Note: For safest cooling, leave the ware inside the kilnuntilthe 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 com pletely, remove the shelf also. Leave the pieces on the shelf untilthey reachroom temperature. The heat in the shelf will help prevent them from cooling too quickly.
Caution: Beforeremoving a shelf,turnoffpowerto the kiln.
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Enameling 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 readytouse. Noenamelwashingisrequiredforthese enam els.
Startwithoneof themanypre-shapedcopperformsavail able, or shape and trim the copper to your own design.
1 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 hasvaporized.Do not fire the copper any longer than this point. Otherwise excess fire scale will form, making the next cleaning step difficult.
2 After the copper cools, brush any loose scale from
the copper. Use a brush or paper towel, being sure thatyoudonotput anygreaseor oilontothe copper,
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.
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Counter or backing enamel, a mixture that gives a mot tled effect, can be used for counter enameling. Or you can useregularenamel.Counter enamelisappliedbythe 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. Youcanpurchaseamaskingpreparationfromyoursupplier tohelp prevent fire scale. You must place thepiece on a stilt whenfiringtheother(front)sideofthepiece.Thestiltpre­vents the back of the counter enameled piece from sticking to the enameling rack.
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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 re quired. Additional copper cleaning products are availableintheThompsonEnamel Catalog,includ ing Sparex No. 2.
Itisbesttocleanthe copper just before you decorate it.If youwaittoo longtodecorateafter cleaning,thecoppercould get dirty again.
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Applying Enamels
Apply enamel over a clean sheet of paper so you can pour theexcessbackintothebottle forreuse.Transparentenam els should be applied in several thin coats. Transparent enamels can be mixed with fairly good results. If opaque enamelsaremixed,however, agrainyeffectresults.The two basic methods of applying enamels are sifting and spatula.
Sifting Enamel
SprayorbrushThompsonholdingagentontothecopper. Thensifta1/32”layerof enamel onto the copper. Usea#60 meshsifter.Ifthecoatis too thin, you can easily addanother 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 manydifferentcolors.UsingadilutedsolutionofThompson 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
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agenttokeepthegrainsof enamelinplace. Allowtheenamel to dry completely before firing.
Ceramic Overglaze
Firing Enamel
1 Heat the kiln to 1450°F/787°C for most enameling.
Use a Single Segment. (Please see your digital con troller instruction manual.)
Rate Temp.
Segment °F/°C °F/°C Hold
1 1799/999 1450/787 01.00
Note: Hold time should be the length of time you will be inserting enameling into the kiln. In the above example, hold time is for a one hour.
2 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 shouldbefiredwitha stiltevenif thepiecehas aplain bottom.Use anenamelingforkor,iftherackis small, a 6” putty knife, to place the rack into the kiln on top of ½” ceramic posts.
Note: Firing the piece at enameling temperature shouldtakeabout threeminutesandrequires undi­vided attention!
3 Look at your pieceevery15secondsbycrackingopen
thedoor.Removethe rack whenthecopperpieceap pears a rosy red and the enamel is smooth. Place the rackonasteelpadorlargeceramickilnshelfandletit cool completely.
4 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.
Pyrometric Cones
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Pyrometric cones are small pyramids of clay and mineral oxide that soften and bend whenexposedtoheat.They indicatewhenceramic ware has fired to maturity.
Pyrometric cones come in 1 1/8" and 2 ½" lengths. Use the 2½” cones. Cones mounted on the kiln shelf mustbeslanted8° fromver tical.Theywillnotbendac curately if they are slanted to the wrong angle. Self-supporting large coneshave thecorrectslant built into the base. Stan dard cones must be mounted in a clay or wire plaque.
The chart on page 14 shows the temperatures of pyrometriccones.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 temperature shown in the 108°F column of the Tem perature Equivalents chart for the cone number you are firing.
Before deciding on the firingspeedofimportantpieces,testfiresampleclaypieces.
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.
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A self-supporting cone fired to matu rity. Do not be concerned if the tip is slightly higher or lower than shown.
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A “puddled” over-fired cone.
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Under-fired cone.
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Loading and Firing
Overglaze
Overglaze is decoration applied over fired glaze or pol ished porcelain bisque. Overglazes include china paints, gold, and luster, which fire from cone 022 to 014.
Load overglazed ware the same way you would load ce ramic glaze. Use stilts and make sure ware is not touching other ware. Ware must be completely dry before firing.
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China paints will crack or peel if ap plied heavily. Apply several light coats in stead, firing between each,untilyougetthe shade you want. Not all china paint colors reach maximum colorsaturation atthe same temperature even when fired on thesameware.Soyou mustknowwhichcol ors you should fire first at higher tem peratures 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 beenfired.Reds and yellowsshouldnotbe fired sidebyside. Colorsalsomatureatalower temperatureonceramic pieces thanonporcelainorhardchina.Checktheoverglazemanu facturer’s literature for information on which cone to use with each color and type of ware.
Vent the door during the first hour of firing. If your kiln has a vent hole, leave it open during the entire firing. Allow kiln to cool to room temperature before opening the door.
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Open the door ½” to vent the kiln if your kiln
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does not have vent holes.
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Temperature Equivalents For Orton
Self-Supporting Pyrometric Cones
Cone
Cone Self-Supporting Cones Pre-Fire
Number Color
Heated at: 27° F 108° F 270° F
Per Hour* Per Hour* Per Hour*
022 1087 1094 Green 021 1112 1143 Fuschia 020 1159 1180 Orange 019 1213 1252 1283 Yellow 018 1267 1319 1353 White 017 1301 1360 1405 Pink 016 1368 1422 1465 Light Blue 015 1382 1456 1504 Violet 014 1395 1485 1540 Gray 013 1485 1539 1582 Green 012 1549 1582 1620 Fuschia
*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 or4-½”posts inside the kiln. This prevents the element from possibly shorting out against the tray.
Note: Theseinstructionsapply toinjectionwaxthat melts at 200°F, not pattern waxes and plastics that meltathighertemperatures.Ifsmokeappearsdur ing wax elimination, turn off the kiln. Smoking wax means the kiln fired hotter than 300°/148°C.
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Overview
Lostwaxcastingistheprocessofcarvingashapeinwax, andthencasting that shape in metal. After the wax has been carved,amold is madeofthewax shape. Themoldisa nega­tiveimageofthewax.Thewaxislatermeltedoutofthemold through hollow channels called sprues.
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:
1 Melt the wax from the mold. 2 Remove wax from the kiln before raising the tem-
perature higher than 300°F/148°C.
3 Harden the mold at high temperature. 4 Maintain the mold at the casting temperature rec
ommendedforthetypeofmetalthatwillbepoured into the mold.
Caution: Prevent wax or carbon from contacting the kiln’s walls and elements. Carbon build-up in sideakilnruins the interior.Carbonconductselec tricityand causeselementstoshortcircuit. Damage to elements from contact with foreign materials is not covered by warranty.
A Sample Program
See your digital controller instruction manual to enter this program:
Rate Temp.
Segment °F/°C °F/°C Hold
1 500/277 300/148 01.00
2 500/277 1350/732 01.00
3 450/250 800/426 02.00
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Segment 1 heats the wax to 300°F/148°C and holds it for
one hour, allowing it to drip from the mold.
Segment 2 hardens the mold.
Segment 3 lowers temperature to 800°F/426°C, the typi calcastingtemperatureforsilver.(Most types of gold cast at 900°F/482°C.)
Note: Casting temperature depends on the size of themold.Thetemperaturesaboveareonlyaguide. See your jewelry supply dealer for temperature recommendations.
Burnout Instructions
1 Place a metal tray inside the kiln on three ½” posts.
Place the mold on a wire mesh screen on top of the tray.Themold’ssprueholeshouldbedown.Thetray willcatchmeltingwaxasitdripsfromthespruehole.
2 Keep the kiln’s vent hole(s), if 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 one hour.
Note: Do NOT heat the wax above 300°F/148°C. Hold at 300°F/148°C for at least one 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 expensive damage.
3 Afteronehourat300°F/148°C,openthe kiln.Remove
themoldandwaxtray.Pourthewaxfromthetray and leavethetrayoutofthe kilnuntilyour nextwaxelimi­nation. (Do not leave the tray in the kiln!)
4 Heat the mold to the temperature recommended by
yourjewelers’supplyhousewhereyoupurchasedthe moldmaterial.Thisisusuallyaround1350°F/732°C.
5 Lower the temperature tothecastingtemperatureof
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
Ifyoufollow theabovedirections,yourkiln shouldbesafe from wax damage. In some cases, a small amount of carbon mayformonthewallsoveraperiodoftime.Thisisduetothe burningof waxresiduethatwasleft inthemold.Forthis rea son we recommend that you periodically fire the kiln to 1500°F/815°C as follows:
1 Open the vent cover(s) or leave the door ajar ½”. 2 Fire the kiln empty to 1500°F/815°C at a rate of
300°F/166°C with a one hour hold (01.00).
Firing Mistakes
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Silver Clay
Cracks
Cracks that appear in fired silver clay may be due to too much water in the silver clay before it was fired. Another cause is careless handling of a dried, unfired piece. To re pair, fill the crack with silver clay and fire again.
Brittle
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.
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 page17,bottom left column).Replacethethermocouple if it is old.
Glass
Glass Cracking
Probable Causes:
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Heating the Kiln Too Fast
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Cooling the Kiln Too Fast
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Fusing Incompatible Glass
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Not Enough Glass Separator on Shelf
Mostproblemsin fusing arecausedbyrushing the firing. Theglass must change temperature slowly during the criti cal temperature range of 100° - 500° F / 37° - 260°C. This critical range applies to both heating and cooling.
The second critical temperature range is annealing, whichis thecoolingrangeof950°-700°F/510°-371°Caver age. Cool the glass slowly during this range so the stress in the glass will have time to dissipate.
If you become im patient after the glass has fused and you crack open the door of the kiln for a few sec onds to peek inside,
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you may hear a “ping,” which is the sound of glass cracking. Avoid the temptation to open thedoor.Waituntilthe kilnhascooled toroom temperature. Some artists schedule their fusingsothatitiscom pletedbefore theygoto bed. That way they will
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Flaking glass separator can cause the
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glass to crack. This is because the glass sticks to the shelf.
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beasleep while the glass cools andthey won’t be tempted to open the door.
After each firing, examine the shelf. Recoat if the kiln washischipped.Whenglassstickstoabaresectionofshelf, the glass cracks.
Glass Bubbles
Probable Causes:
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Heating the Kiln Too Fast
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Air Trapped Between Layers of Glass
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Grease or Dirt Between Layers of Glass
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Uneven Glass Volume
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Moisture or trapped Air Between the Glass and Shelf
Makesuretheshelfiscompletelydrybeforefiring.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 tempera ture of the glass.
Glass Devitrification (Frosty Surface)
Probable Causes:
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Impurities in Glass
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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, some artists vent the door of the kiln slightly afterfusingiscompleted.Theyclosethedoorwhentheglass reaches 1000°F/537°C.
Glass Separator Sticks To Glass
Probable Causes:
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Firing Too Hot
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Overglaze On the Back of the Piece
Instead of firing to a full fuse temperature, try firing 50°F/28°Ccoolerand holding atthattemperatureforseveral minutes.
Ceramic Overglaze
Breaking in Overglaze Firing
Canbecaused bypoorlyfired bisque.Aslowbisque fireis 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
Usuallydueto athinapplicationof goldortoo muchthin ner.Ifgoldis applied accidentally to anareaitwillshowpur ple after being fired unless cleaned with a good gold re mover.
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
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Can be caused by the paint being applied 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 withachinapaintbackground,apply andfirethe decalsfirst, thenchina paintandfireagain.Checktherecommendations ofdecal supplier.Ifdecalwasunderfired,refiretoproperfir­ingcone.Ifdecalwasoverfired,the design may be repainted in china paints and refired.
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 placedinthekilnorfrom having been fired at the sametime as other overglazes.
Note: Apply lusters only on a dry day.
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Powdering of Luster Colors
This can be caused by too heavy an application.
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Kiln Maintenance
Trouble-Shooter
Kiln Does Not Turn On, Display is Blank
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Make sure the circuit breaker is in the “on” po sition.
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Ifthecircuitbreakerison, check the kiln’s fuse. Re move by pressing on the fuse holder and turning counter-clockwise half a turn. Check the fuse by placing the probes of an ohmmeter on the ends of the fuse. If the ohmeter reads less than one ohm (digital meter) or reads 0 ohms (analog meter), the fuse is bad. Replacement fuse:
AGC ½ A 250V AC
Note: If you do not have an ohmmeter, visually in­spect the fuse. You will see a thin strand of unbro­ken wire in a good fuse. The wire usually appears broken in a burned fuse.
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Kiln Repairs
Door Latch Adjustment
Adjustthetwoscrews on the door latch to change the spring ten sion.
Note: Do not loosen the screws too far, or they could fall out.
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.
1 Unplug the kiln. 2 Cutorscrape the ceramic
fiber to remove the con taminant.Removeaslittle fiberaspossible. If aheat­ing element is located where you are scraping, avoid touching the ele­ment.
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Circuit Breaker Trips
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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.
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If the circuit breaker trips im mediately after the kiln is turned on, the kiln may have a short circuit. Un plug the kiln. Re move the bottom cover and look for a loosewiretouching the case.
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Temperature is Inaccurate
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Make sure the ther mocouple is pushed ½”- ¾” intothefiring chamber.
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Ifthe thermocouple is pushed into the firing chamber, and the temperature is inac curate, replace the thermocouple.
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Thermocouple
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Cleaning or Replacing the Glass Viewing Port
Never fire a kiln equipped with the glass view port hotter than 1700°F/926°C. Firing hotter will damage the glass.
To remove the window:
1 Remove the four
screws holding the glass cover.
2 Remove the glass.
Clean with glass cleaner. To remove scratches, take the glassto an eye glass polisher.
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Replacing the Thermocouple
1 Unplug the kiln. 2 Remove the four screws holding the controller to
the front of the kiln. Carefully remove the control ler.
5 The thermocouple is located in the back of the fir
­ingchamber,held inplacebya metalband.Remove the thermocouple from the kiln.
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6 Bend the new thermocouple between porcelain in
sulators. The thermocouple end should be two in
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­sulators long after bending.
3 Removethe two thermocouple wires from the back
ofthe controller.Theyareheldinplacebybutton or lever type connectors. To remove the wires, lift the levers (or press down on the connector buttons) and pull the wires out.
7 Push the newther
­mocouple into the hole in the firing chamber. The twisted end must extendintothefir
­ingchamberby ½”
- ¾”. Make sure the band holds the thermocouple. Otherwise, the thermocouple can be pushed out, re
The band must secure the thermocou ple. Otherwise the kiln could overfire.
­sulting in an overfire.
8 Thread the thermocouple wires down to the con
troller opening at the front of the kiln. Keep the thermocouple wires away from electrical compo­nents and other wires.
9 Strip½” of insulation from theendsofthethermo-
couple wires.
10 Attach the wires to the back of the controller. One
wire is yellow, the other red. Make sure the wires connect to the correct terminals, which are color coded.
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4 Remove the back cover of the kiln.
Removing the thermocouple.
11 Install the controller and back cover of the kiln.
Replacing a Relay or Transformer
1 Unplug the kiln. 2 Place the kiln on its back. 3 Removethescrewsholdingthesheet metal bottom
tothekiln. Tiltthebottomforward togainaccessto the transformer and relay.
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Replacing the Temperature Controller
1 Unplug kiln. 2 Remove the 4 corner screws holding the control
ler faceplateto the switchbox.Carefullylift outface plate.
3 Disconnect the wires
from the back of the board. You will find twoplugsandtwosin
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gle wires.
4 Connect the wires to
the new board. Rein­stall faceplate.
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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.
4 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.
5 Replace push-on
connectors and wires damaged by heat from a burned terminal. If wire connectorsdo not fit snugly on terminals, gently squeeze the end of the terminal with pliers.
6 Asyou 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 wires.
7 Install the screws holding the bottom to the kiln.
Replacing the Firing Chamber
When the element burns out, the ceramic fiber firing
chamber must be replaced.
To test for a burned out element, you will need an ohm-
meter:
1 Unplug the kiln. 2 Remove the back of the kiln (page 18, left column). 3 Place ohmmeter leads against the element connec
tors. A no-needle-movement reading on an analog meter, or OPEN on a digital meter, indicates a burned out element.
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Replacing the firing chamber is a factory repair.
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