What is Abrasive Blasting?
Abrasive blasting is when a high-pressure stream of air or water removes paint, rust, or other debris from a surface. It can be used on metal and non-metal surfaces and is often used to prepare surfaces for painting or other forms of finishing. This process is also sometimes used to clean graffiti from buildings or other structures.
Abrasive Blasting is easy to perform and efficient if the correct security measures are in place. There are also portable options, or it can utilize a multiple machines if blast rooms are used, for example. However, abrasive blasting also includes risks if not handled properly. Tiny particles can enter an operator’s lungs and cause diseases like silicosis. Some natural blast media, such as walnut shells or corn cobs, can trigger an allergic response in some people, potentially resulting in anaphylactic shock.
Components of an Abrasive Blast System
Abrasive blasting systems consist of several key components to operate and ensure safety in the workshop. A full set up would ideally include the following :
Abrasive Container or Blasting Pot
The abrasive container, or blasting pot, is a pressure-resistant container that holds the abrasive material and the compressed air used to power the abrasive stream. The blasting pot size will vary depending on the type and amount of abrasive material used.
Propelling Device or Mechanism
The propelling device or mechanism powers the stream of abrasive material. The most common type of propelling device is an air compressor, which uses compressed air to power the stream. Other types of moving devices include electric motors and hydraulic pumps.
Blasting Nozzles
The blasting nozzle is a device that controls the direction and flow of the abrasive stream. Blasting nozzles come in different shapes and sizes, depending on their purpose.
Portable or Mobile Blast Equipment
Portable blasting machines are moveable from one location to another. Trailers usually transport these systems. Some mobile systems use hoppers to hold the abrasive materials. Sometimes, the abrasive materials are recycled after being used, and sometimes they are not.
Blast Cabinets
A blast cabinet allows you to blast an object with high pressure using specially prepared gloves attached to the cabinet. A blasting cabinet protects the user from flying abrasives and dust by placing the object inside.
Blast Rooms
Blast rooms serve the same purpose as blast cabinets but on a much larger scale. They can be big enough to accommodate large objects such as vehicles or airplanes. An object is treated with abrasives in these rooms, depending on the needs of the finished product.
Difference Between Dry Blasting and Wet Blasting
The main difference between dry blasting and wet blasting is that dry blasting uses the impact of the propelled media to affect the surface, while wet blasting uses water propulsion to clean the surface.
Wet blasting is usually the best choice when you want a more refined surface profile. In contrast, dry blasting cabinets need a dust collector to gather and filter the debris from the blasted surface and used media.
10 Types of Abrasive Blasting
1. Sand Blasting
Sandblasting machines shoot tiny beads of dry silica at a high velocity, using either silica or quartz. These particles are incredibly abrasive and can achieve uniform finishes on surfaces. The high-speed particles from sandblasting remove contaminants efficiently, making it a popular method for cleaning rust off metal.
Best used for: Applicable to any surfaces.
2. Wet Blasting
The primary issue with air blasting is the lack of control over the amount of dust that gets airborne. Wet blasting solves this problem. This tool blasts water near the end of the nozzle to push out the abrasive at high speeds. Sometimes, water is mixed with the abrasive before it’s ejected through the nozzle.
Best used for: Surfaces blasted with materials that need to be kept under control, such as preventing dust from flying around.
3. Vacuum Blasting
Vacuum blasting, also known as dustless blasting, is a type of surface cleaning that uses a machine to propel abrasives at a high velocity. The vacuum suction on the machine then removes the propelled materials and any surface contaminants. Vacuum blasting is more effective in recycling spent abrasives and minimizes debris from the cleaning process.
Best used for: Any abrasive blasting that requires little to no debris spillage into the surrounding area.
4. Centrifugal Blasting
Centrifugal blasting, or wheel blasting, uses a motor-operated blade wheel to hurl abrasives at incredibly high speeds toward the surface that needs cleaning. The most substantial advantage of this cleaning method is that it doesn’t use compressed air pressure, making it much safer. Additionally, users have reported that it works more effectively and leaves surfaces cleaner and smoother.
Best used for: Abrasive blasting operations that require high efficiency and throughput over an extended period.
5. Soda Blasting
Soda blasting is a new type of blasting that uses sodium bicarbonate as the abrasive. Using sodium bicarbonate has been shown to remove specific contaminants from surfaces effectively.
Best used for: Softer surfaces that require gentle cleaners.
6. Steel Grit Blasting
Steel grit blasting uses small, round steels as abrasives. It’s often the go-to choice for those trying to clean metal surfaces because it removes paint or rust. Another upside to steel grit is that it can help create a smooth surface finish and strengthen the metal through peening.
Best used for: Perfect for surfaces that require a smooth finish and fast cutting removal.
7. Bristle Blasting
Bristle blasting is a type of cleaning that doesn’t use an abrasive. Instead, steel wire bristles are rotated against the material’s surface to eliminate contaminants.
Best used for: Ideal for uniform finish and greater precision.
8. Dry-Ice Blasting
A newer method that uses high-pressure air and carbon dioxide pellets, dry-ice blasting uses high-pressure air and carbon dioxide pellets. Carbon dioxide is a non-toxic abrasive blasting agent that doesn’t react with surface contaminants, making it ideal for cleaning food processing equipment.
Best used for: Any delicate surfaces that abrasives can’t damage.
9. Pencil Blasting
Pencil blasting, also known as micro-blasting, is a process where high-pressure air and powder are combined. They’re then ejected through a small nozzle, creating a stream that’s both precise and perfect for cleaning particular areas.
Best used for: Any blasting projects that require extreme precision.
10. Bead Blasting
Bead blasting is a method of using air pressure to clean metal surfaces. It uses glass beads that are effective at cleaning and deburring metal surfaces. The glass beads are spherical, and when they impact the surface, they create a micro-dimple.
Best used for: Any surfaces that require a bright smooth finish.
Improve Safety in Construction Operations
Common Safety Hazards
Abrasive blasting may also pose safety hazards if the system is not used properly. For example, dusts created from both the media being blasted and the surface can cause health problems if users are too exposed to inhale the dust particles.
Here are some examples of common safety hazards in abrasive blasting:
- Respiratory Illness: The dust from abrasive blasting can contain harmful materials like silica and lead, leading to serious respiratory conditions. Workers must use suitable respirators during operations.
- Hearing Loss: Abrasive blasting equipment generates noise levels over 90 dBA, which can cause permanent hearing loss without proper ear protection.
- Skin Irritation and Abrasion: High-speed particles can irritate or injure the skin. Protective clothing, including gloves and blast suits, is essential.
- Eye Damage: Microscopic particles can cause severe eye injuries. Safety goggles or blast helmets with visors are necessary to prevent vision loss.
- Air Contaminants: Harmful airborne contaminants may be released during blasting. Monitoring air quality and using ventilation systems are important for minimizing exposure.
FAQs about Abrasive Blasting
Not exactly, they are often used interchangeably but may utilize different materials and have different processes. But sandblasting and abrasive blasting generally describe the similar process: using airborne abrasives to remove the top layer of a substrate, coating, contaminant, or corrosion.
The main difference between dry blasting and wet blasting is that dry blasting uses the impact of the propelled media to affect the surface, while wet blasting uses water propulsion to clean the surface.
Wet blasting is usually the best choice when you want a more refined surface profile. In contrast, dry blasting cabinets need a dust collector to gather and filter the debris from the blasted surface and used media.
A 1974 recommendation from the National Institute for Occupational Safety and Health (NIOSH) recommended that silica sand (or any other substance containing more than 1 percent crystalline silica) be prohibited as an abrasive blasting material because workers are at risk of developing silicosis and risk is difficult to control.
Soda blasting uses sodium bicarbonate, which is also known as baking soda. Compressed air or water propels the soda particles against a surface. Because baking soda is relatively mild, soda blasting is often used instead of harsher methods.
Rob Paredes
