background image

China paints will

crack or peel if ap-

plied heavily. Apply

several light coats in-

stead, firing between

each, until you get the

shade you want. Not

all china paint colors

reach

maximum

color saturation at the

same temperature

even when fired on

the same ware. So you

must know which col-

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

been fired. Reds and yellows should not be fired side by side.

Colors also mature at a lower temperature on ceramic pieces

than on porcelain or hard china. Check the overglaze manu-

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.

Lost Wax Burnout

Caution:

Only kilns with vent holes are designed

for lost wax burnout. However, you can use a kiln

without the vent hole provided that you open the

door ½” during venting.

Caution:

Always use a wax tray.

Caution:

If your kiln’s heating element is embed-

ded in the floor of the firing chamber, place the

metal wax tray on 3 or 4 - ½” posts inside the kiln.

This prevents the element from possibly shorting

out against the tray.

Note:

These instructions apply to injection wax that

melts at 200°F, not pattern waxes and plastics that

melt at higher temperatures. If smoke appears dur-

ing wax elimination, turn off the kiln. Smoking wax

means the kiln fired hotter than 300°/148°C.

Overview

Lost wax casting is the process of carving a shape in wax ,

and then casting that shape in metal. After the wax has been

carved, a mold is made of the wax shape. The mold is a nega-

tive image of the wax. The wax is later melted out of the mold

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-

ommended for the type of metal that will be poured

into the mold.

Caution:

Prevent wax or carbon from contacting

the kiln’s walls and elements. Carbon build-up in-

side a kiln ruins the interior. Carbon conducts elec-

tricity and causes elements to short circuit. Damage

to elements from contact with foreign materials is

not covered by warranty.

A Sample Program

See your digital controller instruction manual 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

14

Open the door ½” to vent the kiln if your kiln

does not have vent holes.

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.

Summary of Contents for Glass Kiln

Page 1: ...1 Beadmaking Glassblowing Fusing and Glass Kiln Manual Sundance Glass ...

Page 2: ... 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 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 in...

Page 3: ... 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 G Unplug kiln when not in use G Do not touch hot sides G Keep unsupervised children away G Place kiln on a non combustible surface G Do not install closer than 12 from any wall or combus...

Page 4: ... special ventilation 2 Remove gasoline paint and other flammable materials from the kiln room 3 Provide a minimum of 12 inches clearance between kiln and the closest wall 4 Never allow the room temperature of your firing room to exceed 100 110 F Measure the tempera ture about 3 feet from the kiln If necessary use fans to lower room temperature 5 Keepthekilnawayfromcurtainsorothercombusti ble mater...

Page 5: ...n a smooth thin layer The smoother the glass separator the smoother the underside of the glass Alumina Hydrate Delicate silver or gold clay shapes may need extra support during firing to prevent warping Place these shapes in a thin layer of alumina hydrate inside a small ceramic bisque bowl Do not breathe alumina hydrate Stilts Stilts are points embedded in a ceramic base The points separate ename...

Page 6: ... time I Total firing time I Type of pieces I Firing results As you gain experience you will find a 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 1700 F At low temperatures turning on the heating ele ment affects firing temperature to a larger degree than at high temperatures Wh...

Page 7: ...bottom You can also slump glass over a mold such as a bowl The kiln shelf and sagging mold must be coated with glass separator to keep glass or ceramic glaze from sticking to them A coat of glass separator or kiln wash will usually last through several firings When the shelf coating begins to crack or chip apply a fresh coat When recoating a shelf re move most of the old coating with grit cloth av...

Page 8: ...lay At the time of printing the silver clay brands available were Art Clay Silver and Precious Metals Clay Silver clay looks and feels like modeling clay It is formed with simple tools such as a tooth pick small knife and razor blade Its surface is pliable and accepts impressions from objects such as leaves coins and coarse fabrics After the sil ver clay is formed it is fired in a kiln The recomme...

Page 9: ...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 you may need to check the fusing progress of the glass by opening the door and looking inside Look for just a second or two As you gain experience you will be able to program the correct temperature for the silver clay and glass combination elimi...

Page 10: ...iece may crack even several months after fus ing When different glasses have a close enough coefficient of expansion to fuse successfully they re called 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 To test glass for compatibility fuse small square sample pieces of different gla...

Page 11: ...oller for a higher tempera ture than the estimated fusing temperature Watch the glass by opening the door 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 every firing be sure you are near the kiln before the expected shut off time 3 After you sh...

Page 12: ...m the different rates of expansion and contraction in copper and enamel after the enamel has been fired Counter or backing enamel a mixture that gives a mot tled effect can be used for counter enameling Or you can use regular enamel Counter enamel is applied by the sifting method described below When firing counter enamel underfire it so that the fire scale on the front of the piece isn t too diff...

Page 13: ...tric cones are small pyramids of clay and mineral oxide that soften and bend when exposed to heat They indicate when ceramic ware has fired to maturity Pyrometric cones come in 1 1 8 and 2 lengths Use the 2 cones Cones mounted on the kiln shelf mustbeslanted8 fromver tical They will not bend ac curately if they are slanted to the wrong angle Self supporting large cones have the correct slant built...

Page 14: ... 148 C Overview Lost wax casting is the process of carving a shape in wax and then casting that shape in metal After the wax has been carved a mold is made of the wax shape The mold is a nega tive image of the wax The wax is later melted out of the mold 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...

Page 15: ...on the walls over a period of time This is due to the burning of wax residue that was left in the mold For this 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 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 Silver Clay Cracks Cracks that appear in fired silv...

Page 16: ...ture for several minutes Ceramic Overglaze Breaking in Overglaze Firing Can be caused by poorly fired bisque A slow bisque fire is always better for ware that is to be china painted The greenware should be completely dry before being placed in the kiln Purple Spots in Gold Usually due to a thin application of gold or too much thin ner If gold is applied accidentally to an area it will show pur ple...

Page 17: ...ver and look for a loose wire touching the case Temperature is Inaccurate I Make sure the ther mocouple is pushed into the firing chamber I If the thermocouple is pushed into the firing chamber and the temperature is inac curate replace the thermocouple 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 the...

Page 18: ...hamber The twisted end must extend into the fir ing chamber by Make sure the band holds the thermocouple Otherwise the thermocouple can be pushed out re 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 compo nents and other wires 9 Strip of insulation from the ends of the thermo couple w...

Page 19: ...ontrol ler faceplate to the switch box Carefully lift out face plate 3 Disconnect the wires from the back of the board You will find two plugs and two sin gle wires 4 Connect the wires to the new board Rein stall faceplate 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 th...

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