Wet blasting: when to choose it over dry

In dry blasting, the abrasive is accelerated by compressed air or by a wheel. In wet blasting, it is carried by a pressurised water jet.

Changing the medium changes the character of the process completely.

What it does differently

Dust leaves the equation. Water binds the fine particles. There is no dust cloud, and therefore none of the respiratory exposure problem that dominates dry blasting.

The attack is gentler. Water damps the impact. The base material is stressed less and surface deformation is smaller.

Fine particles become usable. In dry blasting, very fine abrasive creates dust and is hard to control. In a wet medium, it works efficiently.

Oily parts can be cleaned directly. Water with additives washes at the same time as the abrasive works.

When to choose it

• Delicate surfaces — thin parts, soft alloys, components that cannot take an aggressive dry blast
• Fine finishes — where a uniform matt appearance without a deep profile is required
• Parts contaminated with oil or grease — cleaned and blasted in one operation
• Parts with hazardous contamination — the wet medium retains particles instead of dispersing them
• When dust is the main problem — in spaces where extraction is hard to arrange

What to account for

Parts come out wet. They must be dried, and carbon steel protected against corrosion immediately. Additives in the water can partly cover this.

Water has to be managed. Recirculation, filtration, settling. That is one more system alongside the blasting equipment.

Components are stressed. Pumps work with abrasive-laden water and must be abrasion resistant.

Throughput is different. Wet blasting is generally not the choice for maximum productivity on robust parts in high volume. There, the wheel remains the answer.

How to decide

The question to ask is: what bothers you more about dry blasting?

If it is the dust, wet blasting removes it. If it is aggressiveness toward the part, it reduces it. If neither is a problem, dry blasting stays simpler and cheaper to run.

Related reading

• Compressed air Blasting
• Controlling dust in blasting: enclosure, ventilation, protection
• Blast Cabinet