The ideal form of the bowling ball can create wrong idea of its uniform structure. The modern professional sphere consists of two main parts: kernel and covering.
The kernel of a usual ball (that used in clubs for hire and is called therefore house-ball) is the sphere, which made entirely of uniform material. The kernel of sports spheres includes the weight block and the filling surrounding that forming the sphere. The weight block can consist of several parts and have the most various forms, depending on a plan of its manufacturer and purpose of a sphere. That is why it is necessary to remember for what style of play do you buy it? The existence of the weight block allows significantly affect the trajectory of the ball movement.
Kernel covering is second important factor. Depending on material of covering bowling balls divides into rubber, plastic, urethane, jet and the proactive.
The rubber covering was the only material till 1959. As wooden paths were softer than modern polymeric analogs rigid rubber ball had good energy and was easily controlled. Now it is almost impossible to buy a new rubber sphere.
Plastic (polyester) has appeared in 1959 as reaction to the development of covering of paths technology. Plastic spheres attracted with a variety of color and relatively low cost. Such spheres are easily controlled on a path of any rigidity and with any drawing. Therefore, plastic spheres are ideal for the beginners and they still perform function of house-bol. At the same time plastic is included into an arsenal of skilled players for performance of direct strokes.
Urethane as a covering of spheres has been presented in 1981. This material is more rigid, strong and wears proof. Spheres with a urethane covering are capable of twisting quicker, than rubber or plastic. They provide good coupling on oil and sufficient friction in a dry zone. Urethane is easily processed that gives to players ample opportunities for individual optimization of a sphere.
Jet spheres appeared in 1991. The covering of these balls is made of complex composite materials with the general name “jet rubber” which provides powerful reaction at the end of a path. Jet balls demand from the player of certain skills as they need stable control. Therefore this type of the ball usually not recommended to beginners. Correct use of this ball provide good results., but unfortunately, they are short-lived – 5500 throws enough for strong absorption of oil from a path in a jet covering and losses of qualities.
Pro-active spheres so far the latest technology of the ball covering. It is made on base the reactive, but with an addition on a surface of the thinnest layer (3-4 molecules) of special material which actively interacts with a path surface in the course of the movement of a sphere. This technology has received the name “particle technology”. It provides even more powerful reaction of a sphere but also demands a bigger experience from the player of knowledge of the equipment. Pro-active and jet spheres – the most expensive and short-lived, but most “productive”. Today all professionals use these spheres for the first throw.