Friday, April 17, 2009
April is the cruelest month...
This time of year when the Midwestern air is constantly fluctuating between dry and damp, warm and cold producing work in the studio always presents a challenge. Tiles that only a month ago would dry nice and flat now curl and crack in only a few hours or they can sit for days without losing any moisture.
Back when we were making our ware out of earthenware clay drying wasn't so much of a problem, occasionally a plate would get that ugly hump rising up in the middle but for the most part it was make it and forget it. Even when we made the switch to a tighter cone 6 porcelaneous stoneware clay the pieces would pretty much dry well on their own. It wasn't until we started working with the really tight (under a percent absorbtion) porcelain clays that we had to start paying attention to our drying processes. What was once a nice round bowl would suddenly come out of the kiln transformed into a disheartening, unwelcome ovoid shape.
Finding a working solution to this problem was no easy undertaking and it took a painful amount of time. We would make a batch of work, analyze the drying process, and then wait until after 2 kiln firings to study the results.
To complicate matters, researching the problem revealed an amazing amount of misinformation that lead to many dead ends - the tried and true bag it and let it dry slowly for weeks and weeks just doesn't work in a production setting. Luckily there are easy to understand methods that have been developed by the ceramic industry. I was reminded of this by a recent article published over at the Ceramics Industry Website. The great thing about an article like this is that it provides enough information to help you find your own solution on a much smaller (and monetarily attainable) scale. Here are some links to other similar articles that helped us gain insight into the mechanisms of drying clay.