Covering Everything, Even for a Ten-Minute Detour
Okay, so this lesson is short and I mean that as a compliment to myself, because I usually run long. This one's simple. Cover your work. All of it. Every time. Even when you're only stepping away for a minute.
I know how that sounds. I know it sounds like the kind of thing an instructor says to cover herself, the pottery version of "please drive safely." It's not that. I'm telling you this because I lost an entire batch of bowls to it once, and I'd rather you not repeat my mistake than feel smart for skipping a step.
Here's what happened. I had four slabs cut and starting to firm up on the table, and I went to answer a work email. One email. Maybe ten minutes. I came back and the edges of every slab had gone stiff and pale, like they'd aged a day in the time I was gone. I tried to work with them anyway because I was annoyed and didn't want to start over, and every single one cracked either right then or later in the kiln. Four bowls, gone, because I trusted the clay to wait for me the way a document waits for me. It doesn't. It's not a Word file. It's actively drying the second it's exposed to air, and our air here is not gentle about it.
We sit around 4,600 feet with low humidity most of the year, and that combination pulls moisture out of clay fast. Faster than people expect if they've seen tutorials filmed somewhere humid. A slab that would stay workable for half an hour in a wetter climate can skin over here in ten minutes. That's not a exaggeration for effect. That's just what dry air at elevation does, and it doesn't care that you were "just checking something real quick."
What covering actually looks like
This isn't complicated, which is sort of the point.
- Plastic sheeting or a garbage bag, draped loosely over the piece. Loosely matters. You're not trying to seal it airtight against the table, you're trying to slow the air from getting at it.
- A damp (not wet) paper towel underneath the plastic if you're stepping away for longer than a few minutes, or if the piece is thin. Damp meaning you wrung it out, not meaning it's dripping. Dripping towels make soggy, sad edges.
- Shower caps. I buy the giant multi-pack at Costco, not for anyone's shower, for this. People think I'm joking when I recommend this and then they try it and they're converts. They stretch over bowls, cups, anything round, and they seal well enough to actually hold moisture in.
- A cutting board or plate on top of loose plastic if you're worried about it blowing around, though honestly that's rarely the issue at a kitchen table.
The habit I want you to build is this: the second your hands leave the piece, something goes over it. Not "when you remember." Not "when it's convenient." The second your hands leave it.
Why this matters more than it seems like it should
You already know from the moisture lesson that leather-hard clay behaves differently than wet clay, and that joining two pieces at different moisture levels is asking for a crack. Covering is how you control that. If one slab dries a little and another stays wet because you covered it and forgot the other one, you've created the exact mismatched-moisture problem that ruins joins. It's not really a separate rule from score-and-slip. It's upstream of it. You can score and slip perfectly and still crack a piece if the two sides you're joining have quietly drifted apart in dryness while you weren't looking.
And I will say the thing again, because it's the one place I don't budge: score and slip every join, no matter what. No exceptions, no "it's a small piece so it'll be fine." I've watched too many pots crack in the kiln from a corner someone decided didn't need it. Covering your work and scoring your joins aren't separate good habits. They're the same habit, really, just applied at different moments. Both of them are about respecting that this clay is moving the whole time you're not paying attention to it, whether you're in the room or answering an email.
A practical habit to build in
Get a piece of plastic or a shower cap within arm's reach before you start working, not after you realize you need one. If you have to get up to find something to cover your slab, you've already lost thirty seconds you didn't need to lose, and thirty seconds matters more here than it feels like it should.
Before next time
Set up your workspace once with a stack of plastic sheeting or a couple of shower caps sitting right next to where you'll be working, so covering something becomes the easy choice instead of the extra step.
~erin