The fluid section of an air operated double diaphragm pump 10 consists of two fluid housings 12, an inlet manifold 14, and an outlet manifold 16. The housings are to be made in two parts. The preferred frame 18 material is glass fiber reinforced with polypropylene that is overmolded into final shape with an encapsulating material 20. The frame 18 is designed so that the encapsulating material 20 can flow from one side to the other allowing for a mechanical lock between the top surface 22 and the bottom so as not to rely on chemical adhesion between the two materials.