seam area when under stress the basic fracturing ball constructed according to the present invention is a single core two layer design however the present invention anticipates ball construction comprising several cores and layers these cores and layers can be made from but are not limited to plastics rubbers glass fibers carbon fibers zinc alloys and aluminum alloys using dissimilar materials for construction facilitates the creation of a ball with ideal fracturing properties for a given borehole drilling environment the target properties that make a fracturing ball function optimally are a strong resilient able to withstand high pressures b pliable for sealing against the ball seat c easily machinable for removal from the pipe d corrosion resistant and e a specific gravity higher than the frac ball carrier or fracturing fluid to insure that the ball and any ball debris will float additionally the core and the layers should adhere well to one another to minimize the possibility that the ball may distort and fail when under stress the basic multilayer designs of the frac ball 40 of the present invention according to the embodiment shown in fig3 are preferably made up of a g 10 or other related phenolic plastics core 42 a two part epoxy inner layer 48 and a 6013 t8 aluminum or similar outer layer shell made up of hemispherical shell halves 44 amp 46 in the embodiment shown in fig3 the.