Programming instructions

8 Single Segment/Ramp-Hold
Lost Wax
Burnout
CAUTION: Only kilns with vent holes are designed
for lost wax burnout. However, you can use a kiln with
-
out the vent hole provided that you open the door ½”
during venting.
CAUTION: Always use a wax 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 during
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 neg
-
ative 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:
Melt the wax from the mold.
Remove wax from the kiln before raising the tem-
perature higher than 300°F/148°C.
Harden the mold at high temperature.
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 inside a
kiln ruins the interior. Carbon conducts electricity and
causes elements to short circuit. Damage to elements
from contact with foreign materials is not covered by
warranty.
A Sample Program
See instructions on page 7 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
Segment 1 heats the wax to 300°F/148°C and holds it for
one hour, allowing it to drip from the mold.
Segment 2 hardens the mold.
Segment 3 lowers temperature to 800°F/426°C, the typi
-
cal casting temperature for silver. (Most types of gold cast
at 900°F/482°C.)
Note: Casting temperature depends on the size of the
mold. The temperatures above are only a guide. See
your jewelry supply dealer for temperature
recommendations.
Burnout Instructions
Place a metal tray inside the kiln on three ½” posts.
Place the mold on a wire mesh screen on top of the
tray. The mold’s sprue hole should be down. The
tray will catch melting wax as it drips from the
sprue hole.
Keep the kiln’s vent hole(s), if any, open during
wax elimination. If the kiln has no vent hole, leave
the door open ½”. This allows fumes to escape the
kiln. Heat the kiln to 300°F/148°C and hold it at
that temperature for at least one hour.
Note: Do NOT heat the wax above 300°F/148°C. Hold
at 300°F/148°C for at least one hour. During this hour,
the wax will melt from the mold and drip into the tray. If
the kiln gets hotter than 300°F/148°C, the wax may
smoke and deposit carbon inside your kiln, causing ex-
pensive damage.
After one hour at 300°F/148°C, open the kiln. Re-
move the mold and wax tray. Pour the wax from the
tray and leave the tray out of the kiln until your
next wax elimination. (Do not leave the tray in the
kiln!)
Heat the mold to the temperature recommended
by your jewelers’ supply house where you pur
-
chased the mold material. This is usually around
1350°F/732°C.
Lower the temperature to the casting temperature
of the metal. Hold at that temperature until you
are ready to begin casting. Remove the mold with
tongs. Wear protective gloves and safety glasses.
Saving a Carbon-Damaged Kiln
If you follow the above directions, your kiln should be
safe from wax damage. In some cases, a small amount of
carbon may form on the walls over a period of time. This is
due to the burning of wax residue that was left in the mold.
For this reason we recommend that you periodically fire the
kiln to 1500°F/815°C as follows:
Open the vent cover(s) or leave the door ajar ½”.
Fire the kiln empty to 1500°F/815°C at a rate of
300°F/166°C with a one hour hold (01.00).