How to make clay projectiles
Clay projectiles can be made with various methods. They all have in common that the clay is first portioned according to the desired weight of the resulting projectile. Note that, as clay dries, it looses some of its weight and shrinks somewhat. The weight of a dried projectile is only about 80% of the initial weight.
With some practice, the common biconical shape of sling projectiles can be achieved very quickly using a wooden board. For that, put a portion of the clay on a smooth surface. Gently press the wooden board on the clay and perform circular motion. By that, a double cone emerges, which can then be brought into its final shape by hand. The linked video shows this method in action: https://www.youtube.com/watch?v=51EpUZA_a7o.
Just as beautiful results can be achieved with press molds, which do not require as much practice. A kitchen mold for making Kibbeh, a dish popular in Middle East, is well suited for this. The pieces of clay are simply put into the pans of the mold and are then pressed into shape by closing it. To remove the finished projectiles more easily from the mold, put a piece of plastic wrap inside the mold beforehand. This kitchen mold can even produce hollow clay projectiles. If you add a hole with a sharp edge on the surface, they will whistle during flight, similar to an ocarina.
More varied shapes and weights can be made with a custom made press mold. A 3D-printer is very helpful for that.
