Abstract: A device for applying a thin layer of joint compound to the inner and outer surfaces of a corner bead. The device includes a hopper for supporting a quantity of joint compound. The hopper has two openings which are aligned with one another and have a cross-sectional configuration corresponding to that of a corner bead. The device includes rubber panels for closing off a selected portion of the openings. In use, a corner bead is inserted through one of the openings, pushed through the hopper where joint compound adheres to the bead, and is extracted from the other opening. The rubber panels scrape off all but a thin layer of joint compound from the concave surface of the bead and forces the bead against the bottom of the hopper so as to permit only a thin layer of joint compound to remain on the convex surface of the bead.