[Clayart] humidity

[Sharon Cary]

I discovered years ago that my small pieces, covered with pieces of cotton sheets, would dry nicely and relatively faster than under plastic. If they need additional work, a sheet of plastic Over the cloth would keep them leather hard until time to trim. The salt shakers I make are by nature thicker at the bottom and would develop stress cracks if left uncovered, but just keeping the drafts off with cloth solved that and let them dry. Small slab plates don’t warp when covered this way as well. 

S.Cary -
Make something beautiful every day. 
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> On Mar 7, 2023, at 8:15 AM, Snail Scott <claywork at flying-snail.com> wrote:
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>> On Mar 7, 2023, at 6:48 AM, mel jacobson <melpots at mail.com> wrote:
>> In many ways sheet plastic wrapped around sculptures has the opposite affect.
>> The water migrates to the plastic like a rain forest and drips back onto the
>> piece….I met an amazing sculptor...She wrapped her sculptures in linen...
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> Yes. Plastic is, in my mind, the biggest game-changer in the history of ceramics since the kiln. Gas, electricity, cones, frits…all that is just modifications and upgrades.  Plastic makes keeping clay wet incredibly easy. When Rodin travelled around France, schmoozing the collectors, he left poor Camille Claudel back in the studio to wet down the rags every day,  keeping the work-in-progress workable until he returned. Imagine what she could have accomplished with a box of trash bags and some free time!
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> However, plastic is not good for keeping the moisture even, and does not allow clay to dry evenly, either. When sealed up and kept tight to the clay, thick plastic holds moisture in for quite a while. When loosely draped, though, condensation gathers at the top during overnight chill. It drips down onto the top, and runs in rivulets to puddle in the bottom…the bigger the work, the bigger the issue. When people want to start drying the work, they tend to drape the plastic loosely, with gaps which cause uneven evaporation. 
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> I cover work in progress with thick cotton sweatshirt fabric or cotton towels under the plastic.  When I want the clay to be softer, I spray the cloth with water, dampening it and creating a humidifier inside the plastic environment. The cloth wicks the moisture evenly, and it catches and redistributes condensation. (For serious rehydration, direct contact with damp cloth is the way to go, though…water is held against the clay and does not run off into a puddle. like sprayed water does.)  When I want the clay to stiffen, I swap the cloth once or twice daily for dry cloth, removing just the moisture that had absorbed from the atmosphere inside the plastic. The cloth does not need contact with the clay to do any of this…it affects the humidity under the plastic, not the clay directly.  The more cloth, the greater the effect, both for dampening and dehydrating. When the entire piece has reached the stiff leather-hard phase, beginning to turn pale, I remove the plastic and wrap it in just cloth. It permits evaporation, but slower and more evenly than open air exposure, with no drafts. I have refined this over many years, and it works. Cloth inside plastic is a portable damp box; and folds flat when not in use! Stacking bins are great for small pots, but not for larger work. 
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> It frustrates me to see people covering work well in plastic and wondering why it won’t dry, or draping plastic with big gaps at the side. creating dry spots and irregular shrinkage. Perforated plastic is better, but it can’t move the moisture like cloth can. Drying ’slow’ is not the goal; drying evenly is.
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> -Snail Scott
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