Annealing Schedule for Casting Crystal

Gaffer® Casting Crystal Annealing Schedules. Semi-Open and Open Forms *

Thickness


(inches)
(mm)
Anneal
Soak
Time

@ 806oF
@ 430oC
Initial
Cooling
Rate

oF/Hr
oC/Hr
Initial
Cooling
Range

oF
oC
Second
Cooling
Rate

oF/Hr
oC/Hr
Second
Cooling
Range

oF
oC
Final 
Cooling
Rate**

oF/Hr
oC/Hr
Final
Cooling
Range

oF
oC
Total 
Elapsed
Time
.5 in 
12 mm
2 hr 120
67
806 - 680
430 - 360
240
133
680 - 590
360 - 310
720
402
590 - 70
310 - 21
4hrs 10mins
.75 in
19 mm
3 hr 52
29
806 - 680
430 - 360
104
58
680 - 590
360 - 310
312
174
590 - 70
310 - 21
8hrs
1.0 in
25 mm
4 hr 29
16
806 - 680
430 - 360
58
32
680 - 590
360 - 310
174
96
590 - 70
310 - 21
13hrs
1.5 in
38 mm
6 hr 13
7.2
806 - 680
430 - 360
26
14.4
680 - 590
360 - 310
78.0
43.0
590 - 70
310 - 21
26hrs
2.0 in
50 mm
8 hr 7.8
4.3
806 - 680
430 - 360
15.6
8.6
680 - 590
360 - 310
46.8
25.8
590 - 70
310 - 21
41hrs 30mins
2.5 in
60 mm
10 hr 5.2
2.9
806 - 644
430 - 340
10.4
5.8
644 - 554
340 - 290
31.2
17.4
554 - 70
290 - 21
2 days 17hrs
3.0 in
75 mm
12 hr 3.3
1.8
806 - 644
430 - 340
6.6
3.6
644 - 554
340 - 290
19.8
10.8
554 - 70
290 - 21
4 days 5hrs
3.5 in
88 mm
14 hr 2.5
1.4
806 - 644
430 - 340
5.0
2.8
644 - 554
340 - 290
15.0
8.4
554 - 70
290 - 21
5 days 12hrs
4.0 in
100 mm
16 hr 1.8
1.0
806 - 644
430 - 340
3.6
2.0
644 - 554
340 - 290
10.8
6.0
554 - 70
290 - 21
7 days 8hrs
4.5 in
113 mm
18 hr 1.6
0.9
806 - 644
430 - 340
3.2
1.8
644 - 554
340 - 290
9.6
5.4
554 - 70
290 - 21
8 days 5hrs
5.0 in
125 mm
20 hr 1.3
0.7
806 - 644
430 - 340
2.6
1.4
644 - 554
340 - 290
7.8
4.2
554 - 70
290 - 21
10 days 9hrs
5.5 in
138 mm
22 hr 1.1
0.6
830 - 644
430 - 340
2.2
1.2
644 - 554
340 - 290
6.6
3.6
554 - 70
290 - 21
11 days 20hrs
6.0 in
150 mm
24 hr 0.9
0.5
806 - 608
430 - 320
1.8
1.0
608 - 518
320 - 270
5.4
3.0
518 - 70
270 - 21
16 days
6.5 in
165 mm
26 hr 0.7
0.4
806 - 608
430 - 320
1.4
0.8
608 - 518
320 - 270
4.2
2.4
518 - 70
270 - 21
19 days 20hrs
7.0 in
175 mm
28 hr 0.6
0.33
806 - 608
430 - 320
1.2
0.66
608 - 518
320 - 270
3.6
2.0
518 - 70
270 - 21
23 days 19hrs
7.5 in
190 mm
30 hr 0.5
0.3
806 - 608
430 - 320
1.0
0.6
608 - 518
320 - 290
3.0
1.8
518 - 70
270 - 21
26 days 6hrs
8.0 in
200 mm
32 hr 0.47
0.26
806 - 608
430 - 320
0.94
0.52
608 - 518
320 - 270
2.8
1.56
518 - 70
270 - 21
30 days 4hrs
8.5 in
215 mm
34 hr 0.41
0.23
806 - 608
430 - 320
0.8
0.46
608 - 518
320 - 270
2.4
1.4
518 - 70
270 - 21
33 days 21hrs
9.0 in
225 mm
36 hr 0.35
0.2
806 - 608
430 - 320
0.7
0.4
608 - 518
320 - 270
2.1
1.2
518 - 70
270 - 21
38 days 22hrs
9.5 in
242 mm
38 hr 0.32
0.18
806 - 608
430 - 320
0.64
0.36
608 - 518
320 - 270
1.9
1.1
518 - 70
270 - 21
42 days 6hrs
10.0 in
254 mm
40 hr 0.29
0.16
806 - 608
430 - 320
0.58
0.32
608 - 518
320 - 270
1.74
0.96
518 - 70
270 - 21
47 days 15hrs

*  Based on: Schedules for commercial annealing of ordinary ware. Corning Glassworks. Corning N.Y. 1950. For forms that are able
    to cool reasonably equally on all sides.
** Obviously cooling rates of thinner pieces are faster than ordinary kilns would lose heat. In those cases the kiln can be allowed to 
    cool at its normal rate. 
Revised schedules August 2010.

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