a system for applying a uniform band of liquid primer material to the marginal edge surfaces of glazing units upon which a plastic frame or gasket member is to be molded in place . a family of interchangeable applicator tips is provided for use with a dispensing device adapted to provide an on - demand supply of primer material to the tip in use . the different applicator tips of the family have configurations particularly adapted to applying bands of primer material along selected peripheral margins of a sheet member . each is of a composite construction including a relatively rigid base member covered by a soft absorbent body for contacting and transferring to the sheet surface the layer of primer material . the tips are readily attachable to and removable from the primer material dispensing device . the dispensing device may comprise one or more applicator guns incorporated in a modular work station , including a closed storage and supply container for the primer material and a solvent flush system for cleaning hoses and flow guns of the reactive priming resins . the flow guns may be mounted upon an oscillating carriage whereby , in one position of the carriage , spent applicator tips are removed and replaced by new tips by a suitably programmed robot , and in another position the marginal edges of sheet members are moved along and through the applicator tips by a suitably programmed robot arm for application of a band of the primer material .