|Monthly Tech-Tip |
In industry fast drying and firing are standard, but potters still dry for days and firing cycles are often 24 hours. But it is surprising how much even very plastic clay can be pushed. This porcelain slurry dewatered to plastic in 30 minutes. I threw the mugs and attached handles after 15 minutes fan-drying, then put them into a 240F test kiln immediately (with exhaust fan going). This created a high humidity hot zone that dried them quickly and evenly (trimmable in 15 minutes, ready to green-glaze inside in 30, glaze outside 15 more). Then I fired them to 1-hour-soak at 240F and go full speed to cone 6, soak 10 minutes and shut off. I ice-watered them when they hit 300F on cool-down (IWCT test). I did get a bubble on the outside of one and a weird surface crack traveling about 5 mm below the rim on the other, so a few minutes extra glaze drying time was needed before firing.
Drying Ceramics Without Cracks
Anything ceramic ware can be dried if it is done slowly and evenly enough. To dry faster optimize the body recipe, ware cross section, drying process and develop a good test to rate drying performance.