You're using the wrong clay
Not every clay is equally suitable for wheel throwing. Especially if you are still a beginner, choosing the wrong clay might make things unnecessarily difficult. A clay that is too weak will collapse as soon as you work it for too long. And a clay that is too hard is difficult to work with. So choose a clay that has a nice balance.
Your clay is not wet enough
Do you feel the clay getting drier and drier while you’re centring? Then you’re not using enough water. Periodically get your hands wet, or add water to your clay with a sponge. If you do use a sponge, make sure you squeeze it slowly to add the water very gradually. This helps you avoid accidentally adding too much water, and that is harder to correct.
Your clay is too wet
Clay that is too wet becomes sticky and does not hold its shape well. Of course that makes centring very difficult. But don’t worry, you can remove the excess water by kneading your clay again. Or if that is not enough, you can also let the clay dry on a plaster slab.
Your clay does not have an even consistency
Many potters don’t particularly enjoy kneading the clay. It requires quite a bit of time and effort, and it is very repetitive. That makes it tempting to skip this step and immediately throw your clay on the wheel. But if you do, you run the risk that your clay does not have an even consistency. And these variations in consistency make it a lot harder to centre the clay. At the end the day you lose more time struggling to centre your clay than you would have lost if you simply kneaded the clay properly in the first place.
Your clay has air bubbles
You don’t just knead to even out the consistency of your clay: it also removes air bubbles. So if you have not kneaded your clay enough and there are still air bubbles in it, you will notice that during centring. Air is lighter than clay, and that difference in weight makes it extra difficult to centre your clay correctly. So kneading thoroughly is crucial!
Another little tip: make sure the clay you throw on your potter’s wheel has a nice, rounded shape. Because if it has a flat bottom, there is a chance that air bubbles will get trapped between the wheel and the bottom of the clay.
You're holding your elbows too high
Finding the right posture behind your pottery wheel makes all the difference. And you probably know that, but once you’re trying to focus, your elbows might drift upwards anyway. It’s a common rookie mistake! And it makes you feel like you don’t have the strenghth to control the clay. So try to anchor your arms against your legs or against your sides from the start.
You're pushing too hard on the clay
Some beginners have a hard time centring because they basically have the clay in a choke hold. If you try to push the clay too forcefully, you may inadvertently push it away from the center.
Centring clay is a gradual process. It takes time and practise. Rather than brute strength, you’re using your bodyweight, and your hands are steering the clay rather than pushing it.
You push the clay out of the centre when you let go
You feel the clay in your hands and you are sure: it’s perfectly centred. But when you let go, it shifts and you have to start all over again. You’re not the only one, it’s a mistake every potter has made. For this, practice really does pay off: with each creation you make, be sure to lift your hands very slowly.
Not sure? Do the test!
It is not always easy to sense whether your clay is actually centred correctly. Luckily there’s an easy way to check. Take a sharp tool and hold it very gently against the side of the clay. Keep your hands in the same position and let your wheel spin. If you see a thin line forming all around, that means your clay is well centred. If you get a thick line on one side only, then you need to make some adjustments. Just keep trying!
