im104 paragon ceramic kiln inst

7/31/2019 IM104 Paragon Ceramic Kiln Inst

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You are about to enter themagical world of custom-fired

ceramics. To safely find yourway around and to master yourkiln, read this manual. Save forfuture reference.


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2 Monitor the kiln during operation!

INTRODUCTIONThank you for purchasing a Paragon kiln. We are confident that the kiln will give you many years of relaxation andcreativeenjoyment. Beforeusingyourkiln, readthe manuals thatcamewithit. Theywillsaveyou manyhoursas youlearn about your kiln. The more you know about your kiln, the more you will enjoy it and the longer it will last.

This manual does not cover the digital controller or the Kiln Sitter and switches. They are

covered in a separate manual included in your instruction packet.

In the instruction packet for your kiln, you should find a copy of Safe Installation of the Electric Kiln, FirebrickMaintenance, and a manual that covers your kilns control system. Please contact the factory if you do not havecopies. You can also find them at www.paragonweb.com. Select Support and then Instruction Manuals fromthe drop menu. The manuals are listed alphabetically.

At www.paragonweb.com select Products, then Books & DVDs from the drop menu. The books we recom-mend will enhance your kiln experience. You can also email or phone us with questions. We are glad to help.

At www.paragonweb.comyou will find online videos for many of theproceduresshown in this manual. As youreadeach section, you can go online to watch an actual demonstration on your computer.

Even though your Paragon kiln may be designed to shut off automatically, check the kilnbefore the expected shut-off time. The warranty on your kiln does not cover damage fromoverfiring, regardless of thecircumstances. It is the operators responsibility to make sure thekiln turns off when the firing is completed. Never leave your kiln unattended near the end ofthe firing.

Check your new kiln frequently during the first few firings and note the color changeinside the kiln. After awhile you can learn to estimate, with considerable accuracy, whenthe kiln is about to shut off just by observing the color.

We are accustomed to using products that stay new looking for yearscars, furniture,cameras.Butkilnsaredifferent. Thehigh temperaturesthey reachgenerate tremendousstresses. Since the insulating firebricks expand and contract with each firing, hairlinecracks will appear in the bricks while the kiln is coldeven in a new kiln. Do not be con-

cerned with these. They are normal. The cracks close tightly when the heated bricksexpand. The cracks functionasexpansion jointsandwillnot affect the firing. Thoughtheinsulating firebrick is fragile enough to carve with a fingernail, it is a miracle of physicsand when properly maintained can survive for many years.

Donotbeconcernedwiththelightthatappearsaroundtheedgeofthelidordoor.Aslongasthelid/doorisclosedallthe way, there is little heat loss. Discolored paint is also inevitable and doesnt affect firing results.

Do not be concerned with the clicking sound that the kiln makes during operation. Digital kilns contain relays,whichsendpowertotheelements.Therelaysclickastheycycleonandofftomaintainthecorrect temperature.Andthe infinite switches of manual kilns make a clicking noise too. You will also hear theelementshum.Thisisonlythe soundof element coils vibratingintheir brickgrooves.Once you becomefamiliar with these sounds, you may find them a reassuring indica-

tion that the kiln is firing normally.

If you call usabout yourkiln, please havethe model number, partnumber (P/N),andvoltage from the kilns electrical data plate handy. (The plate is on the side of theswitch box.) Write that information here for quick reference:

P/N____________________ SN______________ Model______________ Volts____________

Thank you again forpurchasing a Paragon kiln. We wish you many years of relaxation and creative enjoyment withyour new purchase! You will find that owning a kiln will give you the freedom to experiment with new ideas and tofire any time you want. Owning a kiln will take your ceramic skills to a new and exciting level.

2008, by Paragon Industries, L.P. IM-104/11-08

Please do not be concernedwith theline of light that appearsaround the lid. It is normal.


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Fire only in a well ventilated area! 3

CONTENTSIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . 2

Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Important Safety Rules . . . . . . . . . . . . . . . . 4

Setting Up. . . . . . . . . . . . . . . . . . . . . . . . . . . 6Setting Up The Stand . . . . . . . . . . . . . . . . . . . . . 6

Attach the Lock-In Lid Support. . . . . . . . . . . . . . 6

Where to Locate Your Kiln . . . . . . . . . . . . . . . . . 6

Seating the Elements . . . . . . . . . . . . . . . . . . . . . 7

Cleaning the Kiln. . . . . . . . . . . . . . . . . . . . . . . . . 8

The Electric Circuit . . . . . . . . . . . . . . . . . . . 8

Electrical Shutoff. . . . . . . . . . . . . . . . . . . . . . . . . 8

Circuit Breaker Panel . . . . . . . . . . . . . . . . . . . . . 8

Circuit Wire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Voltage Affects Firing Time. . . . . . . . . . . . . . . . . 9

Check the Electrical Installation . . . . . . . . . . . . . 9Preparing The Kiln. . . . . . . . . . . . . . . . . . . . 9

Kiln Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Monthly Kiln Maintenance . . . . . . . . . . . . . . . . 10

Pyrometric Cones . . . . . . . . . . . . . . . . . . . 11

Cone Numbers . . . . . . . . . . . . . . . . . . . . . . . . . 11

Heat Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Using Cones . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Pyrometric Cone Charts . . . . . . . . . . . . . . . 12, 13

How to Position Cones on the Shelf . . . . . . . . 14

Using Cones in Digital Kilns . . . . . . . . . . . . . . . 15

The Bending of the Cone . . . . . . . . . . . . . . . . . 15

Firing Accessories. . . . . . . . . . . . . . . . . . . 16

Preparing To Fire The Kiln . . . . . . . . . . . . 17

Vacuuming the Kiln. . . . . . . . . . . . . . . . . . . . . . 17

Drying Greenware. . . . . . . . . . . . . . . . . . . . . . . 18

Shelf Preparation . . . . . . . . . . . . . . . . . . . . . . . 19

Loading The Kiln . . . . . . . . . . . . . . . . . . . . 21

How to Store Kiln Furniture . . . . . . . . . . . . . . . 21

Guidelines for Loading the Kiln . . . . . . . . . . . . 21

Distances Inside the Kiln . . . . . . . . . . . . . . . . . 22

Glazed Ware . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Heat Distribution Inside the Kiln . . . . . . . . . . . . 23

How to Position Posts. . . . . . . . . . . . . . . . . . . . 24

Bead Rods . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Firing Large Ware Across Half Shelves . . . . . . 24

Tile Holders. . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Firing The Kiln . . . . . . . . . . . . . . . . . . . . . . 25

The Stages of Firing . . . . . . . . . . . . . . . . . . . . . 25

When to Speed Up the Firing . . . . . . . . . . . . . . 25

Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27The Basics of Firing . . . . . . . . . . . . . . . . . . . . . 28

The First Firing in Your New Kiln . . . . . . . . . . . 29

Loading and Firing Low-Fire Greenware . . . . . 30

Loading and Firing Low-Fire Glaze . . . . . . . . . 30

Loading and Firing Overglaze . . . . . . . . . . . . . 31

Loading and Firing Ceramic and Glass Decals 32

Loading and Firing Porcelain Greenware . . . . 32

Loading and Firing Porcelain Glaze . . . . . . . . . 33

Loading and Firing StonewareGreenware or Glaze . . . . . . . . . . . . . . . . . . . . . 33

Imperfections. . . . . . . . . . . . . . . . . . . . . . . 34

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Bisque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Glaze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Underglaze . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Overglaze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Porcelain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Kiln Maintenance . . . . . . . . . . . . . . . . . . . . 36

Note:Wheneveryouturn off thecircuitbreakerto your kiln, tape the breaker box door shutand leave a note saying, WORKING ONKILN. BREAKER OFF.

How to Open the Switch Box . . . . . . . . . . . . . . 36

Preventive MaintenanceInside the Switch Box . . . . . . . . . . . . . . . . . . . . 37

Element Maintenance . . . . . . . . . . . . . . . . . . . . 37

Firebrick Maintenance . . . . . . . . . . . . . . . . . . . 43

Tightening the Lid Band . . . . . . . . . . . . . . . . . . 45

Adding a Steel Base Plate . . . . . . . . . . . . . . . . 45

Replacing the Steel Base Plate andTurning Over the Bottom . . . . . . . . . . . . . . . . . 45

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Index . . . . . . . . . . . . . . . . . . . . . . Back Cover

Pottery, as you know, is frustrating. But wecould notfully enjoysuccess ifwedid not experi-ence failure. The whole experience is pro-found.

Steve Burtt


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SAFETYIMPORTANT

Read each page of this manual in detailbefore you install or operate your kiln.

Warranty does not cover damagecaused by failure to follow instructions.

Note: Experienced kiln operators keep a smalltimer withthemasa reminder thatthe kiln is fir-ing. You could set thealarm on a digital wrist-

watch for the estimatedfiring time less 20 min-utes. When the alarmsounds, go to the firingroom to check the kiln.Donotleavethekilnun-attended, especiallynear the estimated

shutoff time.

FOOD-SAFE GLAZES

Some glazes may not be designed forsurfaces that will be in contact with foodor drink. When you make food or drinkcontainers, select a glaze that has beenformulated, tested, and labeled asapproved for surfaces that will be incontact with food or drink. Follow theglaze manufacturer's instructionsexactly, without any variations. Havecustomglazestestedfor foodsafety byalab such as Alfred Analytical Laboratory.

You can learn more about glaze safety inMastering Cone 6 Glazes, by JohnHesselberth and Ron Roy.

Insurance CompaniesIf your insurance company ever inspects your kiln

room, tell the inspector that you follow the safety and in-stallationguidelines shown next. Whatinsurance compa-nies want to see:s Fire extinguishers and smoke detectors.

s Anelectrical shut-off nearthekiln(notneeded for120volt models).

s You have removed combustibles from the kiln room.

s A licensed electrician installed the circuit.

Important Safety RulesFollowing these safety pointers will add little extra

time toyourdailyroutine.Thereis little dangerofseriousburn from accidental contact if you exercise the samecaution you would use with an electric iron.q Place the kiln on the stand recommended by Para-

gon.Whena kiln issafety tested, the lab fires the kiln

on the stand designed for it. Cinder blocks or brickscan inhibit the flow of air under the kiln. They canalso change the kilns heating characteristics.

q Place the kiln on a non-combustible surface.

q Do not install closer than 12" from any wall or com-bustible surface.

q Fireonly in a well ventilated, covered, and protectedarea.

q Do not open the lid until kiln has cooled to roomtemperature and all switches are off.

q Dangerous voltage: do not touch the heating ele-ments with anything.

q Disconnect kiln before servicing.

q Do not leave kiln unattended while firing. Do notleave a kilnturned on atyourstudio while you are at homesleeping.

q Wear firing safety glasseswhen looking into a hot kiln.

q Unplug the kiln, or turn offtheelectrical shut-off boxorcircuit breaker when thekiln is not in use, especiallyif you are concerned thatsomeone could turn it on

while you are away.

q Keep the kiln lid or doorclosedwhenthekilnisnotinuse. This keeps dust out ofthe kiln. Also, should some-one turnonthe kilnwhile you are away, the closedlid

will keep the heat safely inside the firing chamber.

q Never place anything on the kiln lid, even when thekiln is idle. If people become accustomed to placingpapers and other objects on the kiln, they may forgetand do that while the kiln is firing.

q Remove all tripping hazards from around the kiln.Keep the kilns supply cord out of traffic areas.

q Do not let the cord touch the side of the kiln; it be-comes hot enough to damage the cord.

q Avoid using extension cords.


Centering the clay has a way of putting meinto that altered state where time doesnt hap-pen.

Millie Carpenter


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q Wear gloves when youload and unload yourkiln. The gloves shouldbe thick enough to pro-tect you from glazeshards and bits of pyro-metric cones that havestuck to shelves, sharp

edges of broken ware,and sharp stilt marks onthe bottom of glazed

ware. Razor-sharp glazefragments can be sosmall that they are difficult to see.

q Do not remove the ware from the kiln until the kilnhas cooled to room temperature. It is possible forthermal shock to break hot ceramic pieces. Thesharp edges of broken ware can injure hands.

q After firing glazed ware in your kiln, examine theshelves for glaze particles. Sharp slivers of glaze

stuck to the shelf can cut hands. Before rubbing ahand over a shelf, be sure the shelf is free of glazeshards.

q Fire only approved materials purchased from aknowledgeable supplier. Do not fire marbles, piecesof concrete, rocks, and other objects. Rapid heatingto high temperature can cause violent reactions inmany materials.

q Avoid firing toxic materials such as moth balls insidethe kiln. Moth balls create toxic fumes inside a kilnand can even explode.

q Never fire tempered glass inside a kiln. It could ex-plode.

q Greenware, which is unfiredclay, must be bone dry be-fore firing. Moist greenwarecan explode inside the kiln,damaging the ware and thek i l n . P l a c e a p i e c e o fgreenware against the insideof your wrist. If it feels cool,it is too wet to fire.

q Do not fire cracked shelves. They can break duringfiring, damaging the ware inside the kiln.

q Storekilnshelves in a dry area. Moist shelves can ex-plode inside a kiln.

q If you smell burning plastic, turn the kiln off. Exam-ine the wall outlet and supply cord for signs of burn-ing.

q As the kiln fires, it is a good habit to place your handonthe kilns powercordto check the temperature.Itis okay if the cord is slightly warm, but it should

never feel hot. Make sure the plug is pushed all theway into the receptacle.

q Never place extrainsulation around the kiln in an at-tempt to conserve energy. The extra insulation cancause the switch box wiring to over-heat and thesteel case to warp.

q Do notwear loose-fitting clothingarounda hotkiln.

q Remove flammable materials from the kiln room. Ifyou fire a kiln in the garage, park your car outside.Remove the lawn mower, gasoline, and other flam-mable materials. Keep packing materials such asshredded newspapers out of the kiln room.

q Keep unsupervised children away.

q Keep a Class C fire extinguisher and a smoke alarmin the kiln room. Mount the extinguisher near thedoor to the room.

q Do not breathe brick dust, kiln wash, or kiln repaircement. Prolonged exposure may cause lung injury.

Vacuum the kiln with a HEPA filtered vacuumcleaner or a central vacuum that takes the dust out-side.

q Only vitrified ware should be used in a microwaveoven. (Vitrified clay has been fired to a point wheretheparticlesbecomeglass-like andno longerabsorb

water.) Non-vitrified clay such as earthenware isgenerally not suitable for microwave use, becausethe clay absorbs water. The water in the pores of theclay can expand rapidly enough in a microwave tocause the ware to crack or even explode. Ware thathas been decorated with metallic glazes should not

be used in a microwave oven.q Whenever you turn off the circuit breaker to your

kiln, tape the breaker box door shut and leave a notesaying, WORKING ON KILN. BREAKER OFF.


How to Avoid an Over-Fire

Suggestions by Mel Jacobson, Potter

Use an alarm clock. I use the old wind-upkind with a loud ringer. Set it for a certaintime, and make sure you follow the ring.Place a small battery-operated oven timer in

your pocket if you need extra reminders.Get a large bulldog clip and paint KILN inred. Clip it to your jacket, or hang it from adoorknob. Or place a sign where you hang

your apron: KILN ON.

When I was a high school teacher, I had thejanitorturnoffthemaster breaker to thekilneverynightat8.Nokilnwouldeverbeonpast7, ever, anyway.


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SETTING UPSetting Up The Stand

Operate your Paragon kiln only on the stand providedor on theoptional deluxe stand with casters. (Sometimespeople buy used kilns that are missing the original stand

and place the kiln on cinder blocks or bricks. This not agood idea, because bricks may inhibit the flow of air un-der the kiln. Cinder blocks or other supports could alsochange the kilns heating characteristics.)

Insert the mar-proof plastic tips on the standlegs.

Place two stand side pieces in front of you as inthe illustration. Place a stand leg inside the side

frame. Insert bolts, tighten nuts.Assemble the other corners the same way.

Position the stand on a concrete floor or a hightemperatureprotectivesheet.Thestandmust belevel to alleviate stress on the kiln during firingand to prevent glazed pieces from falling off thestilts.

To level, place a shim UNDER the appropriateleg or legs, not between the kiln bottom and thestand.

Center thekiln onthestandprovidingfor a mini-

mum of 12" clearance between the kiln and theclosest wall.

Make sure the kiln is sturdy on the stand. Tomove the kiln, lift it, dont push it. Pushing thekiln could collapse the stand.

Attach theLock-In LidSupport

Models with the lid support:Connect the lid support to thestud on the side of the kiln.

Tighten the lock nut until it issnug.

Where toLocate Your Kiln

In additionto these guidelines, pleaseseeSafe Instal-lation of the Electric Kiln, a separate publicationshipped with your kiln.s Plan your firing area near a present electrical outlet or

where a new circuit can easily be installed.

s Place your kiln in a well-ventilated, covered, and pro-tected area such as the garage, basement, storagebuilding, utility or ceramic hobby room.

Caution:The fumes fromware fired in a kilncancorrode metal and etch windows. If you are in-stallingyourkilnin a livingareasuchas the base-ment or in the garage, it should be vented with amotorized vent. Please see Safe Installation ofthe Electric Kiln.

Q Is itokaytoplace the kilnona covered porch orin a carport?

A Yes. As long as the kiln is protected from the

weather, it can be installed in a roofed-in areawith open sides such as a carport. But especiallyin humid areas, the kiln may rust faster than it

would inside an enclosed building.

s DoNOT storegasoline,paint,orother flammable liq-uids in the kiln room.

s Neverallow theroom temperatureof your firingroomto exceed 100- 110F. (Roomtemperatureis thetem-perature measured three or more feet away from thekiln.) If necessary, use is to move the heat away fromthe kilns switch box.

s Electrical components such as switches, the digitalcontroller,relays,andwiring last longerwhentheystaycool. The easiest way to lower the temperature of akilns switch box is to blow air into the side louvers

witha fan. Itdoesnot needtobea large fan; onewith4"- 8" diameter blades on low speed is effective. The airshouldgoinonesideoftheswitchboxandoutthelou-

versof the other side. Do notallow air to blow intothekiln through the peepholes or lid.

The legs go inside of the stand frame.


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s Provide a minimum of 12 clearancebetween the kilnand the closest wall.

s Never place the kiln near curtains or other combusti-ble materials such as art room supplies.

s Position the kiln stand on a level surface that will notbe damaged by heat. We recommend a cement floor.However, a sheet of protective material may be usedunder the stand. Consult your hardware or buildingsupply store for a recommendation.

s Avoid placingthekilnstandonrubber tile, linoleum orany surface that might tend to mar or discolor whenheated.

s Place the kiln in an area where it can be easily loadedand unloaded yet out of the way when not in use. Forconvenience in moving the kiln when not in use, con-sider the reinforced, deluxe stand with casters.

s Keepunsupervised childrenaway fromthe firingarea.

s Do not allow the kilns power supply cord to contactthe side of the kiln. This could burn the cord. Beforeeach firing, check all around the kiln to make surenothing is touching the kiln case.

Cold WeatherItis okayto store and firethe kilnin anunheated build-

ing during winter. But before operating, raise the tem-perature of the kilns switch box to at least 32F (0C)

with a space heater.

Q What is the difference in the cost to fire a kilnin a warm room compared to firing in a coldroom?

ARoom temperature has almost no effect on theelectrical cost of firing a kiln. However, if yourkiln is under a carport that has open sides, pro-tect the kiln from wind. Air blowing against thecase can raise the electrical cost slightly. If youuse a fan to lower the temperature of the switchbox, positionthe fan sothat the air blows into the

switch box louvers but not onto the firing cham-ber case.

Installing the Kiln in anInstitutional Setting

Sometimes maintenance employees are not familiarwith kilns. For this reason you might want to place a signon top of the kiln when the kiln is not in use:

Do not stand on the kiln.Do not move the kiln.Do not place anything on top.

(Reminder: Remove any signs from your kiln beforeyou fire it.)

Placeasignonthedoorofthekilnroom:KilnisFiring.Every year hold a short kiln orientation session for the

maintenance staff. You could also send the same infor-mation by e-mail to the school principal and the mainte-nance department. Explain the following:

The kiln is fragile.

During operation, the kiln makes a clicking noise.This is normal.

If you use a temperature alarm on your digital kiln,explain the beeping noise. Otherwise it willfrighten students and maintenance people be-cause they will assume that something is wrong.

Seating the ElementsShipping may dislodge the elements of your kiln.

Please performthekitchen knifetest to make sure theel-ements are seated in their grooves.

Kitchen Knife Test

Caution:Always unplug the kiln before touchingan element with anything.

Caution: Touch only a cold element, never a hotone, with a plastic object such as a comb. Plastic

will melt on and ruin a hot element.

Press the ele-ments into theirgrooves by running ablunt kitchen knife,plasticcomb, orsimi-lar blunt object com-pletely around each

groove. Do this be-fore the first firing,because it may not beevident to the eye

whether the coil is inits groove.

Note: Dont force the element into the groovecorners. If theelementwont fiteasily, lengthenit

with automotive snap-ring pliers (available fromauto partsstores). Stretch thespacebetween the


Lower the switch box temperature with air movement. This is especiallyuseful during hot summers.


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coils just a little wherethe element fits intothe wall brick corners.It should then easilyseat into the corners.

If the element doesntlie flat in the bottom of itsgroove, you neednt beconcerned as long as theelement fits all the wayback into each corner anddoesnt bulge outside thegroove. In fact, elementswill not lie flat in their ter-minal bricks (right behindswitch box).

Before the kiln is fired,the elements are mallea-ble; there is no danger ofbreaking the elements

whenyou bendthem. After

firing, however, the ele-ments become brittle andmust be reheated if theybulge out of the groove.See Reseating a BulgingElement, page 38.

Cleaning the KilnClean your kiln before

firing. Use a a vacuumcleaner (preferably with asoft brush nozzle) to re-

move brick dust from in-side the kiln, especiallyfrom the grooves. A dampclothor damp sponge mayalsobeusedtogentlywipedust from the sidewallsand brick bottom. Cleanthe kiln again whenever

you notice dust inside.

Note:Vacuum the kiln with a HEPA filtered vac-uum cleaner or a central vacuum that takes thedust outside. Keep the vacuum hose away fromthe controller on digital kilns.

THE ELECTRICCIRCUIT

Please have only a qualifiedelectrician install your kilncircuit in compliance with local codes. If you plan to usean existing circuit, have a qualified electrician check the

circuitandcomparethe wire and breakersizeswith thoseshown in the Paragon catalog and website. The circuitmust never be used by other appliances while the kiln isfiring.

Electrical ShutoffWe recommend an electrical

shutoff box near the kiln in addi-tion to having a circuit breaker atthe electrical panel. The shutoffbox is a must for direct-wiredkilns, which cant be unplugged

to disconnect the power. We rec-ommend disconnecting thepower whenthe kiln isnot inuse.If you unplug the kiln frequently,the spring tension on the wall outlet may eventually

weaken. The shutoff box disconnects the power withouthaving to unplug the kiln.

Note: The shutoff box is not needed for 120 voltkilns.

Circuit Breaker PanelInstall the kiln within 25' of the fuse or circuit breaker

panel. For every additional 50' from the panel, increasethe circuit wire size by one gauge.But do not place the kiln right in front of the electrical

panel. Keep the panel at least 3' - 4' away. Otherwise, thebreakers may trip more easily on a hot day. This is be-cause a circuit breaker is triggered by heat, and a nearbykiln can raise the temperature of the electrical panel.

Note: Do not use the circuit breaker to discon-nect the kiln. Frequently switching the circuitbreaker will weaken it. Instead, use a shutoff boxlocated near the kiln.

Circuit WireUse a circuit wiresize large enoughfor the wall recep-tacle amperage, even if the kiln amperage is less than the

wall receptacle amperage.

WARNING: Changing the cord plug onParagon kilns mayvoid your warranty.

Trying to save money on the circuit installation by us-ing a smaller diameter wire is not cost effective, becausethe thinner wire generates more heat than the thicker


Expanding coils with automotivesnap-ring pliers.

As shown here, new elements donot lie flat in a curved groove.

What is it about that meditative quiet whenkids are working with clay? I teach 3rd, 4th and5th graders in a very poor neighborhood, andeven the toughest 5th grader will let down hiscool and tough act for clay.

Grace Sheese


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wire. The heat means wasted electricity and sometimesslightly lower voltage.

Use copper wire.Donot allow anelectricianto use alu-minum wire on your new circuit. Aluminum terminalscorrode worse than copper and require greater installa-tion care. Avoid using extension cords.

The Paragon kiln catalog and website show recom-mended breaker and wire sizes for the circuit. (These

recommendations assume that the circuit is dedicated,which means that it powers only the kiln and no otherappliance.) Local codes supersede our catalog recom-mendations.

Youmay alreadyhave a heavy-amperage circuitconve-niently located where you will keep your kiln. But do notassume that the circuit is the correct size. Clothes dryercircuits are too small for most studio kilns. Even if youhave thecorrectwalloutlet, you shouldverify that thewireand breaker sizes are also correct.

Voltage Affects Firing TimeVoltage fluctuation can vary the firing time for a given

pyrometric cone from as little as one half to more thantwice the average time. If the voltage is too low, the kiln

will never reach full temperature. This can be correctedonly by having the utility company adjust the voltage.(However, 208 volts cannot be adjusted to 240 volts, and

vice versa.)

Check the ElectricalInstallation

Check the receptacle voltage with a voltmeter beforeplugging in your kiln. Measure between the two slots

where theflatbladesontheplug are inserted. Only aqualified person shouldperform this test, becauseimproper use of a voltme-ter can result in shock tothe user. The voltageshould measure within 10

volts of the kilns ratedvoltage.

Verify that the safetygrounding wire is properlyconnected in accordance

with the National ElectricCode (or equivalent foryour country). This can beproven only by visual in-spection of the receptacle

wiring. Sometimes circuitshave been installed byhomeowners with limitedelectrical experience.

PREPARINGTHE KILNKiln Features

Kiln FirebricksPremium, hand-selected insulating refractory bricksarelightweight,porous, andprecisioncutto fittightlyandstore heat in the walls, bottom, and lid. The form-fitted

jacket snuglyholds the bricks together. Because the fire-bricksstore heat soefficiently, thecostof electricityto firethekiln is surprisingly low. Kiln brick is extremely fragileand will chip easily; always handle your kiln and its brick

with care. Never let a shelf bump against the firebrick.Firebrick damage is not covered by warranty.

Note: Allow only trusted people to load and un-load your kiln. Beginners may not understandthat the firebricks are fragile.

The temperature required forceramics is well above the meltingpoint of most metals, and tremen-dous stresses aregenerated duringthe firing. The insulating fire-bricks expand and contract witheach firing. In time, cracks will ap-pear in the brick while the kiln iscold.Thisisnormaland will not af-fect your kilns operation.

Heating ElementsThe heating elements in your Paragon kiln are heavy

duty for long life. All high temperature, heavy duty ele-ments are quite brittle after being heated to a high tem-perature and will break if bent while cold. By heating to adull red glow with a propane torch, an element may bebent safely.

Neverallowglaze, glass,silica sand,kiln wash,orotherforeignmaterials totouchtheelementssincetheywillde-stroy the element when the kiln is fired.

PeepholesLarge peepholes (view ports),

tapered for a wide view withoutheat loss, are used for observing

the progress of your firing so youcan see when the pyrometric conesbend. Use at least one large coneon the shelf during every fir-ingeven in a digital kiln. With

venting as their secondary func-tion, peepholes allow oxygen to bedrawninto thekilnschamberand serveasanescape pas-sage for smoke and water vapor.

When looking through the peepholes, always wear fir-ingsafetyglasses,which areavailablefromParagon. They


Checkingthe voltage ofa wall outletin the Paragon factory.


10/48

protect your eyes from thebright glareof thefiringcham-ber and make it easier to seethe cones at high tempera-tures.

Peephole plugs are used tostop air from entering the kiln,not to prevent heat loss. It is

beneficial to have some air en-tering the kiln at all times, so itis not necessary that the plugsfit tightly.

You can leave the peepholeplugsoutforsomefirings. Thisimprovesoxygenationin-side the kiln. However, this may cause cold spots in thekiln,especially if thereareairdraftsin your firingroom.If

you leave the peephole plugs out, keep ware at least 3"from the peephole. If your ware develops problems fromcool air drafts, such as a glazed piece with a crazed spot,insert the peephole plugs after the kiln reaches 1000F(537C), or about half way through the firing. If you use a

motorized downdraft Orton Master Vent, keep peepholeplugs inserted and the lid closed all the way for the entirefiring.

Prop-R-Vent

Ceramic pieces release gases and water vapor duringfiring.Ventingallowsthese gases to escape.Paragons fallaway Prop-R-Vent is installed on the switch box of mosttop-loading kilns. The prop supports the lid in an openposition during the venting period. The Prop-R-Vent

vents the lid in two stages.Toclose the lid after venting, lift the lid handleaninch

to let theProp-R-Vent fall. Lowerthelid gently; warrantydoes not cover damage to the kiln or the ware due to adropped lid. For lusters and overglazes, engage theProp-R-Ventin itssecond position foradditional venting.Do not rush the cooling of your kiln with theProp-R-Vent. This can damage your ware.

Do not drop the lid. Some people touch the lid handlefor the first time to lower the lid from venting and dropthe lid because the handle is hot. Use a heat-resistantglove or a lid lifter (sold by Paragon) to lower the lid.


Monthly KilnMaintenance

Make sure the kiln is centered on the standand that the stand is stable. Check the areaaround the kiln and remove flammable ma-terials that have accumulated.

Vacuumthekilnwiththesoft brush nozzleofa vacuum. (Youcan use a hard plastic nozzleas longasyou dont touch the brickswith it.)Remember to vacuum the brick grooves. If

you have difficulty removing debris insidethegrooves, use a narrowwand-type vacuumcleaner nozzle being careful not to scrapethe brick walls. (Seepage 17.)

Vacuum around andunder thekiln: floor,shelves, and walls.This keeps the kilninterior cleaner andadds life to the op-tion vent motor.

Check the kiln washon shelves and kilnbottom for cracksandbarespotsin thecoating. Remove anyglaze drips. Reapplykiln wash if needed.(See page 19.)

Check the powercord and outlet forheat damage. Hasthe cord touchedthe side of the kiln during firing? This willdamage the cord insulation. Replace thecordsetorwall outletthatshows signs ofheatdamage.

Make sure elements are not bulging out ofthe grooves. Repair if necessary. (See page38.)

Kiln Downdraft Vent: Check the vent duct

for leaks. (See page 26.)Digital kilns: Make sure the thermocoupleextends far enough into kiln:

" diameter thermocouple: 1" into the kiln1

8" diameter thermocouple: 5 8" into the kiln

Wear f ir ing safety g lasseswhen looking through a peep-hole into a hot kiln.

Leave the lid closed ifyou have a motor izeddowndraft vent.

The Prop-R-Vent in theextended position.

The Prop-R-Vent in thefirst position.


11/48

Full-Formed SteelBase

Thegalvanizedsteel baseunder the brick bottomstrengthens the kiln. It cov-ers the entire bottom fromedge to edge.

The Lid SupportYour kilnhas either thelock-in l idsupport orthe LiteLidspring coun-ter-balance.Please do notle t un at-tended chil-dren raise thelid. Do not let the lid drop. It isfragileandmust beloweredgently.

Keep the kiln lid closed whenthe kiln is not in use. This keepsdust out of the kiln. Also, shouldsomeone turn on the kiln while you are away, the closedlid will keep the heat safely inside the firing chamber.

The LiteLid SupportBegin raising thelidusingthe center lid handle.

When the lid feelsweightless, hold a side lidhandle with your otherhand to guide the lid the

rest of the way up.

Donotletgoofthesidelidhandle unti l the l idreaches its fully openedposition. Otherwise thelid could slam upward,damaging the firebricksnear the hinge. (Pleasenote:This type of damageis not covered by war-ranty.)

Stay clear of the lid when

raising or lowering. Thisis to prevent injury shouldthe lid drop.

Dust-Free Refractory CoatingThe dark coating on the lid, the top rim of firebricks,

and in the peepholes reduces dust and hardens the fire-brick surface for longer life. Though it will lighten afterthe first firing, the coating will last for several years.

PYROMETRICCONES

Ceramists of early times judged when the fir-ing was completed by the

color of the kiln interiorand the length of firing. In1886, a German ceramistnamed Seger made claycones that bent when theceramic ware received theproperheat work.Heposi-tioned the cones on a shelfinside the kiln. By lookingthrough a peephole, he

could see the cones bend and knew when to turn off thekiln. His cones took the guesswork out of firing.

Todaywestilluse Segerscones. They arecalled pyro-

metric cones and are small pyramids of clay and mineraloxide that soften and bend when exposed to heat. Theyindicatewhen yourware hasfiredto maturity.When con-sulting your dealerwith a glaze problem, you should havea bent cone from that firing. The cone will help troubleshoot the problem. The cone lets you compare one firingto the next. Cones are manufactured by the Orton Ce-ramicFoundationandareavailablefromyour distributor.

Cone NumbersThe most confusing thing about cones is the way they

are numbered. They are easier to understand when youknow the reason behind the numbers. Pyrometric conesare numbered from 022 through 01 and 1 through 10.Cone 022 matures at thelowest temperature,and10 ma-tures at the highest.

Seger numberedhis originalcones from1 to20, with1being the lowest temperature.Later, cones of even lower temper-aturesthancone1 were needed.Toavoid changing all the cone num-bers, thenewnumbers startedwith0 and went from 01 to 022, withhigher numbers getting progres-sively cooler.

To avoidconfusion,mentally re-place the 0 with a minus sign.Numbers without the 0 are posi-tive. The higher the positive num-ber, the higher the temperature.

Numbers with the 0 (or a minus sign) are negative.Thehigher thenegative number, thelower thetempera-ture. With this in mind, you can quickly see thatcone5 ishotter than 05.

Note: Store boxes of cones in numerical orderfrom lowest to highest temperature so that you


Do not exert downward

pressure on the lid untilthe lock-in lid support iscompletely disengaged.

TheLiteLid springcan pinch fin-gers. Please keep unattendedchildren away from the kiln.

Donotletgo ofthesidelidhan-

dle until the lid reaches its fullyopened position.

A se lect ion of se lf -support ingcones. See the cone charts onpages 12 and 13 for a list of conecolors.


12/48

will be less likely to inadvertently pick up thewrong box.

The number is stamped on the base of the cone. Thecone number for each material is usually stated on thela-bel by the clay or glaze manufacturer. Your supplier canalso give you the cone number.

Heat WorkCones are rated by temperature. But it is more accu-ratetothinkofthemasmeasuringheatwork,nottemper-ature alone. Heat work is the combined effect of time,temperature, and the atmosphere inside the kiln. Allthese factors affect the maturityof your ware and not justtemperature. For instance, firing to a lower temperaturefor a longer time will produce the same maturity as firingto a higher temperature for a shorter time. The Tem-perature Equivalents chart (next column) shows that aself-supporting05 cone requiresa temperatureof1911Fto bend to 6 oclock, yet when fired slower, it will bend at1870F.

During the last 100 - 200 degrees of firing, the firingrate affects the bending temperature of a pyrometriccone. The faster the rate, the higher the temperature

whentheconebends. But the firing speed before the last100 - 200 degrees has no influence on the final tempera-ture of the pyrometric cone. The exception is an ex-tremely fast firing that bloats the cone.

Consult yoursupplierfortherecommendedfiringrateofyourclaysand glazes. Thethicker the clay, theslower itshould be fired. Firing clay is like making cookies in anoven. Heat the cookies fast, and theywillbebrown on theoutside but still gooey on the inside. Heat the cookiesslowly, and they will be brown all the way through.

Using ConesPlace the cones on a kiln shelf with the ware. As the

cones heat and bend, they form a glassymaterial that willstick to a bare shelf. Therefore, apply kiln wash to theshelves to prevent sticking. Do not apply kiln wash to thecones. (See page 19 for kiln wash.) The cones slant 8 de-grees from vertical and bend in the direction of the slant.They will not bend accurately if they are slanted at the

wrong angle. Position a cone so it will not touch nearbyware as it bends.

Large cones come in ei-ther standard or self-sup-porting. Standard largecones mustbe mounted in aclayor wireplaquewith 2" ofthe cone exposed above thecone holder. Or you canmount large cones ina pat ofclay. The clay should be drybefore firing. To speed dry-ing, make indentions in theclay with the end of a small


F Temperature Equivalents For OrtonSelf-Supporting Pyrometric Cones

ConeCone Self-Supporting Cones Pre-Fire

Number ColorHeated 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

011 1575 1607 1641 Orange

010 1636 1657 1679 Dark Red

09 1665 1688 1706 Dark Red

08 1692 1728 1753 Dark Red

07 1764 1789 1809 Dark Red

06 1798 1828 1855 Dark Red

05 1/2 1839 1859 1877 Dark Red

05 1870 1888 1911 Dark Red

04 1915 1945 1971 Dark Red

03 1960 1987 2019 Dark Red

02 1972 2016 2052 Dark Red

01 1999 2046 2080 Dark Red

1 2028 2079 2109 Dark Red

2 2034 2088 2127 Dark Red

3 2039 2106 2138 Dark Red

4 2086 2124 2161 Gray

5 2118 2167 2205 Green

5 1/2 2133 2197 2237 White

6 2165 2232 2269 Fuchsia

7 2194 2262 2295 Orange

8 2212 2280 2320 Yellow

9 2235 2300 2336 White

10 2284 2345 2381 Pink

*Rate of temperature increase during last 90 -120 minutes of firing. Tablesbycourtesyof the Ed-

ward Orton, Jr. Ceramic Foundation.

Standard largeconesin clay conepacks.


13/48

brush handle after the cone is inserted. Self-supportingcones stand upright without holders. We recommendself-supporting cones; they are easier and faster to usethan standard large cones.

Handle cones carefully. They are fragile because theyareunfired clay. If dropped, they maydevelop cracks thatcould affect their performance.Ageandnormal humiditydo not affect the accuracy of cones. Even if a box of cones

is 20 years old, you can stilluse them. However, do notusethemiftheybecomewet.

Standard pyrometriccones comein two lengths:11

8" and 2 ". The small coneis used in the KilnSitterandthe large cone is used on thekiln shelf.

Note: The Kiln Sitter isa mechanical shut-offdevice that is triggeredby the bending of a

small cone. Digital con-trollers do not use thesmall Kiln Sitter cone.

Self-supportingcones are2 3

8" long. They are packaged

as sets of double cones sothat they will be less fragilein shipping. You will need toseparate the cones. Hold thelarge section of the cones

with the thumb and forefin-ger of each hand and twist.They will snap apart.

Check the accuracy ofyour Kiln Sitter or digitalcontroller by placing cones on the shelf. Mount behindeach peephole a large cone of the same number you arefiring to. This is the firing cone. Next to the firing coneplace a large cone of the next lower temperature; this isthe guard cone. For example, if you are firing to cone 05,place large cones 05and 06 onthe shelf behindthe peep-holes. We recommend at least one large shelf cone in ev-ery firing.

Place large cones on the shelf at least 3" away from apeephole. This is to avoid cool air drafts.

Always use Paragon firing safety glasses when lookinginto the peepholes. These glasses are specially coated tofilter out the infra-red and ultra-violet light inside a kiln.They also protect your eyes from heat and reduce glare,making the pyrometric cones easier to see.


C Temperature EquivalentsFor Orton Self-Supporting

Pyrometric ConesCone Self-Supporting Cones Pre-Fire

Number ColorHeated at: 15 C 60 C 150 C

Per Hour* Per Hour* Per Hour*

022 586 590 Green021 600 617 Fuschia

020 626 638 Orange

019 656 678 695 Yellow

018 686 715 734 White

017 705 738 763 Pink

016 742 772 796 Light Blue

015 750 791 818 Violet

014 757 807 838 Gray

013 807 837 861 Green

012 843 861 882 Fuschia

011 857 875 894 Orange

010 891 903 915 Dark Red

09 907 920 930 Dark Red

08 922 942 956 Dark Red

07 962 976 987 Dark Red

06 981 998 1013 Dark Red

05 1/2 1004 1015 1025 Dark Red

05 1021 1031 1044 Dark Red

04 1046 1063 1077 Dark Red

03 1071 1086 1104 Dark Red

02 1078 1102 1122 Dark Red

01 1093 1119 1138 Dark Red

1 1109 1137 1154 Dark Red

2 1112 1142 1164 Dark Red

3 1115 1152 1170 Dark Red

4 1141 1162 1183 Gray

5 1159 1186 1207 Green

5 1/2 1167 1203 1225 White

6 1185 1222 1243 Fuchsia

7 1201 1239 1257 Orange

8 1211 1249 1271 Yellow

9 1224 1260 1280 White

10 1251 1285 1305 Pink

*Rate of temperature increase during last 90 -120 minutes of firing. Tables bycourtesyof the Ed-

ward Orton, Jr. Ceramic Foundation.

A self-supporting cone next to asmall Kiln Sitter cone.

Separate the cones with thumbpressure.


14/48

How to PositionConeson the Shelf

Position the witness cones so that you can see them

through a peephole during firing. If the kiln takes longerthan usual to fire, you may wonder if something has gonewrong andthekilnis over-firing.Butbyseeing thecones,you will know how the firing is actually progressing.

Ifyoufollowtheseguidelines,you should beable toseethe cones even at cone 10:

Place the cones 8"- 12" awayfrom a peephole. Po-sitioning them closermakesthem difficult to seeand may also subject them to cool air drafts.

Note: Keep cones at least 2" from an element.

Have enough spacearound the cones to

k ee p t hem fr omtouching a piece ofware when they bend.

Position cones so thatwhen viewed from thepeephole, they are sil-houetted by an ele-ment on the oppositekiln wall. If the size of

your ware doesnt per-

mit placing a shelf atpeephole level,use a post toraise the cones.

Theelementthatsilhouettesthecones shouldbelevel with the lower part of the cone. If the ele-ment is in line with the upper part of the cone,theconewilldisappear from view whenitbends.

Note: The center ele-

ments in some kilnmodels do not glowbrightly even at hightemperatures. In thiscase, position the wit-ness cones level with atopor bottom element.The element mustglow brightlyto silhou-ette the cones.

If youuse thethree-cone system,always have thehigher temperature coneon the same side in every

firing. Otherwise you canlose track of which cone is

which.

Wear kiln firing safetyglasses when viewing thecones through the peep-hole.

Note: You may find it easiertosee the cones byholding asmall mirrorata 45 angle infront of the peephole. You

will still need firing safety

glasses.

Caution:Some ceramistsblow into thepeepholetomomentarily darkenthe conesotheycan see itbetter. Pleasedo not do this. This can blowbrickdustonto the wareand isa safetyhazard. Coolairalso changes the temperature at which the conebends.

Caution: Some ceramists coat the witness coneswith red iron oxide to make them easier to see.Avoid this. It changes the temperature at which

the cone bends.


A same cone silhouetted by a heat-ing element a t cone 72262F(1239C).

A cone seen through a peepholewhile the kiln is at room tempera-ture.

Line up the heating element with the lower part of the cones.

Thetop andbottom elements glowbrighterthan thecenter elementsinsome kilns.

Wear firing safety glasses when viewing a witness cone.

Working in my small studiokeeps me sane and happy. I for-get abouteverything elseand amgrateful to do what I do.

Heidrun Schmid


15/48

Using Cones inDigital Kilns

Although the digital controllers do not need cones tooperate, we recommend them anyway. Place at least oneself-supporting cone on a shelf behind a peephole in ev-ery firing.

If thebending of thewitness cones varies slightly fromfiring to firing, you need not be concerned. Slight varia-tions in the bending of the cone are normal and may bedue to the location of the cones on the shelf, the distance

of the cones from ceramic ware, and even variations incones frombox to box. This normalvariation willhavenoeffect on your ware.

Ifyourdigital kiln shutsoffbeforethe largeconeontheshelf bends and youre there when it happens, programthe controller to a higher temperature oradd a hold. (Seethe separate digital controller manual for your kiln.)Then turn the kiln back on.

Q When a kiln is taking longer than usual tocom-plete a firing, how do you know whether some-thinghas gonewrongand thekilnisover-firing?

AYou should place pyrometric witness cones onthe shelf so that you can see them through apeephole.

Heres another way to

help prevent an over-fire:Learnto estimatekiln tem-perature by the color oflight showing around thelid and peepholes. That

way, you can tell at a glanceif all is well with your kiln

when you check it.

Q Is it okay to use oldcones?

AYes. Age does not af-fect the cones.

Q Do you need to lookat witness cones dur-ing a firingor onlyafterthe kiln has cooled?

A Position the cones so that you can see themthrough a peephole. Form the habit of looking atthe cones near the expected shutoff time espe-cially if thefiringistakinglongerthanexpected.


The Bendingof the Cone

You can watch the cones as they bend. If youwant to slow down the bending for greater con-trol, add a digital temperature hold near the endof the firing. (See the separate controller man-ual.)

The large standard and self-supporting wit-ness cones have reached maturity when the tipbends to the 6 oclock position.

Large standard cone: The tip should bendstraight down until it just begins to touch thecone holder.

Self-supporting cone: The self-supportingcone should bend downward until the tip is even

with the top of the base. The tip should be about" abovetheshelf surface. If theself-supportingcone tip touches the shelf, the cone is over-fired

by a few degrees of temperature.

Self-supporting cones: Left, over-fired or puddled; Center,fired to maturity; Right, under-fired.

The light around the edgeof the lidand inside the peephole changescolor as the kiln gets hotter. Youcan learn to estimate temperatureby the color of that light.

My grandmother, who has taught chinapaintingfor60years, coached meduringmyfirst

firing. I treasure the memory of that moment ofmy life with her.Darcy Giesseman

When I couldnt get my first little half poundball of clay to center, my teacher kneeled downbesidemywheel,waitedfor metostop, and said,Hey, its just mud. Dont let it control you. Youcontrol it. When I have a problem, especially

with centering, I just zone out with my hands inposition on the clay, relax my shoulders, and tell

myself, Its just mud. And the clay obeys.Sheron Roberts

I love the impossibility of ceramics. Justwhen I think Ive got it figured out, somethingbursts my bubble once again. It keeps me hum-ble. It keeps me interested, challenged, en-thralled.

Kelley Webb Randel


16/48


17/48

Tile and Plate SettersThese are holders used to

stack plates and tiles insidethe kiln. Firing plates andtiles is more efficient with atile orplatesetterthan placingthese items flat on the shelf.The setters not only save

spaceinthekilnbut also allowair circulation around theware, preventing warping andbreakage. The ware heatsmore uniformly in a setterthan when placed directlyonto a kiln shelf.

Bead RodsCeramic greenware

beads can be piledonto the kiln shelf. Butonce the beads havebeen bisque-fired andthen glazed, they mustbe suspended by stiltrods (also called beadrods). Since the beadsareglazedallover,theycannot be placed on the kiln shelf. Stilt rods are madefrom the same type of wire as kiln heating elementsthough the rods are thicker than elements.

The beads must not be glazed inside the hole andaround the edge of the hole. Otherwise they will stick tothe rod. Space the beads so they do not touch. Suspendthe stilt rods between two posts.

All Purpose, HighFire Kiln Wash

High fire kiln wash is amixture of finely groundminerals that do not fuseatporcelain and stonewaretemperatures. It acts as abarrier between the shelfand dripping glaze. Thekiln shelf must be coated

with kiln wash to keep ce-ramic glaze and glass fromsticking to it. Without a barrier, the glaze would embed

permanently into the shelf.Caution: Contact with kiln wash will destroyheating elements.

Brush kiln wash on the tops of kiln shelves and on thekiln bottom to prevent glaze drippings from stickingper-manently to these surfaces. As a powder, high fire kiln

wash has an unlimited shelf life. (See page 19.)

PREPARING TOFIRE THE KILN

Vacuuming the KilnNote:Donotbreathe brickdust. Vacuum the kiln

witha HEPA filtered vacuum cleaneror a centralvacuum that takes the dust outside.

One of theeasiestkiln maintenancetasks youcanper-formisregularvacuuming.This isespecially important if

you fireglazes.Vacuum the kiln before every glaze firing.This helps to pre-

vent dust particlesfrom landing onglazed ware duringfiring. Vacuum ev-ery four bisquefirings.

U se t he s of tbrush nozzle on avacuum cleaner. Besure to vacuum theelement grooves,the inner surface ofthe kiln lid or roof,and the underside of kiln shelves.

Vacuuming the element grooves may extend elementlife by removing brick dust that settles in the bottom ofthe grooves. Vacuuming the grooves is essential if any-thing has exploded inside the kiln. Pieces of greenwarethat lodge inside the grooves can burn out an element.

Note: Over time, brick dust may accumulate inthe bottom of the element grooves. This can in-terfere with heat transfer from the elements andactually slow down the firings.

Vacuum the kiln often if you use silica sand on theshelves. The sand, which is used to support ware duringfiring, can ruin the elements if it filters down into an ele-ment groove.

As you vacuum the kiln, examine the walls for glass orglaze particles that have embedded into the firebricks.Dig these outcarefully with a screwdriver. Otherwise theparticles will embed deeper into the firebrick during the

next firing.Digital kilns:A staticelectricchargemaybuild uponthevacuumhose especially in dryweather.Staticelectric-ity can damage electronics. Disconnect the power to thekiln before vacuuming. Keep the vacuum away from thedigital controller, the switch box, and the thermocoupletip that extends into the firing chamber.


Separatethe glazedbeadsso they donotstick together on the bead rod.

Tile setters conserve space in-side the kiln when firing tiles.

Kiln wash protects shelves and thekilns brickbottom from dropsof hotglaze.

If youvacuum with a plastic nozzle, donotletthe nozzle touch the fragile firebricks.


18/48

Drying GreenwareOrdinarily, do not use the kiln to dry greenware. The

mostexpensive way to dry greenware is to heat it ina kiln.The moisture in the clay rusts the kiln, wears out ele-mentsfaster, wastes electricity, andif firedtoorapidly cancause the ware to explode. Moisture trapped in the clayexpands tremendously at the boiling temperature of

water.Note: If the ware explodes inside the kiln, let thekiln cool to room temperature.Then vacuum theinterior.

Wet clay contains about 30% water by weight. Duringfiring, moisture from the greenware turns to steam. Asthe temperature rises and the heated air in the kiln ex-pands, moistureescapesbypushingits wayintotheporesof the firebricks. When the moisture reaches the coolerstainless kiln case and galvanized steel base plate, it con-denses, causing water to drip around the kiln.

The firebricks in a typical 8-sided kiln can absorb ap-

proximately 50 pounds of moisture from wet greenware.This reduces the insulating capacity of the firebrick. Italso takes a tremendous amount of electricpower to con-

vert water to steam during firing. This slows the kiln to acrawl.

Ifyour kiln hasbeendrippingwater, fire thekilnemptyovernight onlow heat toburnoff the moisture in the fire-bricks.

Anefficientwayto drygreenware is to place it insideanenclosure such as a metal cabinet that contains a smallelectric heater. This is called a hot box. The moisture inthe clay raises the humidity inside the cabinet. The hu-midity keeps the clay surface moist, which prevents the

surface from closing upandtrapping moisture inside theware. Thus, the humidityallows the clay to dry evenly. Asthe clay continues to dry and moisture slowly leaves thecabinet, the humidity drops, which causes the clay tofinish drying.

The following suggestions will help you determinewhen the greenware is dry and what to do if it wont drycompletely:

Give the greenware enough time to dry. Dryingtime depends on the thickness of the clay, themethodofdrying,andthehumidityinyourarea.

Touch the greenware to the inside of your wristor toyourcheek. If it

feelswarm, it isusu-ally dry. Be sure tocheck the bottom ofa piece, which re-tains moisture lon-ger than the upper,thinner sections.Dry longer if the clayfeels cool or if it hasdark patches, which

indicate moisture. Note, however, that in humidareas, even damp greenware can feel warm.Greenware feels cool due to evaporation. Dampgreenware can feel warm when themoisturein itstops evaporating.

If the greenware is still some-what moist after an extendeddrying period or you are under

a tight deadline, load thegreenware into the kiln. Propthe lidwith the Prop-R-Vent inthe extended position andleave out the peephole plugs.Fire to 200F (93C) slowly.Maintain 200F (93C) untilthe greenware is completelydry.

Note: If you have a downdraftkiln vent, you canleave theventonduring preheat

with the lid closed and peephole plugs inserted.The vent will help to remove moisture.

Electronic kilns: Use the Preheat feature inCone-Firemode, orprograma200F(93C)preheatseg-ment in Ramp-Hold mode.

Manual fire kilns: Turn the bottom switch on low;leave the other switches off. (The switch setting variesdepending on the size of the kiln.)

Candling means firing the kiln at 200F (93C) orlower until moisture in the ware has evaporated. If youleave the lid well vented or leave a downdraft vent turnedonduringcandling, you cangetawaywith usingthekiln todrythe ware.But youwill probably increase the corrosionofsteelpartsinthekiln especially ifmoisture isstillin the

ware as the temperature goes up past the candlingtemperature.

Note: Bisque ware has already been through thebisquefiring, so itdoesnot havethe dryingprob-lems of greenware. Nevertheless, after applyingglaze to bisque, allow the glaze to dry before fir-ing. This usually takes a few hours.

Checking for Dryness with a MirrorHold a mirror above the lid or top peepholewhere hot

air from the kiln will move across the mirrors surface. Ifthe mirror fogs, thegreenware is still releas-

ing moisture. Keep thelid propped and main-tain 200F (93C) in thekiln until the mirror nolonger fogs. (If you arefiring with a downdraftkilnvent, you willneed toremove a peephole plugorpropthelidtoperformthe mirror test.)


Greenwarethat feelscool against thewrist still contains moisture.

T he P ro p- R- Ve nt i sshown here in the ex-tended position.

Moisture condenses on a mirror heldnear the peephole or the vented lid.


19/48

Note:The first timeyou fire the kiln, water in thefirebricks may fog the mirror for an extendedperiod.

For this test towork, the mirrormustbeatroomtem-perature. The mirror fogs when moisture in the hot aircondenses onthecoolermirror. Ifyouholdthe mirrortoolongnear the kiln, the mirrorwillheatupand will no lon-gerfogwhenmoisturehitsit.Soholditatthelidforonlyamoment at a time.

Note: You can dry the greenware by placing itaround the kiln during a firing. This uses heatfrom the kiln that otherwise would be wasted.

You can place the greenware on metal shelves orrollawaymetal tables. Becareful if you placewaredirectly onto the lid of a kiln. Too much weightcan crack the lid.

Shelf PreparationHigh Fire Kiln Wash

Kiln wash prevents glaze and glass from sticking per-manently to the kiln shelf and firebrick kiln bottom.Brush kiln wash on the tops of kiln shelves and on thekilns firebrick bottom.

Caution: Do not apply kiln wash to the kiln wallsor lid, theundersideof shelves, ortheposts.Con-tact with kiln wash will destroyheating elements.

Wear a respirator to avoid breathing kiln washdust.

Never use a low-fire ceramic type kiln wash, becauseafter firing the kiln above cone 04, the ceramic kiln wash

will harden and be difficult, if not impossible, to remove

later when you want to fire to hotter temperatures. Allpurpose, high fire kiln wash MUST be used in all kilnsrated to 2300F (1260C), even though the kiln is usuallyfired at lower temperatures.

Note: When unloading the kiln, move away fromthe kilnbeforewipingoff kilnwashfromthe bot-tom of the pieces. If you wipe off the kiln wash

while holding the pieces above the kiln, the dustcan settle into an element groove and destroy anelement.

How to Use Kiln WashPour a little water

into a disposablecontainer andadd powderedkiln wash until ithas the consis-tency of coffeecream. Stir untillumps dissolve.

Use a haik brush(available from

Paragon) or a soft paint brush to apply the kilnwash to the shelf. (The haik brush lays down aneven coating.) Each time you dip your brush intothe kiln wash mixture, swirl the brush around thebottom of the container. This is because the kiln

wash settles quickly.

Note: Start the brush stroke an inch or so fromthe edge of the shelf and work toward the oppo-

siteside. Thisis toavoidabuildupofkiln washonthe edges.

Apply twoor three thincoats of kilnwash changingthe direction of the brush stroke 90 with eachcoat. Let the kiln wash dry for a few minutes be-tween coats. Do not apply thick coats; they tend toflake off.

Removeany buildupofkiln washfrom theedgesofthe shelf by tracing around it with a finger. Excesskiln wash may break off the edges and fall onto

ware positioned below the shelf. Dry the shelvescompletely before firing.

Brush kiln washonto the ki lnbottom. Protectthe kiln wallsand elementsfrom kiln wash

with a piece ofc a r d b o a r d .Never apply kiln

wash to kilnwalls or to theunders ide ofshelves.

Let the kiln wash dry overnight. You can speeddrying byplacing shelvesin thekiln and heating toaround 200F (93C) for an hour. Thekiln-washed shelvesarestillwet if they feel cool tothe touch.

Note: Do not ap-ply kiln wash topyrometriccones.Kiln washchanges the ma-turing tempera-ture of the cone.

Note: If glaze orglass sticks to theshelf, scrape it off

with a putty knifeata sharpangle.Wearsafetyglassessometimeschipped glaze becomes airborne. Then recoatthe bare spot with more kiln wash.


Applying kiln wash with a haik brush.

Protect the elements when you apply kilnwash to the brick bottom.

Use a putty knife to remove flaking orcracked kiln wash.


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Q I have applied kiln wash tomyshelves. ShouldIalso kiln wash the underside of the lid?

AKiln wash should never be applied to the lid orwalls of thekiln, because it could flake offandfallinto an element groove or onto glazed ware. It isespecially important to keep the kiln wash awayfrom elements.

Q Thekilnwashisflakingoff some ofmyshelves.

A If the kilnwashis flakingfrom theshelves, youmay be apply-ingittoothick.Remove thekiln wash andapply a newcoat.

Recoating a

Shelf with Kiln WashWhenrecoating a shelf,removemostof theoldcoating

with grit cloth (available from Paragon). This is an abra-sive-coated mesh that allows residue to pass through.

You could also use coarse sand paper. Removing the oldcoating gives you a smooth surface to start with. Wear arespirator when removing kiln wash. Then recoat theshelf using the directions on page 19.

Kiln wash will usually last for many firings. When thekiln wash begins to crack or chip, apply a fresh coat.Scrape glaze drops off the shelves or dig them out of thebrick bottom as soon as they appear. Then apply a newcoat of kiln wash to the bare area.

100 Mesh Alumina Hydrate SandShelves can become warped at stoneware and porce-

laintemperatures. Large, flat stoneware pieces placeddi-rectly onto a warped shelf become warped at high tem-peratures. But there is a way around this: Place the wareover a layer of alumina hydrate that has been sprinkledonto the shelf. The sand evens out the warped surface sothebottomofthewareremains flatduring firing. Inaddi-tion, aluminahydrateactsas miniatureball bearings toal-low the clay to move as it shrinks during firing and helpsto separate the ware fromthe shelf for moreeven heatingof the piece. You can use the alumina hydrate over and

over. It is available from pottery supply distributors.Note:Wedonotrecommend thesilicasand avail-able from home improvement centers as a sub-stitute for aluminahydrate unless you first test it.If the sand contains iron particles, it will stick tothe ware.

Caution: Do not breathe alumina hydrate dust.Wear a respirator.

How to Use Alumina Hydrate

Note: If you use a fan to lower the firing roomtemperature, do not aim the fan directly at thekiln. The breeze can stir the sand (alumina hy-drate) inside the kiln. This could ruin glazedpieces and scatter sand into theelement grooves.It isokaytouse a downdraftkiln ventsuchastheOrton Vent Master. When correctly installed, the

vent does not create enough airflow to stir updust inside the kiln.

Donot placesandonthekilns brickbottom. Useit only on the shelves. The sand can work its waybetween the firebricks. Pour the sand onto theshelf beforeloweringtheshelf into thekiln. Ifyoupour the sand on the shelf inside the kiln, dustparticles are more apt to float inside the firingchamber, scattering onto your pieces.

Do not pour the sand onto the shelf from a largebag. Use a scoop instead. A scoop stirs up lessdust. After you have poured the sand onto the

shelf, a small ruler is helpful in spreading thesand.

Use the sand sparingly on the shelf for mostpro-jects.Usea thickerlayerunder thewareif youareconcerned about glazes running.

Keep the sand 2" - 3" away from the edges of theshelf. If the sand falls off the edges, it may filterdown into the element grooves or onto glazed

wareontheshelf below.Thisis especially impor-tant with half shelves.

As youlower the shelf intothekiln, hold theshelflevel. If it tilts, the sand could fall off the edges.

When unloading the kiln, remove the shelf andthe ware together. If the ware is too heavy to liftout with the shelf, then hold each piece of wareaway from the kiln before rubbing the sand off


You can also remove loose kiln wash with gritcloth and then apply a new coat.


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the bottom of the piece. If you hold the ware overthe shelf asthe sandfalls fromthe piece, the parti-cles could fall into an element groove.

Pour the alumina hydrate from the shelf into astorage container. Use a wide-mouth containerthatwill catch the sandas you tilt the shelf. A plas-tic container with lid works well. Save the sand forfuture firings.

Vacuum thekilnafter every firing witha soft brushattachment. Be sure to vacuum the elementgrooves.

Removing Glaze from the ShelvesPlace theshelf ona softsurfacesuchasa thinsheetof Styrofoam.

Wearing a dust maskand safety glasses, gently tapthe glaze drippings at a sharp angle with a puttyknife.

LOADINGTHE KILNHow to Store Kiln Furniture

Store kiln furniture in a dry area. Moist shelves can

crack or even explode inside the kiln. A freshlykiln-washed shelf should be allowed to dry thoroughly,then fired slowly to allow any moisture in the shelf toevaporate.

There is less danger of cracking if you store shelvesvertically in a shelf rack or even leaning against a wallrather than flat. If a piece of clay or other material lodgesbetween horizontally stacked shelves, weight pressingdown can crack a shelf. (However, as long as the stack isno higher than three or four shelves and the shelves areclean, you can store them flat, too.)

Store shelves sothatthe sides with kilnwashfaceeachother.This prevents flakes ofkiln washfrom transferring

to the underside of other shelves.Store posts of the same length together.Ifa shelf cracks, break itapart atthe cracksand use the

pieces as smaller shelves.

Note:You may find it helpful to draw a shelf pat-ternona table and plantheloadfor eachshelfbe-fore you begin loading the kiln.

Guidelines forLoading the Kiln

Loading a kiln is like putting together a jigsaw puzzle.

You may find it the most interesting aspect of firing, be-cause it requires thought and planning.

How To Handle Kiln ShelvesOne of the secrets to keeping your kiln in good condi-

tion is in the way you hold the shelves when you load orunload the kiln:

Check each shelffor cracks.

Work slowly andcarefully. Treat thekiln as if it were apiece of fine furni-ture that you didnt

want to scratch.Dont touch thefirebrick walls if youcan help it. Touch-ing the walls will cause dust to fall onto glazed

ware.

Tilt the shelf asyou lower it into the kiln. Center itso it doesnt touch the kiln walls. At all times, beaware of the location of the thermocouple or Kiln


Hold the putty knife at a sharp angle to remove glaze from a shelf.

Do not let the shelf touch the walls.

When you concentrate on making a pot, youhavenotimetodwell onyourproblems. I know atherapist who used clay in working with suicidalteens. She hasworkedwonders with these kids.

Mike Gordon

The profound experience of working withclay is to have a three dimensional image in your

head, and then have it come out through yourhands.Marie Gibbons

Many ofour customers, inverystressful jobs,find release through clay. One, a doctor, foundclay to be the road back from a mental break-down.

Stephen Mills


22/48

Sitter tube so that you avoid bumping the shelfagainst it.

As youlevel theshelf intoposition, center it in thefiring chamber. Top-loading kilns: Position

your hands so that they are at the firebrick cor-ners. This offers more space than straight sec-tions of the walls.

Iffullshelvesaretooheavyforyoutoload,usehalfshelves. Not only are they lighter, but they arealsolessapt totouchthewalls during loading andunloading.

Do not jar the kiln after loading, or the ware or ashelfcould fallover and break.Shelves should be1 - 2 smaller than the firing chamber.

Do not allow anyone to load or unload your kilnuntil you have trained them.

The Basics of LoadingDisconnect the power before loading the kiln.

Hang a portable light from the kilns lid handle if yourroom is poorly lit.Before loading the kiln, be sure all the ware is rated to

thesamepyrometriccone.Low-fire warefiredwith a loadof stoneware could melt into a puddle, ruining kilnshelves.

Avoid back strain. When possi-ble, load empty tile setters into thekiln. Then add the tiles to the set-ters that are already in position.This is easier than lifting fullyloaded tile setters into the kiln.

Ordinarily, load pieces of me-

dium height on the bottom shelfand tall pieces on the top shelf.This improves the stability ofposts since short posts in the bottom of the kiln are morestable than tall ones. But if you have difficulty reachingdown into a deep kiln, leave the bottom shelf in place andload tall pieces onto it. A short stepladder or concreteblock is an aid to reaching into a deep kiln.

We urge the use of at least one large pyrometric conebehind the peephole on a kiln shelf in every firing. Placecones 8 - 12 from the peephole. (The minimum dis-tance between the cone and a peephole is 3. This is topreventexposuretocoolair.)Check theconethroughthepeephole before placing a shelf over it.

L ar ge , h ea vy greenware pieces

willfirebest if placedacros s two h al fshelves positioned atan even height.

After loading thekiln, close the lidgently. Jarring the lid

will not only damage

it but will also cause dust to fall onto glazed ware on thetop shelf.

Loading for EfficiencyTo make full use of

your kilns firing capac-ity, group similar sizesof ware together insidethe kiln. (Begin group-ing similar sized wareas you lay the pieces outto dry prior to firing.)Fill empty areas of theshelf with small piecessuch as medallions.They make good glazetesting samples that

you can sell or giveawaylater.

Stack ware on half shelves to take advantage of blankspace next to tall pieces.

When firing pieces of varying heights on the sameshelf, the tall pieces should go in the center. This is toavoid blocking radiant heat from reaching the shorterpieces.

To save space during thelow-fire ceramic or stone-

ware bisque firing, you canplace bisque ware withinother larger pieces. The

ware shrinks during firing,sopieces thatare stacked to-gether must have shrinkage room. Otherwise they willcrack.

Placesmall, lightgreenwarepiecesdirectlyon thefloorof the kiln. Leave ample room for air to circulate aroundtheir bases since this area is difficult to heat.

A good place for tall pieces is the top shelf, with noposts or shelves above them.

DistancesInsidethe Kiln

Keepwareat least 1"away from a heatingelement. Glazes maybubbleand land on an el-ement if the ware is tooclose. If you fire a piecethatissolargethatatipofit comes closer than 1 toa kiln wall, place thatsec-tion of the piece betweenelement grooves and notdirectly opposite an ele-ment.


Large greenware pieces can be fi redacross two half shelves.

Use half shelves to load layers of warenext to tall pieces.

Keep ware at least 1 away from theelements. If ware extends closer than1 to a wall, place it between rows ofelements.


23/48

T he m i ni m ums paci n g b e twe e nshelves is 2 ". Youcan achieve this mini-mum 2 " height bystacking a " post ontop of a 2" post. Shelvesmust be stacked so

there isat least one rowof heatingelementsbe-tween any two shelves.

The posts usedwith each layer ofware should be atleast1" taller than the

ware. Keep a rulernear your kiln. As youfill a shelf with ware, laythe ruler across two

posts or the top of thekiln to make sure theware is not too tall.

Keep all ware andkiln shelves at least1 " away f r o m th eside, top, and bottomof the end of the KilnSitter tube or digitalthermocouple. If thekiln is nudged duringfiring and the shelvesmomentarilyshift posi-tion, the Kiln Sitter orthermocouple couldmalfunction.

Make sure at leastone element grooveis between the topshelf and the top ofyour kiln. The top of

ware should be at least1" lower than the lid. Ifthe ware on your topshelf is over- or un-der-firing,tryusingtwohalf shelves instead of afull shelf. Stagger theheight of the shelves.

Glazed WareAs you load each shelf into the kiln for a glaze firing,

wipeofforvacuumdust fromthe undersideoftheshelf.Lowerthelid gently.Rough handling will crack the lid.

This may result in dust falling from the cracks ontoglazed ware on the top shelf. If your lid is cracked, load

smalleritemson the topshelf leaving a blank spaceon theshelf under the lid crack.

Separate glazed ware by ". If pieces are placed tooclose together, a glaze of one color may contaminate theglaze of a different color on the next piece.

Do not wipe dried glaze drips from the ware while youare standing over the kiln. The glaze particles may fallinto the kiln and land in an element grooveor fall into the

louver of a switch box. This could cause an element toburn out or a wire connection to fail.Some glazes tend to run off the ware and onto the

shelf. In the worst cases, the running glaze eats throughthe kiln washand embeds into the shelf. You can preventthis byplacingbrokenpieces ofkiln shelf underthe ware.The shelf piece will catch the glaze. Orroll out a " thicklayerofclay,cutitintocircleswithacan(similartousingacookie cutter), and coat the claywith kiln wash. Place theround coaster under the ware to protect the shelf.

Forkilns with a downdraftventsuchasthe OrtonMas-ter Vent, donot loadglazedwaredirectlyunder the air in-take holes in the lid.

Ware that is prone to warping, such as ware with thinwalls or flared tops or large bowls, should be placed awayfrom the elements. The bottom of ware that extends outpast the edge of a shelf may warp.

Pieces that go together, such as matching cups andsaucers, should be placed next to each other on the kilnshelf. This helps assure uniformity in glaze color. Tokeep holes inglazed saltandpeppershakers from closingin with glaze, insert tooth pick pieces in the holes. They

will burn away during the firing.

Heat Distribution

Inside the KilnYou may remember from early science class that heatrises. This is called convection. Kilns tend to fire cooleron the bottom, but not because heat rises. Movement ofheat through convection ends at around 1100F (593C).

At1700F(926C), airhasonlyabout one-tenth thenum-ber of molecules as at room temperature. This is whythere is little airflow in an electric kiln at hightemperatures.

The bottom and top tend to stay cooler because thebrickbottom andlid arelarge thermal massesthat absorbenergy. Paragon compensatesforthis by makingthebot-tom and top elements fire hotter than the center

elements.Youcanimprove heatdistributionby loadingless ware

ina coolsectionof the kilnandmorewareina hot section.Slowing the firing also helps.

The best way to determine how to load your kiln foreven heating is to place witness cones on every shelf. You

willquicklyknowwhich sectionfires hotter andthereforeshould be loaded heavier. The heavier a section of firingchamber is loaded with ware, the cooler it will fire.


Have at least one element groove be-tween the top shelf and the top of the

kiln.

Keep ware and shelves at least 1 awayfrom the thermocouple.

Lay a ruler across the top of the kiln tomake sure the ware is not too high.

Minimum spacing between shelves is 2. You can stack posts to achieve thatheight.


24/48

Q How doyou loadthe kilnif you are firingit halfempty such as when you are firing several piecesfor a show that has a tight deadline?

ADonot leave the top halfofthe kilnempty.Dis-tribute the ware evenly throughout a lightlyloaded kiln. But if you are firinga tall piece or forsome other reason you cannot distribute theloadevenly, then fire the kiln slowly.

Q Is it okay to place ware directly onto the brickbottom?

A Yes. Since the massive firebrick bottom ab-sorbs so much heat, you should place only lightpieces on the bottom, or pieces that can be firedto a slightly lower temperature. Do not placeglazed ware on the brick bottom; running glaze

willdamage thefirebricks.Instead,place 1" postson the firebrick bottom and a shelf on top of theposts. Thebottomshelf will protect the firebrickbottom from glaze.

Note: You can also supportthe bottom shelf with smallbroken pieces of shelves.They will help to distributethe weight of the kiln loadover a larger area of the kilnbottom than would 3 or 4separate posts.

How to PositionPostsStack posts so they

aredirectly in line with

each othervertically. Ifposts are stacked ver-tically offset from eachother, shelves will beless stable and morepro ne to warp a tstoneware and porce-lain temperatures. Acantilevered shelf can break from stress. The weight on

verticallyalignedpostswillalso helptohold upashelf thatcracks.

Use 3 posts for a kiln load of fullshelves. Three posts aremorestablethan 4 posts, because with 3 pointsof support, the shelves will not rock.Use6postsforasetofhalfshelves.

When possible, position posts to-ward the kiln walls and away fromthe center of the kiln. This placesmost of the weight of the kiln loadclosetothekiln standand away fromthe kiln center, which has less sup-port.

Bead RodsFire small low-fire or

stoneware glazed beads onbead rods that are sus-pended between two posts.Keep the beads separatedon the rod. If they touch, the glaze will make them stick

together. Keep the glaze away from the bead holes.You can also center a bead rod (also called a stilt rod)overa horizontal post sothatthe rod extends pasttheposton each side. Then load an equal number of beads oneach end of the rod. This is an efficient way to fire manybeadssinceone shortpost canholdseveral rods.Becare-ful not to jar the kiln, or the rods could fall.

Firing Large WareAcross Half Shelves

Large ware such as platterssometimes extendover twohalf

shelves. If the shelves are un-even, the platter may warp dur-ing firing. To solve this prob-lem, pour a small amount ofalumina hydrate onto eachshelf. The powder will form aneven surface for the ware. Youcould also place small clayballs or pencil-sized strandsofclay under the ware. Another alternative is to place the

ware on a small shelf that spans the two half shelves.

Tile Holders

Tile holders are a special type of kiln furniture. Theymake efficient use of kiln space and allow air to circulatearound tiles for even heating, thereby reducing tile

warpageand cracking. Tileholderscan be stackedinsidethe kiln.

Some tile holders can hold tiles horizontally or verti-cally. Position the tiles horizontally when using glazesthat tend to run down a vertical plate or tile during firing.On the other hand, positioning the tiles vertically in theholderslessens thechanceofdust fallingonto theglaze.


You can support the bottomshelfwith smallshelfpieces.

Posts should be vertically aligned asshown in the left diagram.

Use 3 posts per shelf.

You can fir e large piecesacross half shelves.


25/48

FIRING THE KILNCheck the kiln from time to time during operation.

Observe the sounds that it makes, and write down thelength of firing time. Once you are familiar with the nor-mal operation ofyourkiln, you willoften knowjustbyob-servation if something goes wrong. This can alert you to

interrupt the firing before the ware is damaged.

The Stages of FiringCeramists like to fire their kilns fast to save time and

energy. Fast firing, however, can cause many mistakes.Fire greenware slowly especially during the early

stages. A fast greenware firing does not save time if itcauses glaze crazing, pinholes, orcratering. You canusu-ally fire glazed ware faster than greenware, but slow thefiringneartheendsothatglazedefectshavetimetoheal.

The thicker theware and themore densely packedthekiln, the slower the kiln must fire to insure that the heat

reaches all of the ware. Pieces thathave thin and thick ar-eas must also be fired slowly to allow the thick areas tocatch up in temperature with the thin areas.

Stage One: Water SmokingUp to 800 -900F (426 - 482C)

All clays contain water. The first stage of firing burnsoff the water in ceramic greenware. As the water heats, itexpandsand ispushedoutoftheclay.This iscalledwatersmoking.

Fast firing during this stage can lead to disaster. If thekiln heats past the boiling point of water212F(100C)the water in the clay will expand too quickly.

When the ware breaks during firing, it is usually at thisfirst critical stage. Water boiling inside the clay can ex-plode,damaging not only thewarebutalsothe walls ofthekiln. When the ware sounds like popcorn inside the kiln,

you know you have fired too fast.Maintaintemperature at200F (93C) or lowerduring

water smoking, and ventthe kilnso thatthewater canes-cape. If you dont have a pyrometer or digital controller,leave the bottom switch on low and the other switchesturned off.

Stage Two: Dehydration and QuartzInversion900 - 1100F (482C - 593C)

After the initial water smoking stage, the clay contin-

ues to lose water at a molecular level until about 1100F(593C). At that point, the clay changes chemically intofired ware. At around 1060F (571C), the clay goesthrough quart inversion, which is the point at which thesilicain theclayexpands. Through 900 - 1100F (482C-593C), themolecular water must exit theclay slowly,es-pecially if the clay pieces are large.

Stage Three: Oxidation500 - 2000F(260C - 1093C)

Impurities burn out oftheclayfromthe verybeginningof the firing, but especially during the Oxidation stage.The kiln atmosphere must have oxygen to burn the im-purities. The ware must be heated slowly to give impuri-ties, such as carbon, enough time to become gases andcombine with oxygen. The thicker the ware and the

heavier the load, the slower the ware must be fired.As the clay reaches higher temperatures, the compo-

nentsof theclay fuse together, sealingtheclaysurface.Atthis point, remaining carbon and other impurities be-come trapped ins

im104 paragon ceramic kiln inst

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