To insure a correct reading by the gauge, the NIST standards are used to verify accuracy. The hypodermic needle pressure gauge indicates whether or not the pressure at the blast nozzle is in the optimum range. A 10-pound pressure loss results in a 15 percent loss in productivity. The blast nozzle aperture gauge is used to measure the throat diameter of the blast nozzle. Abrasive blasting erodes the inside of the blast nozzle, resulting in reduced abrasive velocity and a greater volume of compressed air.
Productivity varies directly with particle velocity.
Many times, these instruments can be purchased in a kit form that is less expensive than purchasing each instrument separately. The important thing to remember is that these instruments are going to provide you with a means to verify that you have met the specification requirements. Another plus is that your company will gain a reputation of being knowledgeable and easy to work with. Coatings inspection instruments may be purchased from distributors or companies specializing in this specific instrumentation. Many firms advertise in trade journals or are listed in the Thomas Register.