An applicator, for applying a glutinous substance to a seam between a first part and a second part, comprises a roller, comprising a circumferential surface, and a housing, comprising a delivery port, a scraper, and a shaper. The roller is coupled to the housing and is rotatable relative to the housing about an axis. The circumferential surface of the roller is communicatively coupled with the delivery port. The intersection of the circumferential surface and a virtual plane, passing through the axis, is a non-linear segment. The scraper is geometrically complementary at least with the non-linear segment. The shaper is communicatively coupled with the scraper.