A pinch pot begins as an incredibly tiny choice of thumb location. Where exactly do you decide to set your digit? How deep do you press in? How thick do you want the bottom of the pinch pot? For a little while, everything seems fine, and then all of a sudden the walls start flaring, tipping, or the rim begins to sag. This does not signify a disastrous failure of the form. More likely than not, this just shows you something about your pressure, wall thickness, wetness, and how you are spinning the pinch pot.
Pinch pots lose their shape for all kinds of reasons, but one common culprit is unbalanced or uneven pressure. If you pinch down hard with one thumb or one side and less on the other side, the wall of your form has a thinner wall on one side and a very thick wall on the other. That side that is thinner will stretch faster when you pinch, particularly when the clay is quite wet. This means it will start to flare or droop more than the other side. It is often much better to press not as deep as you think you have to, and then rotate the form and press again. Many, many tiny little presses make a far more solid, stable wall than one big strong squeeze.
Another frequent problem area is the bottom of the pinch pot. Lots of new pinch pots have unstable bases. If you are paying too much attention to opening the hole in the middle, you might neglect paying attention to the bottom base. If your base is too thin, your pinch pot form will feel very light and weak. That light base might make you tilt your pot to the side when you pinch the walls up. And if you have a very thick base, the walls on your pinch pot might not seem to want to connect to that base. Pinch pots also tend to have uneven walls. Check your bottom pinch pot base first. Does the form sit flat on your board? Does it have a slight wobble? This is the easiest moment to correct. If you wait to check if the base sits level once the rim has already flared, you might have a much harder time.
Wetness also determines how the walls of your pinch pot act. Very wet clay can be great to pinch, but if it has gotten too wet from your fingers, a sponge, or repeated rubbing, the walls might start to stop holding height. The surface might look wet and slimy, or the pinch pot rim might easily start to droop when you pinch it. At this point, adding more water to your hands won’t help; you will just make the pinch pot even more difficult to shape and hold onto. Instead, let the pinch pot rest while the clay gets slightly firmer. You should be able to gently pinch without the wall feeling very slushy.
Let’s try making a pinch pot together! Get yourself a small lump of clay and see if you can make the slowest pinch pot you can. Open your pinch pot hole in the center and leave your bottom base strong. Now, start pinch potting around the wall and rotate your pinch pot after every pinch or two. Once you’ve circled the form once, stop and check your pinch pot walls. Run your hand around them and feel if you think they feel even. Do not smooth or rub the walls yet. First, notice where it feels thick or thin. Is the rim starting to rise in one spot or droop in the other?
Another common reason that rim drooping or flaring starts to happen is that the pinch pot rim has been overworked. Every time you try to fix or even out the rim, the clay will shift. If you run a finger around the whole circumference of the pot trying to even things out, you can stretch the clay out too wide and too thin. Try using one hand to support the outside wall while you pinch the inside wall and make small, minor adjustments. Think about pressing upwards into your form to create height, and slightly inward as you squeeze. You want to keep your pinch pot wall standing up rather than allowing it to droop and slouch down.
The goal here is a steadier pinch pot. It is not just about forcing your pinch pot walls into a more even circle. Instead, think through all of these things as you build: the base, the wall, the thickness, the rim, and the wetness. Every time your pinch pot starts to tip over or flare, pause. Do not jump ahead to smoothing the surface; think about what might be wrong first. Are the pinch pot walls thinner in one area than another? Was the pinch pot rim a little too wet? Are the walls a little wetter in one area? This might just seem like your form is falling apart at this point, but it is actually useful information and will make the next pinch pot more stable.