A welding power supply for supply of current to a welding electrode, and a method and a computer program for controlling such a welding power supply is described. The features are formed by defining a first mask through one or more layers of a multilayer stack formed on a substrate. The inner core is preferably a pre-formed selectively weighted symmetrical, but non-spherical insert, which may be made from either a high or low specific gravity material to control the moment of inertia and spin rate of the ball. The compound can help to keep defects from propagating, improve fracture toughness, and reduce the likelihood that a crack will form during subsequent fabrication or use of the transparent body.