The recessed steel screen fits into the concave head of the blast machine. The operator places one or more bags of abrasive onto the screen and cuts the bag(s) to allow abrasive to flow through the precisely sized holesin the screen to fill the blast machine. The recessed screen can be used with bulk abrasive loading systems. When not in use, the blast machine should be covered to prevent moisture or airborne trash from falling into the pressure vessel. The heavy poly bag cover fits over the entire blast machine to protect the pressure vessel from weather.