Cleaning the Rim So It Isn't Ragged
Okay. You've got a bowl shape now, walls curved from the inside, and probably a rim that looks like it's been through something. That's normal. The rim takes the most abuse of any part of the pot because it's the edge, and edges are where clay gets thin and tired and torn up from four or five pulls of your fingers dragging across it.
We're going to clean that up now, before you trim, before you do anything else. A ragged rim isn't just ugly. It's usually thinner than the rest of the wall in spots, and thin spots crack in the kiln or chip the first time you set a spoon down in it.
What a ragged rim actually looks like
Little flaps. Cracks starting at the very top edge, maybe a quarter inch down. Uneven height, higher on one side than the other. Sometimes a lip that's folded over itself from your fingers pinching too hard on the last pull.
None of that means you did the pull wrong. It means the rim is the last place your hands touched, and hands are messy tools. That's just what happens.
Cutting it level first
Before you clean the edge itself, check if it's even. Hold a needle tool or a rib horizontally against the rim while the wheel spins slow, and watch for the tool to bounce up and down. If it bounces, your rim's not level. That's fine, we fix it now instead of firing a bowl that looks drunk.
Take a needle tool, hold it steady at the height of the lowest point on the rim, and let the wheel bring the clay to the blade. It'll shave off the high spots as it spins past. Go slow. You're not sawing, you're just letting rotation do the cutting while you hold still. Lift straight up and out when you're done, don't drag it sideways or you'll catch a groove.
Compressing the edge
Once it's level, wet your fingers — really wet, I run wetter than a lot of people teach and I'm not going to change that here — and press your first two fingers down onto the rim from above while your other hand supports the wall from inside and out. Let the wheel turn slow under your fingers, one or two rotations, no more. You're compressing the clay fibers at the top edge so they don't spring apart later. A dry-handed pass on the rim tears it. A wet pass smooths it. That's the whole reason I run wet.
You'll feel the rim go from a rough edge to something rounded and a little slick. That's it. That's the fix. You don't need a tool for this part, just fingers and water.
The chamois, if you've got one
Some people use a little strip of chamois leather dragged around the rim for a final polish. It costs about three dollars at the studio supply and it's genuinely nice, but it's optional. Your wet fingers do 90 percent of the job. I mention the chamois because people ask, not because you need to buy one today.
Why I make you check thickness here, not later
This is the part where I'll tell you about the hole. Early on I trimmed a bowl down thin because I liked how light it felt in my hand, kept going past where I should've stopped, and put my trimming tool clean through the bottom. Just a hole, straight through, and me sitting there looking at it like it might fix itself.
I didn't throw the bowl away. I cut it in half instead, right down the middle, so I could actually see the wall thickness I'd been guessing at the whole time. Turned out the walls thinned out toward the bottom in a way I couldn't have told just by pinching the clay from outside. Learned more from that cross-section than from ten bowls that turned out fine.
So here at the rim, take thirty seconds and pinch the wall between thumb and finger going around the whole edge. You're feeling for consistency, not a number. If one side feels half as thick as the other, that's where it'll crack or slump first. Better to know now, while it's wet and fixable, than to find out with a hole in the bottom.
A caution, plainly
The needle tool is sharp enough to catch a fingertip if you're pushing instead of letting the wheel do the work. Keep your grip loose, keep the motion slow, and if the tool starts dragging instead of shaving, stop and check your angle before you push harder. Pushing harder is usually how people get cut.
Before next time
Clean up the rim on the bowl you've got sitting on your wheel right now, then walk away from it for the day. Tomorrow, before you trim it, run your fingers around that rim again and see if it still feels even to you. Sometimes clay moves a little overnight and you catch things a day later that you missed wet.