Abstract: A method and article of manufacture for providing a mechanical bond and an improved water vapor seal between a lens (11, 41) and a base (17, 47) in an instrument housing (10, 40), includes heating the components and a hot butyl rubber sealant (18, 58) prior to assembly, maintaining a level of heating for the assembly during assembly, dispensing the heated sealant (18, 58) into a channel (25, 65) to form a ring-shaped body of sealant (18, 58), assembling the lens (11, 41) to the base (17, 47) and pressing a lower edge (11a, 41a) of the lens (11, 41) into the ring of sealant (18, 48) and bending an upper edge (17b, 47b) of the side wall (17a, 47a) over a portion (11b, 41b) of the lens (11, 41). The method is applied in a second embodiment to an instrument having at least two signal conductors (55) entering the base (47) at two entry points. Apparatuses manufactured with the method are also disclosed.