Manual Glass Kiln
China paints will
crack or peel if ap
-
plied heavily. Apply
several light coats in
-
stead, firing between
each,untilyougetthe
shade you want. Not
all china paint colors
reach maximum
colorsaturationatthe
same temperature
even when fired on
thesameware.Soyou
mustknowwhichcol
-
ors you should fire
first at higher tem
-
peratures to prevent burning out the original colors in later
firings. For example, reds mature at a lower temperature
than other colors and are fired after the other colors have
beenfired.Redsandyellowsshouldnotbefiredsidebyside.
Colorsalsomatureatalowertemperatureonceramicpieces
thanonporcelainorhardchina.Checktheoverglazemanu
-
facturer’s literature for information on which cone to use
with each color and type of ware.
Vent the door during the first hour of firing. If your kiln
has a vent hole, leave it open during the entire firing. Allow
kiln to cool to room temperature before opening the door.
Lost Wax Burnout
Caution: Only kilns with vent holes are designed
for lost wax burnout. However, you can use a kiln
without the vent hole provided that you open the
door ½” during venting.
Caution: Always use a wax tray.
Caution: If your kiln’s heating element is embed
-
ded in the floor of the firing chamber, place the
metal wax tray on 3 or4-½”posts inside the kiln.
This prevents the element from possibly shorting
out against the tray.
Note: Theseinstructionsapplytoinjectionwaxthat
melts at 200°F, not pattern waxes and plastics that
meltathigher temperatures.Ifsmokeappearsdur
-
ing waxelimination, turnoff the kiln. Smoking wax
means the kiln fired hotter than 300°/148°C.
Overview
Lostwaxcastingistheprocessofcarvingashapeinwax,
andthencasting that shapein metal. Afterthe waxhas been
carved,amoldismadeofthewaxshape.Themoldisanega-
tiveimageofthewax.Thewaxislatermeltedoutofthemold
through hollow channels called sprues.
Lost wax burnout is the process of preparing a casting
mold for the melted metal that will be poured into it. The
steps in lost wax burnout:
1 Melt the wax from the mold.
2 Remove wax from the kiln before raising the tem-
perature higher than 300°F/148°C.
3 Harden the mold at high temperature.
4 Maintain the mold at the casting temperature rec
-
ommendedforthe typeofmetalthatwillbepoured
into the mold.
Caution: Prevent wax or carbon from contacting
the kiln’s walls and elements. Carbon build-up in
-
sideakilnruinstheinterior.Carbonconductselec
-
tricityandcauseselementstoshortcircuit.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.