Wetblast machines are not all created equal

A common misconception is that all wetblast machines are the same, give the same finish and operate the same way. In fact, there are several methods of getting air, water and media to the process gun. Another complication is that the open systems such as those used for graffiti removal and on boats use similar terms but mean entirely different processes such as the use of high-pressure water which the Dana-Ridge process does not use.

The Dana-Ridge wet-blasting process offers many advantages over the regular dry sandblasting method. They’re more environmentally friendly and less hazardous to user health with its dustless operation. Also, there’s no need for an expensive filtration system. You can blast with finer or coarser media than a dry blaster and blast items that would get destroyed in a regular sandblaster.

Its one-step cleaning and blasting process it eliminates the need for component pre-cleaning and degreasing and you don’t have to worry about leaving fingerprints behind when you touch the brilliantly finished part.

You’ll see terms such as “wet-blaster, vapour honer, vapour blaster, vapour matting, slurry blasting” and more. This can cause some confusion and leaves some new wet-blast cabinet owners wondering why they can’t get the same finish as the contract blaster they used to take their parts to (who was likely using the Dana-Ridge wetblast process).

Venturi

The venturi system is also common on a lot of dry sandblast cabinets and processes.

It uses a principle where air or fluid is passed through a constrictor increasing its velocity and creates negative pressure. This allows a second fluid to be drawn into the flow.

This is useful in blasting as the material is thrown at the part with great speed and has the added benefit of drawing more media up behind it creating continuous flow as it is recycled back to the hopper.

Advantages

• A cheap setup
• Eliminates the dust issue inherent in a dry system
• Can handle finer abrasives

Disadvantages

• Inefficient process
• Inconsistent flow
• Poor concentration of media in the slurry
• Larger volumes of air required to lift media to the gun.
• Finish is OK. Not great

The Pressure Pot System

A second system (also popular in dry-blast cabinets) is the pressure pot system. Here the slurry is directed to a pressurised “pot” using a small pump and the air pressure inside the pot provides the force that sends the media to the process gun where it is further accelerated using compressed air.

Advantages

• More efficient method than the venturi method
• Multi-gun operation is possible

Disadvantages

• Prone to blockage
• Provides an inconsistent flow and concentration
• A higher volume of air is required as it is the main motive force in the system

Vapour blast

Vapour blasters use a pump that both stirs and sends the media slurry to the process gun. The motor is outside the unit while the pump is inside the sump and samples the agitated slurry

Advantages

• Better flow and concentration of media compared to venturi and pot systems.
• Up to two guns per pump

Disadvantages

• Not as efficient as the Dana-Ridge Wetblast System as it is sampling from inside the sump rather than a common collection point

Dana-Ridge Wet-blast Cabinets

Using the method of pumping from a common collection point at the bottom of the sump they are able to maintain a consistent flow to the gun. Some of the flow is also redirected down into the sump to agitate and stir the slurry meaning better concentration.

An air-jet inside the process gun provides the acceleration to provide a superior finish.

The benefits of the Dana-Ridge Wetblast System

• Provides a superior finish
• Uses a high volume, low pressure pump allowing multi-gun operation
• Air used only to atomise to obtain desired degree of aggressiveness of blasting.
• Pump simultaneously provides sump agitation
• Allows for both gentle or aggressive blasting with control over the air supplied to the process gun.
• Little to no damage to more delicate parts. No heat-damage.
• Recirculation of media giving long life and reduced costs.
• Multi-gun system fed from single pump so uniformity of flow and concentration are maintained.
• Bonus is simultaneous degreasing and rust inhibition.
• Long working life from the glandless urethane-lined pump
• Maximum use of space in the hopper as the pump is mounted to the back of the machine. This also allows ease of access for maintenance.
• Using its scrubbing action, contamination, surface deposits, scale or burrs are quickly removed and carried away, leaving a very clean and smooth surface.
• They are commercial grade machines able to operate hour after hour in a busy workshop.