What is Wet Abrasive Blasting?
Wet abrasive blasters can be divided into three general types: slurry blasters, venturi blasters, and vapor abrasive blasters.
A slurry blaster is a dry abrasive blasting machine that adds water at the nozzle, via a water induction nozzle (WIN) or encircles the blast stream with a curtain of water, aka halo ring.
These devices are an inefficient way of dampening the media. Dust suppression up to 80% can be achieved, but requires an extreme amount of water, and creates a big, muddy mess.
Slurry blasting also fatigues the operator, who has to drag around the additional weight of a water hose at the nozzle.
Venturi blasters store water and blast media in the pot. The mixture is sucked out of the pot by the passing pressurized air stream (venturi effect).Similar to the way a carburetor blends air and fuel, the amount of water and media in the blast stream is dependent on the volume of air flow into the system.
While venturi blasters provide good dust suppression, they are only productive at high blast pressures, and use an excessive amount of water and media.
Vapor Abrasive Blasters
Vapor abrasive blasters like the Ecoquip 2 store water and blast media under pressure in the pot. This moist abrasive is injected into the air stream by hydraulic controls, allowing the operator to independently adjust the air pressure and the media consumption rate.
Vapor abrasive blasters can effectively blast at pressures as low as 30 psi - making it ideal for restoring delicate surfaces and removing road markings and graffiti - but can also go as high as 170 psi for heavy duty industrial work and shipyard applications. Vapor abrasive blasters use only as much water and media as the application requires.
Advantages ofWet Abrasive Blasting
1. Wet Abrasive Blasting Produces Less Dust
When blasting, dust is produced by the shattering of the dry abrasive particle and the substrate (in the cases of friable surfaces like concrete) into small, airborne particles. When a wet particle shatters, the subsequent particle is enveloped in a water droplet. The additional mass wieghs down the particle, causing it to fall to the ground. Vapor abrasive blasting has been proven to suppress dust up to 92% compared to dry blasting.
Adding water is wide accepted as the most effective and efficient way to suppress dust. OSHA’s Final Rule on Respirable Silica goes as far as to mandate the use of water in all sandblasting operations.
Less dust is not only safer, but it provides economic benefits as well: it requires much less containment than dry blasting, which translates into big labor savings; it allows you to take on jobs in situations where sandblasting isn’t feasible (within city limits, environmentally sensitive areas.
Contractors vapor abrasive blasting the San Francisco BART alongside a busy city street without containment.
2. Production Rates Equal To or Greater Than Sandblasting
Wet particles carry more mass and deliver more energy when they impact a surface. This means with wet abrasive blasting you can do the same amount of work with a finer grade of media, which translates into more impacts per volume of media - in other words, better scouring power. The job gets done quicker, saving you media and labor costs.
Unlike other wet abrasive blasters, Ecoquip 2 is rated up to 175 psi - delivering as much power at the nozzle as you can handle - enough to blast through the toughest applications.
In a head-to-head test with a dry blasting rig, Ecoquip2 finished the job 45% faster.
3. Wet Abrasive Blasting is Safer
By suppressing dust, wet abrasive blasting greatly reduces the danger of respiratory illness to operators and other workers in the area. OSHA has mandated water as an engineering control to prevent silicosis, but there is much evidence that other abrasives, such as coal slag, are at least as hazardous as silica. Wet abrasive blasting is simply the responsible choice for blasting operations that put employee wellness first.
But wet abrasive blasting makes the workplace safer in other ways. Whereas dry blasting requires full blasting helmets, wet abrasive blasting requires only a respirator, eye and ear protection, which translates into greater visibility, reducing the likelihood of accidents.
Due to reduced containment and workplace restrictions, wet abrasive blasters can operate alongside other trades, improving efficiency.
4. Wet Abrasive Blasting Cleans the Surface
Having a clean surface is essential for a good bond. Before dry blasting, surfaces must be cleaned according to standards. Otherwise, blasting will simply smear oil, grease and other contaminants around the surface, and surface salts that are not removed will cause coatings failure.
Wet abrasive blasting saves you a step by washing away those deeply embedded contaminants.
5. Wet abrasive blasting prevents heat warping
When blasting thin metal surfaces, friction from dry blasting can heat up the metal, causing it to warp.
Wet abrasive blasting keeps surfaces cool, making it the ideal choice for auto restoration and antique metal restoration.
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