Industrial sandblasting is a high-risk, high-reward venture. The Occupational Safety and Health Administration (OSHA) warns unprotected exposure to abrasive blasting materials causes lung damage and cancer, while exposure to blast action noise risks hearing loss.
Conversely, industrial sandblasting reliably improves machine performance by removing rust and scale, preparing machine surfaces for protective coatings, removing debris, and enhancing machine parts’ function and aerodynamism. It’s no surprise economists value the industrial sandblasting services market at $12.1 billion!
When is sandblasting the right choice for your industrial machinery?
What Is Industrial Sandblasting?
According to the engineering manual Quality Analysis of Additively Manufactured Metals, “Sand or bead blasting is an abrasive blasting method, which consists of propelling a high pressure stream of abrasive material (sand, fine beads of plastic or glass) over the surface of the part.”
The broader category of abrasive blasting is described in the textbook Surface Treatment in Bonding Technology like this:
“Abrasive blasting is one of the surface treatment methods involving the use of loose abrasive media with high kinetic energy (developing velocity of approximately 100 m/s)…The process is controlled by several parameters, including the blast angle and cutting properties of abrasive media (e.g. edge sharpness, hardness, and impact resilience). These parameters are crucial to the surface finish and effectiveness of the process.”
To summarize, abrasive blasting is the use of a powerful propellant—usually pressurized air—to force a narrow stream of fine, solid particles over an industrial surface or machine part.
How Does Sandblasting (and Other Media Blasting) Work?
Sandblasting works using specialized equipment to propel blast media against a surface in a narrow, highly-pressurized stream. This creates extreme friction between the blast media and the surface it’s sprayed against, effectively scouring the surface.
The intensity of the blast-stream allows for a significantly stronger scouring force than it’s possible to generate scouring by hand.
Industrial abrasive blasting requires unique equipment. It typically involves:
- A high-powered air compressor
- More rarely, pressurized water is used instead of air
- In those cases, the process is called “wet blasting”
- More rarely, pressurized water is used instead of air
- A blast vessel
- This holds the abrasive media (i.e. sand) and can pressurize it using air from the compressor
- Appropriate hoses, pipes, valves and fittings
- This allows users to direct and alleviate pressure as needed
- A blast nozzle
- This should be replaced periodically, as the abrasive media can damage widen its orifice over time (making the blast output harder to control)
To engage in industrial abrasive blasting safely, professionals use appropriate PPE, including blast suits, guarded boots, gloves, eye-goggles, and hearing protection.
What’s The Function of Sandblasting (or Other Media Blasting?)
Abrasive blasting is most often used to clean or maintain an industrial surface, or to prepare it for finishing, painting or specialized coatings.
Sandblasting, in particular, is most frequently used to remove rust and oxidation from iron-free metals.
Preparing a Surface For Adhesive or Coating
Sandblasting effectively prepares industrial machine surfaces, walls, flooring for adhesive coating in three ways:
- It clears away any buildup of grease, oils, dirt and grit from the surface
- This ensures no grit or “gunk” winds up trapped beneath the coating
- Trapped grease can negatively impact the coating’s efficacy or machine function
- This ensures no grit or “gunk” winds up trapped beneath the coating
- It roughens the profile of the surface
- This improves the surface’s ability to “grip” adhesive coatings
- Rougher surfaces have a greater surface area on a micro level (due to the small “peaks and valleys” composing the rough texture)
- This increases the friction and enhances the “interlocking” mechanic necessary for adhesion
- This improves the surface’s ability to “grip” adhesive coatings
- In contrast, smooth surfaces are more slippery, so coatings slide away more easily
- It evens out severe bumps or bulges
- This makes it easier to apply coatings and finishes
- Surface flatness also improves the aerodynamism of moving machine parts after they’re coated
- Aerodynamic parts move with less friction and function smoothly
This is tactic is used most frequently to prepare metal and concrete surfaces.
Removing Rust
Sandblasting can be used to remove rust by force. Essentially, it tears away the rust but by bit, until the metal unaffected by corrosion is revealed.
Industrial blasters may need to remove more than one layer of rust to get to the corrosion-free layers beneath the surface.
Removing Verdigris and Related Corrosion
Abrasive blasting with sand specifically is often used to remove the visible corrosion, discoloreation, and verdigris from iron-free metals and alloys. Like rust, these are effects of oxidation and water exposure over time. They can also result from galvanic corrosion.
Sandblasting vs Other Abrasive Media
It’s more common to use other media instead of sand when utilizing abrasive blasting to remove rust from iron and iron alloys.
Certainly, sandblasting is sometimes used to de-rust cast iron or steel. But, it requires extreme caution
The heat generated by the extreme friction can easily cause a ferrous surface to warp, or accumulate dings and dents, if sand is blasted against it for too long.
Thus, most industrial cleaners prefer to remove rust via abrasive blasting utilizing other media, which generate less friction and heat in the process. These can include steel grit, glass beads, walnut shells, aluminum oxide, and specialized synthetic materials.
Blasting Away Existing Finish
Sandblasting can be an effective method of removing the finish from industrial parts that need an upgrade. This includes:
- Stripping paint
- Clearing away acrylic, resin or epoxy coatings
- Scraping off caulk and similar sealants
- Scouring off ceramic-based patinas
- Removing chrome plating
Note that certain types of plating (i.e. gold plating) as well as any coating on a material prone to warping, are better removed using other means.
What Tools, Equipment and Machinery Benefit From Sandblasting?
In manufacturing facilities, auto plants, machinist shops, and garages servicing a range of vehicles and agricultural machines, the core equipment requires regular cleaning, maintenance, protection, and upgrades.
As a result, sandblasting and related abrasive blasting is a task that needs to be performed periodically. What types of equipment benefit most from the practice?
Heavy Duty Machinery Requiring Rust Removal
Heavy-duty machinery made of iron or its alloys, exposed to air, will inevitably rust.
Using strategic sandblasting (or abrasive blasting with other media) regularly will prevent rust accumulation and keep the equipment in use longer.
Sandblasting is also a useful rust removal tactic to maintain cast iron stoves, vises, and similar industrial tools. However, some ironworkers prefer abrasive blasting with sodium bicarbonate or glass beads rather than silica, to protect against warping.
Interior Brick Fireplace, Oven or Kiln
Sandblasting is a popular method to engage in abrasive cleaning and surface preparation of masonry.
Notably, unique building codes and fire codes govern brick maintenance (as well as any kind of oven / kiln maintenance). A professional should be able to tell you whether abrasive blasting meets industry or legal standards when cleaning brick in your region.
Brass and Copper Locks, Marine and Automotive Machinery
Non-ferrous metals don’t rust. But, they can experience corrosion and, in certain circumstances, accumulate verdigris. Moreover, brass and copper parts, tools, and devices can become gunked up with oils, grease and particulate debris.
Sandblasting is an effective choice to clean, maintain and prepare the surfaces of these brass and copper materials. In fact, the efficacy of abrasive blasting for brass has made it a popular choice among shipyards.
For example, U.S. Navy shipyards utilize abrasive blasting to clean or prep disassembled ship parts (including brass propellers and components). Notably, Naval shipyards switched to a less-hazardous alternative to silica-sand media in 1983.
Titanium, Tungsten, and Aluminum Equipment
Non-ferrous metals like titanium, tungsten, and aluminum carbide are popular compounds to use in the manufacturing of complex equipment.
Tungsten, for example, is an extremely strong metal used in automotive engines and manufacturing build plates. Aluminum and its alloys are frequently used for parts of manufacturing robots. Meanwhile, titanium is the prime material used to create chemical and heat exchange equipment, aircraft frames, and satellites.
Sandblasting is a crucial, standardized, and highly regulated process in aeronautics and aerospace engineering.
Cleaning, surface preparation, and corrosion combat all engage abrasive blasting within these vital industries. NASA, the FAA, and similar agencies detail the specific ways sandblasting and glass bead abrasion should be used when preparing equipment made with these materials.
Steel and Iron Alloys
Machine parts made from steel and Iron Alloys can benefit from sandblasting under specific circumstances. However, abrasive blasting utilizing other materials offers greater benefits in most cases.
What NOT to Sandblast
It isn’t safe or wise to use sandblasting on all materials.
Other forms of abrasive blasting are used more frequently on ferrous metals and non-metal materials. These other types of blasting are sometimes collectively referred to as “media blasting.”
Moreover, chemical peeling and stripping are better options for certain materials and processes than media blasting. In general, it isn’t wise to use sandblasting, nor most types of abrasive blasting, when cleaning or preparing the following parts and materials:
- Wood
- Glass
- Discrete parts of a car or tractor drivetrain
- Small, fragile, or intricate machine parts
- Iron or iron alloys that have already experienced warping
- Anything coated in lead-based paint
- Combustible materials (magnesium, etc.)
- Precious metals (silver, gold, etc.)
- Any component with delicate details that must be maintained
- Any surface that must stay smooth
- Fabrics
- Soft to mid-soft stone (limestone, etc.)
- Salts (chlorides) and silicas
Sandblasting Alternatives
When sandblasting isn’t the best choice to clean, maintain, or prep industrial equipment and surfaces, it’s time to explore other options. The most utilized alternatives are: soda blasting (or, fine media blasting), chemical stripping, machine stripping, and laser ablation.
Soda Blasting / Fine Media Blasting
Soda blasting is similar to sandblasting, but it uses sodium bicarbonate instead of silica sand. Other fine media used for abrasive blasting include glass beads, aluminum oxide, and crushed black walnut shells.
Fine media blasting is less hazardous to human health. It can also generate less heat, which is useful to avoid warping or melt risks.
Chemical Stripping
Chemical stripping is a strategy to remove finishes or patinas and debris from a machine’s surface. The most common type of chemical stripping is “paint stripping.”
Unlike abrasive blasting, chemical stripping involves the direct application of a liquid chemical. The chemical reacts with the paint or surface coating, forcing it to either peel away from the surface it costs, or dissolve entirely.
Most chemical stripping involves solvents, but occasionally caustic agents like turpentine are used.
Chemical stripping is good when you don’t want the surface to roughen, or you don’t want to risk damage from abrasive friction or heat. After applying the chemical and stripping the surface, it’s common to remove the remnants with a power washer.
Note: unlike abrasive blasting, chemical stripping is appropriate to use on wood and glass.
Machine Stripping
Machine stripping removes the surface layer, finish, or coating of a surface (typically a floor) using a specialized machine. Stripping machines are incredibly precise. They’re designed to only remove surface layers without affecting layers further down. While floor stripping machines are most common, new devices programmed to strip turbines are nearing market release.
Laser Ablation
Laser ablation can serve many of the same purposes as sandblasting, while increasing precision and personal safety. While chemical and machine stripping can only remove surface coatings, laser ablation can also remove rust and verdigris with the same degree of success as abrasive blasting.
It’s wise to choose laser ablation to clean or prepare the surfaces of machine parts and equipment made of rubber, polymers, resin or acrylic.
These materials cannot be cleaned or prepped via abrasive blasting. No matter what media is chosen, the abrasion would simply destroy them.
Laser ablation is also useful in spaces where environmental and anti-hazard safeguards, necessary to engage in abrasive blasting safely, cannot be implemented. Laser ablation devices are frequently used for rust removal by automotive manufacturers.
Precautions to Take When Sandblasting
When sandblasting or engaging in abrasive blasting with other media, it’s important to take precautions. To meet industry standards, professionals must read and apply OSHA’s specifications in full. These include:
- Utilize the least toxic viable blasting agent
- Wear all required PPE, including:
- A full-body protective suit
- NIOSH-approved respirator
- A cover or helmet enclosing head, neck, and shoulders
- Self-contained breathing device
- Gloves
- Boots
- Hearing protection (earmuffs, earplugs, etc.)
- Ventilate the blast area appropriately
- Implement isolation and containment controls
Precautions may also include implementing ISO 8501-8504 standards.
Sandblasting and Beyond: McLean Company Offers Industrial Expertise
Do you need industrial machinery cleaning, rust removal, or a fresh coat of paint? Or, maybe you need a complete upgrade of your commercial or industrial space?
At McLean Company, our experts know how to get your project done right. Call us at +1 (978) 774-4330, and we’ll work with you to deliver an excellent solution. Or, fill out our contact form below!