Gaffer® Casting Crystal Annealing Schedules.
Semi-Open
and Open Forms *
Thickness (inches)
(mm) |
Anneal Soak at
824oF
at
440oC |
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 |
1.0 hr |
120
67 |
824 - 694
440 - 368 |
240
133 |
694-604
368 - 318 |
1200
670 |
604 - 75
318 - 24 |
2hrs 53mins |
.75 in
19 mm |
1.5 hr |
52
29 |
824 - 679
440 - 360 |
104
58 |
679 - 589
360 - 310 |
520
290 |
589-75
310 - 24 |
6hrs 6mins |
1.0 in
25 mm |
2.0 hr |
29
16 |
824 - 664
440 - 353 |
58
32 |
664 - 574
353 - 303 |
290
160 |
574 - 75
303 - 24 |
10hrs 44mins |
1.5 in
38 mm |
3.0 hr |
13
7.2 |
824 - 626
440 - 330 |
26
14.4 |
626 - 536
330 - 280 |
130
72 |
536 - 75
280 - 24 |
25hrs 30mins |
2.0 in
50 mm |
4.0 hr |
7.8
4.3 |
824 - 594
440 - 312 |
15.6
8.6 |
594 - 504
312 - 262 |
78
43 |
504 - 75
262 - 24 |
45hrs |
2.5 in
60 mm |
5.0 hr |
5.2
2.9 |
824 - 566
440 - 296 |
10.4
5.8 |
566 - 476
296 - 246 |
52
29 |
476 - 75
246 - 24 |
2 days 23hrs |
3.0 in
75 mm |
6.0 hr |
3.3
1.8 |
824 - 524
440 - 273 |
6.6
3.6 |
524 - 434
273 - 223 |
33
18 |
434 - 75
223 - 24 |
5 days 4hrs |
3.5 in
88 mm |
7.0 hr |
2.5
1.4 |
824 - 486
440 - 253 |
5.0
2.8 |
486 - 396
253 - 203 |
25
14 |
396 - 75
203 - 24 |
7 days |
4.0 in
100 mm |
8.0 hr |
1.8
1.0 |
824 - 454
440 - 234 |
3.6
2.0 |
454 - 364
234 - 184 |
18
10 |
364 - 75
184 - 24 |
10 days 15hrs |
4.5 in
113 mm |
9.0 hr |
1.6
0.9 |
824 - 417
440 - 214 |
3.2
1.8 |
417 - 327
214 - 164 |
16
9 |
327 - 75
164 - 24 |
12 days 14hrs |
5.0 in
125 mm |
10.0 hr |
1.3
0.7 |
824 - 383
440 - 195 |
2.6
1.4 |
383 - 293
195 - 145 |
13
7 |
293 - 75
145 - 24 |
17 days 4hrs |
5.5 in
138 mm |
11.0 hr |
1.1
0.6 |
824 - 347
440 - 175 |
2.2
1.2 |
347 - 257
175 - 125 |
11
6 |
257 - 75
125 - 24 |
21 days 6hrs |
6.0 in
150 mm |
12.0 hr |
0.9
0.5 |
824 - 312
440 - 156 |
1.8
1.0 |
312 - 222
156 - 106 |
9
5 |
222 - 75
106 - 24 |
27 days |
8.0 in
200 mm |
16.0 hr |
0.47
0.26 |
824 - 172
440 - 78 |
0.94
0.52 |
172 - 82
78 - 24 |
-
- |
-
- |
62 days |
* 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.
Copyright: Gaffer® Coloured Glass Ltd. 1998.
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