This article is a comprehensive guide that will tell you how to retrofit a pressure delivery system into a suction blast cabinet.
If you purchased a pre-owned suction blast cabinet, or if you are considering converting your suction blast cabinet into a pressure blast cabinet, this guide will help you to understand the conversion process.
If you have not purchased your cabinet yet, read our article Blast Cabinet Delivery System: Suction or Pressure to understand the pros and cons of each system in order to make the right decision at first, as the conversion work can be costly and complex to achieve.
Basically, a pressure blast cabinet has additional components which are not required in a suction blast cabinet:
- Blast pot (pressurized vessel) which contains and propels abrasive media – Adding the blast pot to your existing cabinet is the most critical part. The blast pot is usually fitted under the media reclaiming system or the blast cabinet. Abrasive media usually falls by gravity into the blast pot, so it needs to be at the lower end of your media collecting system. It sometimes involves significant modifications in the frame of the cabinet to be able to fit this component.
- Abrasive metering valve which controls the media flow that enters the airflow – The abrasive metering valve allows you to control the quantity of media that enters the blast stream. It is usually a fairly small and low-cost component that goes right underneath the blast pot.
- Three-way foot pedal which operates the blast nozzle – The three-way valve controls both the airflow and the metering valve. Some suction blast cabinets come with a two-way foot pedal, so only a small valve upgrade is required. Otherwise, the addition of a foot pedal involves changing the entire blast nozzle assembly, and this adds to the cost quite significantly.
- Foot-operated blast nozzle – Basic blast cabinets usually come with a trigger-operated blast gun. Pressure blast cabinets use a blast hose fitted with a nozzle (like traditional sandblasters). However, some suction blast cabinets come with a foot-operated blast nozzle, so the upgrade could be important or irrelevant.
- Manifold to control the blasting operations – The air manifold involves a few pipes and coupling to connect and operate the right components.
- Blast nozzle which is suitable for pressure blasting operations. To take full advantage of the pressure delivery system, and most importantly, to be able to withstand the aggressive friction of a pressure system, it is usually recommended to opt for a durable blast nozzle material such as Tungsten Carbide or Boron Carbide. Most suction blast cabinets come with a ceramic nozzle that would wear out very quickly with a pressure blast cabinet.
Upgrading the suction delivery system into a pressure system involves the addition of all of these extra components to your blast cabinet, when possible. It also involves modifying the blast cabinet’s housing by piercing additional holes in order to fit new hoses and fittings inside.
Finally, if you want to take full advantage of a pressure blast cabinet, you will need additional air pressure (pressure blast cabinets require a minimum of 25 psig to operate and consume more air to maintain the pressure).
Modifying your blast cabinet on your own is not recommended. Leave it to your OEM (Original Equipment Manufacturer) to ensure an optimal retrofit and make sure your pressure blast system will operate steadily without any air leaks and/or pressure loss.