Our competition petanque boules are hollow. These are the steps of our manufacturing process: - A lump of steel heated to +/- 1000 C° is flattened and then stamped or forged into a hemisphere - These hemispheres are machined inside, welded together, and rotated until they are spherical. - The boule is then engraved, baked, and dipped into water, which will determine its hardness. - Finally, they are polished or varnished and then inspected.