For work 1 1/2" or more and over 24" (61 cm) in any direction Uroboros recommends using kilns with top, side and bottom heating.
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Firing Schedules (ramps are for 6" or larger open face firings on shelves) | ||||||||||||
| Heating | Annealing Cooling | ||||||||||||
| Step 1 | Step 2 | Step 3 | Step 4 | Step 5 | Step 6 | ||||||||
| Target temps >> |
1250° F 677° C |
To Desired Peak Temp (see Peak Temp Table) |
960° F 516° C |
775° F 413° C |
500° F 278° C |
75° F 42° C |
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| Maximum Thickness |
Ramp Rate (per hour) |
Hold (minutes) |
Ramp Rate (per hour) |
Hold (minutes) |
Ramp Rate (per hour) |
Hold (minutes) |
Ramp Rate (per hour) |
Hold (minutes) |
Ramp Rate (per hour) |
Hold (minutes) |
Ramp Rate (per hour) |
Hold (minutes) |
Minimum Total Time (hours) |
| 1.5" | 150°F | 150 | 150°F | Per Peak Temp Table |
AFAP* | 360 | 12°F | 0 | 24°F | 0 | 75°F | 0 | 56 (2.3 days) |
| 38 mm | 83° C | (2.5 hrs) | 83° C | (6 hrs) | 6.7°C | 13° C | 42° C | ||||||
| 2" | 125°F | 180 | 125°F | Per Peak Temp Table |
AFAP | 480 | 7° F | 0 | 14° F | 0 | 42° F | 0 | 84 (3.5 days) |
| 51 mm | 69° C | (3 hrs) | 69° C | (8 hrs) | 3.9°C | 7.8°C | 23° C | ||||||
| 3" | 100°F | 225 | 100°F | Per Peak Temp Table |
AFAP | 720 | 3° F | 0 | 6° F | 0 | 18° F | 0 | 166 (6.9 days) |
| 76 mm | 56° C | (3.8 hrs) | 56° C | (12 hrs) | 1.7°C | 3.3°C | 10° C | ||||||
| 4" | 75° F | 270 | 75° F | Per Peak Temp Table |
AFAP | 960 | 1.5° F | 300 | 3° F | 0 | 9° F | 0 | 311 (13 days) |
| 102 mm | 42° C | (4.5 hrs) | 42° C | (16 hrs) | 0.8°C | ( 5hrs) | 1.7°C | 5° C | |||||
| 5 " | 68° F | 305 | 68° F | Per Peak Temp Table |
AFAP | 1200 | 1.2° F | 375 | 2.4° F | 60 | 7.2° F | 0 | 386 (16.1days) |
| 127 mm | 38° C | (5.1hrs) | 38° C | (20 hrs) | 0.7°C | (6.3 hrs) | 1.3°C | ( 1 hr) | 4° C | ||||
| 6" | 60° F | 340 | 60° F | Per Peak Temp Table |
AFAP | 1440 | 0.8° F | 450 | 1.5° F | 150 | 4.5° F | 0 | 577 (24 days) |
| 152 mm | 33° C | (5.7 hrs) | 33° C | (24 hrs) | 0.4° C | (7.5 hrs) | 0.8° C | (2.5 hrs) | 2.5° C | ||||
| 7" | 55° F | 375 | 55° F | Per Peak Temp Table |
AFAP | 1680 | 0.6° F | 525 | 1.2° F | 225 | 3.4° F | 0 | 740 (30.9days) |
| 178 mm | 31° C | (6.3 hrs) | 31° C | (28 hrs) | 0.3° C | (8.8 hrs) | 0.7° C | (3.8 hrs) | 1.9° C | ||||
| 8" | 50° F | 405 | 50° F | Per Peak Temp Table |
AFAP | 1920 | 0.4° F | 600 | 0.8° C | 300 | 2.4° F | 0 | 1071 (44.6days) |
| 203 mm | 28° C | (6.8 hrs) | 28° C | (32 hrs) | 0.2° C | (10 hrs) | 0.4° C | (5 hrs) | 1.3° C | ||||
| **AFAP means As Fast as Possible |
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| Basic Definition of firing steps | |
| Step 1 | Heat glass, small prefired components & shelf/mold materials above the softening point. Hold to distribute the heat evenly, and to allow air to escape (bubble management). |
| Step 2 | Fire to desired peak temp Hold to desired finish |
| Step 3 | Drop to upper annealing point Hold to distribute the heat evenly. |
| Step 4 | Annealing ramp: cool to below the strain point Hold |
| Step 5 | 1st Cooling ramp Hold |
| Step 6 | 2nd Cooling ramp Open kiln when kiln interior is at room temperature. |
| Peak Temperature Table - Open Face Molds | |||
| This guide is intended as a starting point. Variations of 25° F (13.9° C) or more are expected for specific needs & circumstances, such as kiln type, rate of ramp-up, soak length, thickness of work or mold, etc. All other factors being equal, System 96 glass will require a peak temperature about 25° F (13.9° C) below Fusion FX 90 COE (Bullseye compatible) glass. | |||
| Activity | Temp F | Temp C | Hold Time |
'Sugar' firing (sintering) |
1300° 1325° 1350°-1375° 1420°-1450° 1450°-1475° 1475°-1500° |
704° 718° 732°-745° 771°-788° 788°-802° 802°-816° |
1-20 mins 1-30 mins 10-45 mins 15-90 mins 15-90 mins 90-300 mins |
Revision 03/09