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Buy wet blast machines – Use water addition strategically for the blasting process

Wet blast machines combine compressed air, abrasive media, and water to clean surfaces, remove rust, strip paint, or prepare surfaces for subsequent coating. The addition of water binds a large portion of the dust generated during blasting directly to the blasting stream or at the point of impact. For this reason, the process is particularly used in situations where open dry blasting would result in high dust exposure or increased cleaning effort.

Wet blasting and water blasting are often used as related terms in the market. Technically, the key factor is not so much the term itself as the method of water addition and the coordination of air pressure, abrasive flow rate, and water flow. Too little water reduces dust suppression, while too much water unnecessarily saturates the process, generates wastewater, and can increase the risk of rapid corrosion on bare steel.

Complete wet blast systems for high blasting performance

Complete wet blasting systems with blast pots are available for intensive professional applications. The current product range includes systems with vessel capacities of 25, 50, 100, 140, and 200 liters. Larger vessels primarily increase the abrasive supply and extend the time between refills. The actual blasting performance is largely determined by nozzle size, operating pressure, and available compressed air.

Larger wet blast systems use, among other things, 9.5-mm blast nozzles. This significantly increases air consumption: for some systems, it is already around 5 m³/min at 6 bar. The compressor must therefore not only meet the nominal nozzle demand but also account for line losses and provide sufficient power reserves.

Wet, low-pressure systems for more delicate surfaces

Wet, low-pressure systems can be useful for restoration, graffiti removal, natural stone, facades, or other sensitive surfaces. They allow for finer adjustment of blasting pressure, abrasive flow, and water addition. The product line includes mobile systems with an integrated compressed air supply and their own water supply, which are specifically designed for use at varying locations.

However, low pressure alone does not guarantee gentle processing. The hardness of the abrasive, grain size, distance, and dwell time also influence material removal. For sensitive or unknown surfaces, you should therefore start with moderate settings and check the results on a test area.

Retrofit existing blasting equipment for wet blasting

A completely new system is not always necessary. Suitable blasting systems can be upgraded to include controlled water injection using wet blast pumps, wet blast heads, or wet blast nozzles. The product range includes pneumatic pumps with flow rates of up to approximately 15 or 16 liters per minute. Depending on the system, water can be added directly at the nozzle or within the blast hose.

Adding material near the nozzle allows for precise adjustment at the work area. If the abrasive media is moistened while still in the blast hose, dust can be bound even during material transport. Which option makes sense depends on the blasting system and the specific application.

Adjust the abrasive media, water, and pressure together

To achieve reproducible results, all process parameters must be properly aligned. The abrasive media must be suitable for the equipment, metering valve, nozzle, and surface. The water volume should be set only as high as necessary for dust suppression and surface treatment. The working pressure and abrasive media flow rate are then adjusted to achieve the desired cleaning or material removal performance.

For metallic surfaces, further treatment must be considered after wet blasting. Depending on the material, water quality, and environmental conditions, flash rust can form quickly on freshly blasted steel. The subsequent cleaning, drying, or coating should therefore be included in the process planning.

Buy a wet blasting system – don’t underestimate the importance of compressed air supply

Anyone looking to purchase a wet blast machine should plan for the compressed air supply from the very beginning. Nozzle size and operating pressure have a much greater impact on air demand than the size of the air receiver. A compressed air supply that is too small leads to pressure drops and fluctuating blasting performance.

Information regarding the surface, desired result, daily operating time, abrasive media, available compressor power, and desired mobility will help you make your selection. Based on this information, you can determine whether a complete wet-blast system, a low-pressure wet blasting unit, or a retrofit solution for your existing blasting equipment is the more cost-effective option.