How to Adjust Abrasive Blasting Equipment for Maximum Performance?

The design of the abrasive blasting equipment can have a major influence on the surface preparation condition obtained and the efficiency of the blasting. Using properly adjusted abrasive blasting equipment can greatly reduce your blasting time and increase the quality of the finished surface.

In this article, we will learn how to adjust the abrasive blasting equipment for maximum performance.

1.      Optimize the air pressure for abrasive blasting

Optimum abrasive blasting pressure is at least 100 psi. If you use lower pressures, productivity will almost certainly be reduced. And the blasting efficiency drops around 1.5% for every 1 psi below 100.

Make sure you measure the air pressure at the nozzle instead of the compressor, as there will be an unavoidable drop in pressure between the compressor and the nozzle, especially when you use long lengths hose.

Measure nozzle pressure with a hypodermic needle gauge inserted into the blast hose, directly before the nozzle.

When attaching additional equipment, the compressor should be sized appropriately to maintain sufficient air pressure at every nozzle (min. 100 psi).

2. Use a proper abrasive metering valve to ensure optimal consumption

The metering valve is a critical part of the abrasive supply to the nozzle, which precisely controls the amount of abrasive introduced into the airstream.

Open and close the valve by a few turns to ensure accurate metering. Test production rate by blasting on the surface. Too many abrasives can lead to the particles colliding with each other, slowing down the velocity and ultimately affecting the finish quality. Too little abrasive will result in an incomplete blast pattern, resulting in lower productivity as some areas need to be redone.

3.      Use the correct blast nozzle size and type

The bore size of the blast nozzle can directly affect the productivity of the blasting job. The larger the nozzle bore, the bigger the area blasted, thus reducing your blasting time and improving productivity. However, nozzle sizing should be dependent on project specification and air availability. There needs to be a balance between compressor, hose, and nozzle sizes.

Besides the nozzle size, nozzle type also affects the blast pattern and productivity. Straight bore nozzles produce a narrow blast pattern, commonly used for spot blasting. Venturi nozzles produce a wider pattern along with increased abrasive velocity, facilitating higher productivity.

You also need to regularly inspect blast nozzles and replace them if necessary. The nozzle liner will become worn over time and increased bore size will require more air in order to maintain nozzle pressure and abrasive speed. So it is better to replace a nozzle when it is worn to 2mm of its original size.

4. Use the correct blast hose

For blasting hoses, you should always choose good quality and use the correct diameter to minimize friction losses.

A rough guide for hose sizing is that the blast hose should be three to five times the diameter of the nozzle. Hose lengths should be as short as site conditions will allow, and properly sized fittings should be installed to avoid unnecessary pressure loss throughout the system.

5. Check the air supply

You need to regularly check the air supply and make sure to blast with cool and dry compressed air. Moist air can cause the abrasive to clump and clog the hose. It can also cause moisture to condense on the substrate, resulting in blistering that may lead to coating failure.

The air supply should also be free of compressor oil as this can contaminate the abrasive and subsequently the cleaned surfaces.