16 | BASIC FIRING STEPS |
B E G I N N E R
6 - MODIFYING GLASSFIRE PROGRAMS
As mentioned earlier, after visual inspection of your glass you may decide you want to modify your process tempera- ture values to create more or less heatwork in your next firing. In GlassFire Mode you can only change the Process values. The Process Values include the peak temperature and hold time at peak temperature in the program. In order to make these changes you must first toggle the Modify Glass Fire Mode Feature to the on position. For instructions on how to toggle Modify Glass Fire Mode to the on position consult the Options Mode Instructions on pg. 21 of the manual.
You can also modify a GlassFire program while the kiln is firing using the Edit Mode feature. This is covered in the Advanced section of the manual under Edit Mode Features.
WHEN TO MODIFY A PROGRAM
A program should be modified when it consistently results in either too much or too little heatwork.
A Full Fuse program should result with the glass completely fused together to a 0.25” (6.4 mm) thickness. The edges should be rounded yet the shape should not be distorted.
A successful Tack Fuse can have different looks depending on the effect desired. The least aggressive tack fuse, com- monly referred to as a “Fuse to Stick”, will bond the 2 pieces of glass together without rounding the edges. More aggressive Tack Fuses will range from slightly rounded edges to almost completely fused. These are commonly referred to as “Texture Fuses”. Factory programs are set to result in a slightly more aggressive “Fuse to Stick”.
Slumping programs tend to require the most adjusting due to the fact that every slump mold is different and the degree of slump desired can change.
HOW MUCH TO MODIFY PROGRAMS
As you gain experience you will get a feel for how much to adjust programs. It is best to start in small increments, 5 °F or 5 minutes. If you are using Add Time or Add Temp to adjust the programs you can always add more during the same
program.
TIME OR TEMPERATURE
To a certain extent both can have the same effect on the finished piece since they both add heatwork. (See General Fir- ing Guidelines - Heatwork). However, they both have different benefits and draw backs.
Increasing Hold Time allows the piece to “soak” in the heat uniformly. This is good for thicker pieces that may have differences in temperature between the outside and the center of the piece. A drawback to long holds is they can contribute to devitrification. (See General Firing Guidelines). When holds exceed 20 minutes or devitrification becomes a problem you should consider increasing the temperature.
CHANGING THE PROCESS TEMPERATURE
After you have entered the Process (Slump, Fuse, or Tac) in a program and have pressed 
the kiln will flash the cur- rent Process Temperature alternately with °F ( °C).
Press 
or 
once. The controller will quit flashing and only show the Process Temperature.
Single presses (pressing and letting go) will now adjust the temperature up 
or down 
in 1 °F (1 °C) increments. Holding these keys down will change the temperature at an increasingly faster rate.
After the desired temperature has been reached Press 
to lock in the temperature and continue programming.
The maximum temperature that can be entered is 1650 °F (899 °C).
