6 Cone-Fire / Ramp-Hold
Cone-Fire Programming
Instructions
From
, press
.
Using the
key (not the
),
skip past
and se-
lect
. Then press
.
The last pyrometric cone you fired, and its tem-
perature, will appear. Use the arrow keys to
change the cone number. Then press
.
(slow)
(medium) or
will
appear. Use the arrow keys to change speed.
Then press
.
and the hold time from the last firing will
appear. (Example: 1 hour and 10 minutes =
01.10) Use the arrow keys to change the hold
time. Then press
.
will appear. Press
.
will ap-
pear, the Run indicator light will begin blink-
ing, and the kiln will begin firing.
To stop a firing before completion, press
.
will appear, alternating with kiln
temperature.
Note:
Do not be concerned if your kiln makes a
clicking sound during firing. Kilns use relays to
power the elements. The relays click each time
their electrical contacts come together.
Note:
The kiln’s actual firing rate may be less than
the rate you programmed, depending on the kiln
model, available voltage, and density of the load
you are firing.
When the kiln fires to completion, it will beep for 30
seconds. The display will show the following:
I
Firing time
I
Present temperature
I
= fired to completion
To return to
, press
.
I
If the kiln still does not fire hot enough, then fire to the
next hotter cone number, without hold time.
I
Adjust the Thermocouple Offset. See page 13.
I
Customize the firing in Ramp-Hold.Seethe next page.
Compensating for an Over-Fired Cone
I
Fire to the next cooler cone number.
I
If firing to the next cooler cone number results in un-
der-firing, add hold time.
I
Adjust the Thermocouple Offset. See page 13.
I
Customize the firing in Ramp-Hold.Seethe next page.
Cone-Fire Hold
Cone-Fire Hold heat-soaks the ware at the cone temper-
ature at the end of the firing. Without Hold, the kiln shuts
off after it reaches the cone temperature. Hold maintains
the cone temperature for the period you specify.
Hold is not needed in every firing. Experience will help
you decide when to use Hold. Some of the reasons you
might consider using it:
I
To even out the temperature throughout the kiln.
I
To allow heat to penetrate more completely into the
clay. (Rapid firing is like cooking: the turkey will be
done on the outside but not on the inside.)
I
To help glaze absorb china paint.
I
To heal glaze defects such as bubbles.
CAUTION:
Use hold sparingly. A little hold time can
yield dramatic results. But too much can overfire your
ware and burn out colors.
One way to add hold time without over-firing is to fire to
one cone cooler than needed. Then add enough hold time
to bend the next hotter cone. Hold time needed to bend the
next cone will vary. As a rule of thumb, 45 - 60 minutes of
hold = one cone of heat work.
Example: to fire to cone 05, program Cone-Fire for 06
and add 45-60 minutes of hold time.
If your kiln has a peephole, watch the pyrometric witness
cones during firing. Press
when the correct witness
cone bends. Note how much Hold time was needed. Pro-
gram that much Hold time the next time you fire the same
type of ware.
Note:
During Hold, the display temperature will alter-
nate with time left in Hold. To figure hold time for the
next firing, subtract time left in Hold from the total hold
time entered.
When Hold is set to 99.99 hours, the Sentry Xpress will
remain at that temperature indefinitely, until
is
pressed.
