a method for making tubular plastic material having shaped interlocking profiles thereon for use in reclosable bags by cross - cutting and sealing the material to form the individual bags . the tubular material is made in different diameters of tubes to form bags of different depths , and the speed of delivery of the plastic material and the rate of inflation and delfation is controlled to determine the diameter of the tubing , while the plastic delivery to the profile portion of the die is separately controlled and maintained at a rate , so that , for different sizes and gauges of tubing , the profile will be maintained constant thereby obtaining a profile of optimum size and providing for bags which can be varied in size , but which can each accommodate the same closing and opening slider which fits over the profiles . this method of extruding profile tubes requires fewer changes in extrusion dies .