The dust collector slide gate should be set so that enough air flow is drawn through the abrasive curtain to remove most of the fines and other contaminants. The air flow or suction created by the dust collector will cause the abrasive curtain to bend towards the lower separator lip. If adjusted properly, fines and dust are pulled over the lower separator lip and gravity fed to a waste hopper. Clean abrasive should hit near the top of the lower separator lip and drop into a collection hopper for re-use. . A good working mix contains a well-balanced distribution of large, medium and small abrasive particles.
Large particles perform the major task of loosening the thick, heavy contaminants.
Small particles provide the coverage necessary for the efficient removal of lighter coatings, mill scale and rust. Smaller particles also perform the important task of thoroughly cleaning and scouring pits. Establishing a suitable range of particles in the working mix is application-specific and is based primarily on the profile requirement and the coating or contaminant to be removed. Typically, garnet particles smaller than 80-90 mesh should be extracted from the working mix when removing coatings over 20 mils or medium rust. For blast applications removing light rust, mill scale, primers and thin coatings, the working mix can be broadened to include 100, or even 120, mesh garnet particles.