Cut through your clay portion before wedging. If its center and edges have different firmness, preparation needs to address that uneven moisture before you try to center it on the wheel.
Use a dedicated preparation surface
Use a secure surface at a workable height, clear of glaze residue, hard fragments and unrelated craft materials.
Do not add dry powder to sticky clay casually: that changes the formulation and introduces dust. Follow the supplier’s moisture-adjustment guidance and wet-clean the preparation area before crumbs dry.
Assess the clay before choosing the job
Inspect the cut faces. Reclaim and stored bags can contain firm areas beneath a soft surface. Bring excessively wet or stiff clay to workable consistency rather than forcing it through repeated wedging.
Work with the amount needed for your practice piece and seal the rest of the bag. The wheel’s maximum centering rating is not a useful target for a first cup.
Learn one controlled movement
Ask an instructor to demonstrate ram’s-head wedging or another basic method. Watch the hand position and how the clay rolls, then practice slowly enough to inspect each movement.
Avoid folding cavities into the mass. Cut and inspect it again to check consistency; a fixed count of pushes cannot tell you whether the clay is ready.
Portion, cover and move to the wheel
Weigh or otherwise identify the prepared piece for the project you intend to practice. Shape it into a compact lump without a large cavity underneath and cover it if it will wait before throwing. Prepare only as many portions as you can protect from drying during the session.
You will still need to center the prepared portion. If a pull hits a firm streak, examine the clay rather than increasing speed. Note whether the problem occurs with fresh clay, reclaim or both.
Questions about this topic
Do I have to wedge a new bag of clay?
Inspect and follow the clay supplier’s advice. Commercially prepared clay may need less work than uneven reclaim, but a new bag is not proof that storage has left every portion identical.
How many times should I wedge?
There is no useful universal count. Learn a controlled technique and check consistency; unnecessary repetitions do not guarantee better clay.