Apparatus is disclosed for controlling the depth of a layer of a layer of adhesive on a peripheral surface of a rotary member (e.g., a wheel) for the application of the adhesive to an object. The apparatus comprises a heated reservoir containing a supply of hot melt adhesive maintained within a desired temperature range, where the rotary member is partially immersed in the adhesive and is rotated by a motor such that the as the rotary member is rotated up out of the peripheral surface of the rotary member has the layer of adhesive thereon. A computer controls system controls the motor such that the speed of the rotary member may be increased or decreased so as to vary the depth of the adhesive on the peripheral surface of the rotary member.