Will using wet abrasive blasting instead of dry eliminate dust?
Firstly, before we answer this question it is important to clear up a common misconception. There is no such thing as a 100% dustless surface preparation method. (For background information on the reasons and methods for surface preparation, see Substrate Surface Preparation for Corrosion Prevention.) All abrasive blasting techniques and equipment (wet or dry) will produce dust. However, air quality tests have shown that wet abrasive blasting (also known as vapor abrasive blasting) can produce up to 92% less dust than dry blasting.
During dry blasting, high-pressure air is used to direct a stream of high-velocity abrasive material towards a surface. When these particles impact the surface, they shatter into numerous fine particles to form dust. The majority of the fine particles disperse into the air and can remain suspended for a while because they lack the mass and density to immediately descend to the ground.
During wet blasting, the abrasive particles are coated with a “water jacket” that adheres to the perimeter of the particle by surface tension. When the water encapsulated particle hits the material's surface, the surface tension holds onto the particles and hinders them from bouncing off the surface. Fine particles that are produced upon impact are also encapsulated and weighed down by the water jacket, causing them to fall to the ground and thus preventing dispersion into the atmosphere.
However, small amounts of dust can still be formed during wet blasting because:
- The mass of some tiny particles may be so light that water may not be enough to weigh them down.
- Some of the finer particles, especially those formed from the dry interior of the shattered parent particle may escape without coming into contact with the water.