Tablet Baking

Tablets are baked for two related purposes: to preserve them and to clean them to improve their readability. Once fired to brick hardness tablets may also be more vigorously brushed to remove any remaining debris from their surfaces.

A Fisher Scientific Isotemp® Programmable Muffle Furnace (650 Series) is used for baking the tablets. Up to 3 stackable ceramic shelves will fit within the furnace. Depending on the size of the tablets, up to 40 may be fired at one time.

First the tablets are set to rise from room temperature (ca. 26ºC) to 150ºC at 0.4º/minute. It takes a bit over 5 hours to reach this temperature. The 150º is held for another 43 hours to allow all moisture within the tablets to evaporate and reduce chances of cracking or explosion due to steam build up within the tablets. Next the tablets are raised to 375º at 1.6º/minute over 2 hours and 20 minutes. A final increase takes the tablets to 675ºC at 1.4º/minute over 3 hours and 34 minutes. After this the furnace shuts down. The interior is cool enough to open within a couple days.