Abrasive blasting is one of the most effective ways to prepare surfaces for painting, coating, or repair. The technology is based on feeding pressurized air with an abrasive material that strikes the surface, removing rust, mill scale, old coatings, or contaminants.
In practice, three methods are most commonly used: shot blasting, glass bead blasting, and sandblasting. Let’s break down how they differ and why shot blasting technology often prevails.
Sandblasting: Common, But With Limitations
Sandblasting (using quartz sand) is considered the most accessible type of cleaning. Quartz sand is delivered by compressed air and effectively removes dirt, scale, and corrosion.
Pros of Sandblasting:
- Availability of equipment and materials.
- Suitable for rough cleaning of metal, stone, and concrete.
- Quickly removes old coatings.
Cons:
- Sand produces a lot of dust—work requires powerful ventilation and protection.
- Quartz dust is dangerous to health (silicosis, lung diseases).
- High rate of equipment wear.
- The treated surface is rough and may require additional finishing.
Thus, sandblasting is suitable for “rough” cleaning but is often insufficient for precise and high-tech tasks.
Glass Bead Blasting: Delicacy and Precision
Glass bead blasting is used where scale or oxides need to be carefully removed without damaging the surface. Glass microspheres (beads) are used as the abrasive.
Pros of Glass Bead Blasting:
- Gentle effect; the surface is not damaged.
- Gives the metal a decorative, matte finish.
- Suitable for stainless steel, aluminum, and non-ferrous metals.
- Used in mechanical engineering, medicine, and the food industry.
Cons:
- Less aggressive cleaning; cannot cope with thick rust.
- Abrasive cost is higher than sand.
- Requires a sealed blast cabinet for operation.
Essentially, glass bead blasting is a “fine polish” for surfaces where aesthetics and precision are required.
Shot Blasting: The Leader in Efficiency
Shot blasting is a method that uses metal shot (steel or cast iron) as the abrasive. A high-pressure stream of shot literally “knocks” contaminants off the surface.
Advantages of Shot Blasting:
- Maximum Efficiency. Removes thick layers of rust, mill scale, bitumen, and paint coatings.
- Surface Hardening. The impact of the shot causes a peening effect, making the metal more resistant to fatigue loads.
- Cost-Effectiveness. The shot can be reused many times (unlike sand).
- Process Cleanliness. Less dust is generated because the shot is heavy and settles quickly.
- Versatility. Used for preparing metal structures, machine parts, pipeline fittings, ships, and storage tanks.
Disadvantages:
- Requires more powerful equipment.
- Higher initial investment than sandblasting.
However, in the long run, shot blasting proves more cost-effective: lower abrasive consumption, higher productivity, and better surface quality.
Comparative Table of Abrasive Technologies
Why is Shot Blasting Better Than Sandblasting?
- Safety. No quartz dust, which is dangerous for the respiratory tract.
- Savings. Shot lasts longer—one batch can be used for dozens of cycles.
- Quality. The surface becomes not only clean but also stronger.
- Productivity. Cleaning speed is higher, resulting in savings in time and labor.
For example, if you need to clean an old metal tank from a thick crust of rust, sandblasting will work, but the sand consumption will be huge, and the surface will remain porous. Shot blasting will do it faster, cleaner, and ensure the metal’s longevity.
Abrasive blasting is not just about removing contaminants but comprehensive surface preparation. Glass bead blasting is ideal for decorative and fine work, sandblasting is suitable for rough and budget-conscious tasks, but if durability, efficiency, and safety are paramount, the undisputed leader is shot blasting.
The choice of method depends on the specific tasks, but in industry and construction, the shot blasting technology is increasingly preferred.