This article provides comprehensive information about abrasive blasting and sandblasting machinery. You will learn how these sandblasters are made and their materials of construction as well as applications, advantages, and drawbacks.
Read further to answer questions like:
Sandblasting machinery includes an array of systems and components designed to project blasting media onto surfaces, serving purposes like abrasion, cleaning, or surface modification. Various media types, such as sand, abrasives, and metal shot, are propelled via mechanisms like pressurized water, compressed air, or a blast wheel to perform these tasks efficiently.
This equipment features a wide variety of types, including:
To answer the question "how do sandblasters work?", it is crucial to understand the technology that powers blast equipment.
The technology used to energize or propel the blast media is a key factor in distinguishing different types of sandblasting equipment. Blast machines use either pneumatic air pressure or a blast wheel to project abrasives or media.
The pneumatic propulsion technologies used in blast machinery to clean, peen, or modify surfaces include:
Air or Dry Blast Equipment – Air abrasive blasting or dry blast equipment utilize compressed air to propel the blast media. Pneumatic or compressed air blast systems are generally categorized into two types: suction and direct pressure.
Suction or Siphon Blast Equipment – Suction blasters or blast cabinets employ the venturi siphon effect to such abrasive into a pressurized stream of fluid, air, or water.
Venturi devices use a constriction in a moving fluid stream to create a pressure differential or vacuum. This causes the blast media to be drawn into the air or water stream at the point of constriction.
Venturi devices are used across various industries. They are employed to create a vacuum for mechanical holding applications, while ejectors and eductors move fluids, powders, or solids in chemical processing industries.
Suction blast cabinets or portable siphon blasting pots are generally less expensive than pressure blast systems. Economy blasters often use suction mechanisms and do not require a pressure vessel, consuming only half the pressurized air compared to pressure blast cabinets. However, suction blasters need higher air pressure to maintain media flow.
Suction blast cabinets are less aggressive and require more time to achieve a clean impact. They are commonly used for short-run or light production, maintenance, and remote field applications.
The less aggressive nature of suction or siphon blasters extends the time needed to strip or clean parts. However, this reduced aggressiveness decreases the wear rate of parts within the blaster, leading to a longer lifespan and lower maintenance costs for the equipment.
Small handheld sandblasters may feature a cup above the blast gun to feed media into the gun’s venturi point by gravity. These gravity-fed blasters are a type of suction blaster, as they utilize the venturi siphon effect to operate.
Have you ever wondered why direct pressure blasters are more commonly used in industrial applications compared to suction blasters?
Direct Pressure or Pressure Blast Equipment – Pressure or direct pressure abrasive blast equipment makes use of a pressure vessel to energize the abrasive media. A pop-up or metering valve on the pressure vessel is opened to release pressurized fluid and blast media into a blast hose. The pressurized media travels through the blast hose to the direct pressure cabinet and blast gun.
Direct pressure cabinet blast machines expel blast media at significantly higher flow rates or speeds compared to suction blast equipment. The impact or kinetic energy (K) of the blast media is given by K = ½ mv², where m is the mass of the blast media and v is its velocity. Doubling the flow rate or velocity results in a fourfold increase in impact energy and blast cleaning efficiency.
Higher blast media speeds allow direct pressure systems to clean parts up to four times faster than suction blast machines. The pressure levels in direct pressure blast cabinets are more adjustable, enabling more precise control over cleaning and surface modification.
Direct pressure blast equipment can handle and propel heavy media such as steel shot, cut wire shot, and steel grit. Suction sandblasters often struggle with heavier media. Doubling the mass of the blast media doubles the impact energy. Heavier blast media (denser or larger) is more effective at cleaning and profiling than lighter, lower density, or smaller media.
A higher density or larger diameter, as well as a wider diameter nozzle or multiple nozzles, will allow for blasting with greater mass and higher energy impacts. Air compressors with greater flow capacity (CFM) are necessary to drive the increased mass through the blast system.
The higher speeds, ability to handle heavy steel media, more aggressive nature, and improved control of direct pressure sandblasting equipment make it more suitable for high-volume production and automated blasting applications. The increased blast media speeds also allow pressure sandblaster guns to operate effectively at greater stand-off distances from the part.
Pressure blasters use two to three times the volume (CFM) of compressed air compared to suction blast equipment.
Maintenance and safety of pressure vessels are critical concerns. The failure of a pressure vessel could pose risks to operators and damage the equipment. Blast system pressure vessels must be constructed in accordance with the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Codes.
Wet Abrasive Blast Equipment – Water can be used instead of air to propel the blast media. Wet abrasive blasting or water blasting can reduce dust generated during abrasive blasting by over 90%, which is crucial when stripping or cleaning parts containing heavy metals and hazardous materials.
An interesting aspect of water blast equipment is its ability to offer additional surface modification through water additives. Chemicals can be included to break down hard-to-remove films or grease, and anti-rust agents can be added to protect the parts until coatings are applied.
Although some suppliers refer to wet abrasive blasters as dustless blast equipment, no blasting system eliminates 100% of dust.
Water blasting can keep parts cooler compared to dry blasting, which helps reduce warping or distortion in thin sections. It is also advantageous for handling explosive dust, such as aluminum or titanium dust, as wet blasting suppresses static discharges and ignition risks.
Wet blasting can use up to 50% less blast media compared to dry blasting. It provides deep cleaning with less or no embedding of abrasive media. Wet blasting systems often include closed-loop media recyclers, oil separators, demisters, and filtration systems. The dust is converted into clean, disposable sludge waste.
In dry blasting, dust must be removed from parts using an air blow gun or washing, and dust collectors are required in factory settings.
Wet blasting combines washing and dedusting with the blasting process. Detergents can be added to the water to loosen deposits, dissolve oils or greases, and speed up the cleaning process.
Rust-inhibiting agents can be added to the water to prevent rusting of steel after blasting. If rust inhibitors are not used, the steel should be dried, oiled, or painted immediately after blasting to avoid rust formation.
Bacteria and microbes can grow in the blast water, forming slime films and releasing odors. Like other metalworking fluids and grinding coolants, blast water requires the addition of antimicrobial agents.
There are several types of water blasters and water abrasive blasters available.
Slurry Blasting Equipment – Dry blasting equipment can be retrofitted for wet blasting. Slurry blast systems, also known as air abrasive water blasters, use a water injection nozzle or water ring (halo) attached to an air blasting gun to introduce water into the blast media stream. They can suppress 50% to 85% of the dust generated.
The water ring or halo nozzles offer less dust control compared to water induction or injection nozzles.
Slurry blasters are highly versatile as they can dry blast, wet blast, rinse, and dry parts. However, a drawback is the cleanup of the muddy mess generated in field applications. Additionally, slurry blast equipment can be cumbersome for operators due to the heavy water hose attached.
The water blast technology I find most interesting is vapor abrasive blasting.
Wet Venturi Blasters – Wet venturi blasters function similarly to dry suction blasters, but instead of just air, they use a venturi vacuum generated by compressed air to draw in an abrasive water mixture. Some manufacturers refer to these systems as modified sandblasters. In venturi pot systems, air pressurizes the pot to maintain consistency during blasting. Although venturi blasters effectively suppress dust, they require high blast pressure to operate effectively, resulting in high consumption rates of water and blast media with limited flow control.
Vapor Abrasive Blasting Equipment – Vapor abrasive blasting, also known as wet blasting, liquid honing, vapor honing, dustless blasting, and slurry blasting, involves using water to remove contaminants from surfaces along with pressurized water and abrasive media. In this process, the abrasive media is mixed with water and pressurized in a pressure pot before being conveyed through the blast nozzle by compressed air, a method commonly referred to as slurry blasting.
Vapor blasting is gentler than dry blasting because the water acts as a cushion for the abrasive. It also dampens the process and contains the particles removed by the abrasive. Moreover, the water cushions the impact of the abrasive, dispersing it evenly over the surface in a feather-like pattern, which allows for a finer blast method.
Vapor sandblasters offer a wide operating pressure range and finer control over the wet abrasive blasting process compared to other wet blasters. These machines operate at very low pressures (30 psi) for paint stripping and can reach very high pressures for applications such as white metal blasting in corrosion control.
High-Pressure Water Blasters and Hydroblasters – When high-pressure water is used, blast media might not be necessary for certain applications. These systems, also known as aqua cleaners and hydraulic blasters, can clean surfaces using high-pressure water alone.
High-pressure water blasters operate at pressures of 6000 psi and higher – which is beyond the range of typical pressure washers. While they are effective for removing paint and light rust, they are not suitable for removing tightly adherent corrosion, rust, mineral scales, and other stubborn deposits.
I find it impressive that UHP water jetters can cut materials without the need for abrasive grits.
Ultrahigh pressure (UHP) hydroblasters or water jetters operate at pressures of 30,000 psi or more. These UHP systems are capable of removing heavy rust layers, thick scales, hard deposits, concrete, and coatings. They can even demolish and hydrocut materials like tanks, pipes, reactors, rebar, manways, and concrete. UHP hydroblasters can remove pressure vessel and reactor heads, even in explosive environments, without requiring purging.
I would guess that almost every foundry casting large steel or iron castings has a wheel blasting machine in their cleaning room. Read on to find out why!
Wheel Blast Equipment - Another major type of sandblasting or shot blasting equipment is based on centrifugal wheel blast technology. In this system, blast media is fed into the axis of a spinning turbine wheel impeller. A series of throwing blades or paddles on the blast wheel accelerate and fling the shot or abrasive media onto the parts.
Adjustments to the control cage around the spinning blades can direct the stream of media to control the blast pattern as well as the size and location of the "hot spot". The blast pattern can range from several inches to feet in width, depending on the wheel dimensions, wheel speed, and the distance between the wheel and part surfaces.
The hot spot refers to the region of the blasted surface that becomes hot to the touch. It indicates where the center of the blast flow is located and is the most aggressive portion of the blast media stream. In other words, the hot spot has the highest density of impacts per unit area. If the parts are not hot to the touch, the operator adjusts the blast pattern to move the hot spot onto the parts.
Wheel blasters are ideal for moving heavy blast media such as steel shot, stainless steel shot, metal grit, cut wire shot, and cast shot. Aluminum oxide and other angular abrasive media are not typically used in wheel blasters. Round steel shot is particularly effective for cleaning castings, descaling forgings, and shot peening structural components.
The shape and hardness properties of the media, or whether any media is used at all, are additional parameters controlling the blasting process. Blast machines are also defined by the blast media type employed:
Abrasive Blasters - Abrasive blasters are conventional sandblasters designed to impact hard, angular grits against a surface. Blasting abrasive compositions include aluminum oxide, silicon carbide, coal slag, garnet, mineral sands, ilmenite, olivine, pumice, staurolite, crushed glass, abrasive sponge media, micro-abrasives, and copper slag. The blast nozzles, blast hoses, and surfaces in abrasive blasters need greater wear resistance and require more frequent maintenance and replacement.
Non-aggressive Media Blasters – Non-abrasive media includes walnut shells, soda (sodium bicarbonate or baking soda), plastic grit, corn cobs, and starch. Equipment designed for blasting non-abrasive media does not require components with the extreme wear resistance of abrasive blasters. Blast nozzles, blast hoses, and internal surfaces should last longer before replacement is required.
What I find very intriguing about shot peening equipment is its ability to alter the strength of parts by orders of magnitude, increasing it by up to 5 times.
Shot Peening Machines – Peening impacts a surface with spherical steel, stainless steel, glass beads, or ceramic ball media to impart compressive residual surface stresses on a part.
Most shot peeners or shot peening machines use centrifugal wheels or pressure blasting to project shot peening media effectively.
Ice Blasters – Dry ice blasters and water ice blasters clean surfaces using frozen media such as dry ice (solid carbon dioxide) or water ice (H2O). Both dry ice and water ice are non-aggressive media types.
Ice blasting equipment must be designed to handle the cold media and the resulting condensation on lines, cabinets, pots, and vessels. The materials used in construction must avoid plastics or metals that become brittle at lower temperatures.
Dry ice is gentler and softer compared to plastic media. It can be used in two forms: pellets and shaved or snow-like flakes. NASA engineers have employed dry ice, or carbon dioxide snow-like crystals, to remove particle contaminants and molecules from the surface of a space telescope mirror without causing any scratches or profile changes.
Dry ice and water ice blasters offer cleanup benefits over conventional blasters. Water ice grits evaporate after blasting, while dry ice sublimates into gaseous carbon dioxide. The sublimation process of dry ice absorbs heat from the part's surface, which can assist in paint removal and cleaning.
Sandblasting equipment can consist of complete blasting machines or abrasive blast packages preconfigured with the required components. Sandblasting equipment can be modular. You can configure a sandblasting system specifically for your application by selecting various parts from a supplier‘s catalog. Parts include blast guns, wear-resistant nozzles, , valves, deadman handles, blast cabinets, blast rooms, and blast hoses.
Sandblasting equipment can vary significantly in size and configuration based on the specific application, the size of the parts being blasted, their intended function, and the setting in which they are used, whether in a lab, shop, production line, or field/remote sites.
Benchtop Micro Blasters and Pencil Blasters – Microabrasive blasters, also known as micro blasters, feature small nozzles with diameters ranging from 0.018 to 0.125 inches. Some of these nozzles are crafted from sapphire or single crystal alumina. Media sizes used in these systems range from 10 to 350 microns. Microblast cabinets can be either benchtop or floor-mounted, and handheld pencil blasters, which often have a small gravity-fed media cup, are a type of micro blaster.
Micro-abrasive blasting systems are commonly used for cleaning, stripping, and etching small parts and detailed work in applications such as dental, jewelry, and electronics (PCBs). They are also used for deburring stainless cannulas, microtubes, and hypodermic needles.
Manual Blast Cabinets or Cabinet Blasters – Manual blast cabinets are equipped with two holes, each fitted with rubber blasting gloves, which allow the operator to handle parts and position the blast nozzle at the correct stand-off distance. This setup enables the operator to create a hot spot and move it across the surface to clean or etch it effectively.
The cabinets feature a window and internal lighting, enabling the operator to view the parts and the blast gun without direct exposure to the blast. Some blast cabinets also use air blasts across the window to maintain visibility by preventing dust accumulation.
Used blast media collects in the cabinet's steel or fiberglass grate and falls into a hopper. From there, it is transported to a separator where the abrasive is recovered. In more budget-friendly blast cabinets, this separation step might be bypassed, and the used media is recycled directly. This can lead to a buildup of dust and fragmented media, reducing efficiency and potentially harming filters.
Ideally, all media and dust should be contained within the cabinet and its filtration system. Over time, however, blast cabinets can develop leaks as seals degrade. A frequent issue is the leakage around doors, often because the doors are not securely clamped around the entire edge.
A notable player in the industry, Titan Abrasive Systems, has introduced an innovative, patent-pending technology designed to eliminate issues with blast cabinet door leaks or warping. Their doors feature a dual-panel construction with robust steel channels and an enhanced locking mechanism. This system ensures a tight seal along the entire edge of the door, with a knife-edge design that guarantees a secure closure each time.
Blast cabinets can be designed with various door configurations, including front, top, and side openings. Some models come with multiple doors, enabling simultaneous loading and unloading—one door for introducing dirty parts and another for removing cleaned items. Depending on the design, doors may swing open, lift upward, or slide horizontally.
Pass-through blast cabinets are specifically designed for processing glass sheets or metal plates. These systems feature a narrow opening equipped with specialized brush or rubber flap seals to minimize abrasive leakage. The sheet or part is fed through the gap and moved along using rollers inside the cabinet.
Manual blast cabinets are well-suited for environments such as machine shops, garages, auto body shops, light manufacturing, short production runs, finishing touches on production parts, prototyping, and custom projects.
Industrial-grade blasting machines are engineered with enhanced durability and quality to withstand the rigorous demands of production environments. These systems are specifically designed to manage higher volumes of parts or accommodate larger components such as castings, forgings, extrusions, or structural shapes.
These machines can be equipped with several blast guns, each strategically positioned to target specific sections of the part. For instance, a system with 12 guns will experience significantly higher rates of compressed air and media consumption.
Automated vs. Manual – Production sandblasting systems can either be operated manually or through automation. For parts with significant variation in size, shape, and production volume, a manual loading or unloading system might suffice. However, automation is recommended for larger production runs or where maintaining consistent quality is crucial.
Sandblasting systems can be categorized as semi-automatic, fully automatic, or turnkey. In a semi-automatic setup, operators may manually load or secure parts onto a table or hanger. Once the blast chamber door is closed, the parts undergo rotation and blasting according to preset or programmed settings. After the initial cycle, the operator may need to adjust or reposition the parts to ensure thorough cleaning of all surfaces. In contrast, turnkey or fully automated systems handle part loading, movement, and blasting parameters entirely through automation.
Automation can also manage part handling and gun manipulation. It provides precise control over gun distance and movement speed across the part surfaces, leading to more uniform cleaning and preparation with minimal missed areas. Although automation involves higher initial costs, it can be balanced by lower labor costs, increased throughput, fewer rejects and rework, and enhanced quality.
Fixed Station and Robotic Blasters – Fixed station and robotic blasting setups feature blast guns mounted on robotic arms. Parts are either manually or automatically loaded into the machine, and then the robotic nozzle performs the blasting by scanning and treating specific surface areas.
Robotic blasting systems are prevalent in industries like aerospace and automotive, where they handle abrasive blasting and shot peening for intricate components such as turbine blades, pump impellers, engine parts, and valve assemblies.
Batch and Pass-through Blast Chambers – Batch systems, such as tumble and table blasters, process multiple parts at once within the blast chamber. Pass-through systems allow parts to move through an opening equipped with brush or rubber seals to control abrasive leakage.
Inline and Continuous Blasting Systems – For high-volume and ongoing production, blasting equipment can be integrated into production lines. This setup is used for continuously blasting alloy strips, plates, or sheets in metal mills, including descaling and cleaning steel stock, structural steel, and pipes. Inline systems have abrasive blasting guns or wheels positioned above and below the moving materials, ensuring continuous cleaning as the material progresses along the production line.
Large-scale inline abrasive blasting systems are designed for use in production lines, where materials or parts are exposed to blasting equipment. These systems often feature automatic or remotely controlled guns.
In continuous or semicontinuous processing of metal sheets or other stock materials, blasting nozzles or wheels are mounted both above and below the moving material, allowing for uninterrupted cleaning as it travels along the mill line.
The Eco Pickled Surface (EPS) method by TMW utilizes steel grit blasting as an alternative to traditional acid pickling. This EPS process yields sheets and strips with a more uniform surface texture, enhanced coating adhesion, and superior weldability.
Blast Rooms – Blast rooms are designed for cleaning parts that are too large for blast cabinets, table blasters, or hanger blasters. These spacious areas can accommodate operators and, in some cases, even large vehicles or material handling equipment.
In a blast room, used blast media falls through the floor grating and is collected for further processing. The reclaimed media is then transported to a separator or reclaimer using mechanical or pneumatic methods.
Operators in blast rooms wear comprehensive protective gear, including a sandblasting suit, hood, gloves, respirators or air supply systems, and hearing protection. The blasting is carried out using a portable blasting unit or a stationary machine integrated into the room.
Blast Booth Lifts – Blast booth lifts offer a solution to the need for personal protective equipment (PPE) in blast rooms. These lifts feature an enclosed space with windows where the operator is protected. The operator can control the blasting gun and maneuver the entire booth both vertically and horizontally within the blast room. These lifts are particularly effective for cleaning tall tanks, structures, ships, and vehicles with impact blasting.
Media Separators and Dust Collectors – In many production blast rooms and blasting setups, media separators are used to reclaim and recover used blast media. The cleaned media is then returned to the blast media pot or container. Dust and fragmented media are directed to a dust collector and filtration system, which captures the dust for proper disposal.
Tumble Blasters – Tumble blasters feature a rotating basket or a continuous rubber belt that tumbles parts during the blasting process. Parts should be compatible with the tumbling action, as delicate components with thin fins or intricate shapes may suffer damage or become tangled. For such parts, alternatives like hanger blasters or wire mesh belt blasters are recommended.
To ensure the longevity of the tumble belt or basket, it should be adequately loaded. Avoid overloading as it may prevent proper media contact with the parts and can also lead to damage of the tumble belts or baskets.
Table Blasters – Table blasting systems are designed to clean large, heavy castings and forgings. These systems use a rotary table positioned within a blast chamber. Once the chamber doors are closed, the table rotates, allowing the blast media to clean the part's surface while it spins.
Since the bottom of the part remains in contact with the table, it is not exposed to the blast media. To clean the underside of the part, it must be manually flipped over.
Hanger Blast Systems – In hanger blasting systems, parts are suspended from hooks, allowing them to be fully exposed to the blast media stream. This method ensures that nearly every surface of the part is thoroughly cleaned.
Wire Mesh Belt Blasters – These systems use a durable manganese steel wire mesh belt to transport parts through a stream of blast media. The belt should always carry parts; if only a few parts are being treated, dummy or scrap parts should be placed on the belt to minimize wear.
Monorail Blast System – Monorail blasting systems feature an overhead rail that supports parts as they are transported into the blast chamber. Parts enter through doors or a pass-through opening, undergo blasting, and then exit through the opposite end where they can be removed from the monorail.
Roller Conveyor Blast System – Roller conveyor systems are used for cleaning larger metal stock like billets, thick plates, and structural components such as I-beams. The rollers facilitate the movement of these heavy materials through the blasting area.
Portable Blasters and Blast Pots – Portable sandblasting equipment is designed for use on-site to handle large surfaces such as ships, storage tanks, trucks, railroad cars, bridges, buildings, and agricultural machinery. These systems typically include portable blast pots, air hoses, blast hoses, blast guns, and air compressors, allowing them to be easily transported and used in various field locations.
Walk-Behind and Vertical Blasters – Walk-behind blasters are equipped with a blast wheel and are used for cleaning concrete floors, often with an integrated vacuum system to collect debris and dust. Vertical blasters, on the other hand, are specifically engineered for cleaning vertical surfaces like concrete and brick walls within industrial environments.
Blasting Trailers and Blasting Trucks – Mobile sandblasting units come in the form of trailers or trucks that can be transported to remote job sites. Blasting trailers are towed to the location, while larger blasting trucks are driven directly to the work area. These mobile units often feature engine-driven compressors to ensure a steady supply of compressed air.
Internal and Pipeline Blasters – For cleaning and rust removal inside pipes, specialized blasting tools or lances are employed. These tools are designed with collars to center the blast nozzle and use tungsten carbide deflecting tips to direct the abrasive stream against the inner pipe walls.
Spin blast units equipped with rotating heads and multiple nozzles angled towards the pipe surface are also used to achieve comprehensive cleaning.
Sandblasting equipment is assembled from a diverse range of components including cabinets, pressure vessels, hoses, guns, and nozzles. Each of these parts is produced using various manufacturing techniques such as sheet metal fabrication, casting, welding, mechanical fastening, machining, and other specialized methods.
Blast cabinets and blast rooms generally begin as constructed metal enclosures. These are typically created by cutting, bending, and shaping steel sheets, plates, and structural steel to form the necessary sides, legs, and doors to complete the box structure.
By incorporating additional elements such as blast guns, viewing windows, glove ports, doors, turntables, grating or screens, gun or part holders, pneumatic valves, foot pedals, lighting, hoses, and reclamation systems, the basic enclosure evolves into a robust industrial tool: a blast cabinet or blast room.
Blast cabinets can be assembled using welding or mechanical fastening methods. Fastening methods facilitate easier removal for maintenance, cleaning, and part replacement. On the other hand, welded cabinets offer a more airtight seal, reducing leakage of media and dust into the workspace, though replacing worn components can be challenging.
Over time, the abrasive blast stream causes wear to the bottom and sides of the cabinet. The seals and windows also degrade with use and will eventually need replacement.
What materials are used in the construction of sandblasters?
Dry or air blasting cabinets and rooms are typically constructed from steel, which may be coated with powder, zinc galvanization, or industrial paint. For wet blasting applications, materials like stainless steel are preferred due to their resistance to corrosion.
In specific dry blasting scenarios, such as those involving surgical instruments or medical implants, stainless steel might be used to prevent iron contamination of surfaces.
When blasting stainless steel parts, stainless steel shot or non-metallic abrasives are commonly used. Steel shot or steel parts can transfer metal particles to the stainless surface, potentially compromising its passivation layer and leading to rust.
To minimize wear on blast machines, wear-resistant steel liners or wear plates are installed within blast chambers. These liners are made from alloys known for their durability, such as manganese steels like Manganal and nickel-chromium white cast irons like Ni-Hard alloys.
What Components and Consumables Are Found in a Sandblaster?
Sandblasting equipment often suffers from wear and tear due to the harsh nature of the blast media. Components of the blaster are considered consumables and gradually degrade as abrasive or media continually flows through or impacts these parts.
Blast media itself is also subject to consumption. Some abrasives like steel shot, ceramics, and aluminum oxide can be recycled multiple times within the blaster, whereas materials such as soda, dry ice, sand, and coal slag are typically used only once.
Components in abrasive blasters, wheel blasters, and shot peening machines must be regularly checked for wear and tear. Changes in the nozzle's inner diameter or alterations in the geometry of throwing blades can significantly affect the efficiency of the blasting operation.
Sandblaster parts are:
Blast nozzles are made of extremely wear-resistant materials are:
Among the most durable materials for sandblasting nozzles are boron carbide, alumina, pure tungsten carbide (WC), and silicon carbide ceramics.
Depending on the type of blast media used, nozzles made from cemented tungsten carbide and SiAlON can last 10 to 20 times longer than those made from ceramic or alumina. Boron carbide stands out as the hardest and most wear-resistant option among these materials.
Although boron carbide generally costs about three times more than cemented tungsten carbide, it can last anywhere from 3 to 25 times longer than tungsten carbide or SiAlON nozzles. However, boron carbide lacks the toughness and impact resistance that cemented tungsten carbide offers. Binderless tungsten carbide (WC) nozzles have twice the lifespan of boron carbide nozzles.
Steel nozzles are suitable for use with air blow guns, washout guns, and for blasting exceptionally soft media like soda, dry ice, walnut shells, and plastic grit. They are less likely to break if dropped. Inexpensive sandblasters intended for home or DIY use often feature steel nozzles.
For wear resistance alone, boron carbide and binderless tungsten carbide nozzles can last up to seven times longer than cemented tungsten carbide. However, boron carbide or silicon nitride nozzles are more prone to cracking if they strike a part, grate, or cabinet wall compared to cemented tungsten carbide nozzles.
The service life of nozzles can vary based on the type of media being used. Nozzles tend to wear out more quickly when blasting sharper, angular steel grit compared to spherical cast shot. Similarly, materials like aluminum oxide and silicon carbide will cause faster nozzle wear than garnet or coal slag. In contrast, nozzles used for blasting softer media such as plastic, soda, corn cobs, or walnut shells can last much longer, potentially even indefinitely.
Beyond consumables and wear components, there are various sandblasting accessories and ancillary equipment designed to enhance the blasting process:
Both sandblasting and shot peening operations necessitate the use of personal protective equipment (PPE) for operators to ensure safety:
Sandblasting equipment can alter the surfaces of parts or structures in numerous ways, depending on the type of media used and the blasting parameters. Softer media applied at lower pressures can delicately strip coatings, while high-pressure projections of extremely hard abrasives can aggressively etch, texture, or carve surfaces. For instance:
Sandblasting equipment offers various end-use and surface modification functions that can enhance your production processes:
Cleaning / Stripping – Mechanical cleaning through impact or abrasive blasting is one of the most common applications for sandblasting equipment. It is highly efficient at cleaning surfaces and removing substances such as rust, oxide scale, mineral deposits, corrosion, grease, dirt, coatings, sealants, carbon deposits, and varnish.
Unlike wire brush wheels, abrasive belts, and abrasive discs, which tend to clog quickly when dealing with paints, coatings, and contaminants, abrasive blasting transforms these materials into dust, which is then managed by dust collectors, industrial vacuums, and separators.
The aggressiveness of the cleaning process can be adjusted by selecting different blast media, pressures, flow rates, and types of blasting machines. For example, abrasive blasters can delicately remove graffiti, paints, and coatings without affecting the underlying material.
Alternatively, an abrasive blaster can aggressively clean a steel surface to achieve a NACE/SSPC "white metal" cleanliness grade by thoroughly removing all rust, scale, or other contaminants.
Blending, Smoothing, and Surface Finishing – Sandblasting is effective for eliminating marks and machining lines left from grinding and other processes. Spherical media, such as steel shot and glass beads, are particularly adept at blending and enhancing surface finishes.
The rounded edges of these media gently flatten high spots on the surface, resulting in a brighter, matte finish. In contrast, using sharp, angular abrasives achieves a duller, satin finish, which offers excellent bonding properties.
Refining Surface Finish and Enhancing Fatigue Strength – Improving the surface finish or reducing the surface profile can significantly boost fretting fatigue strength, potentially increasing it by 20% to 200%. To achieve this, a larger diameter or heavier cast shot can be used initially to introduce a deep residual stress layer. Subsequently, the surface is peened with smaller spheres or microbeads to refine the finish.
If the part has a rough surface finish, such as that found in as-cast or as-forged components, peening can modestly improve the finish. However, if the part has been ground or machined to a smooth or low Ra finish, shot peening may result in a rougher surface profile.
Deflashing – Flash or excess material often forms at the seam where the two halves of a mold meet during plastic molding, rubber molding, sand casting, or die casting. This flash on molded metal, plastic, or rubber parts needs to be removed, and the remaining parting line blended.
Plastic and rubber parts are sometimes cryogenically frozen with liquid nitrogen at -300°F (-184°C). This process makes the plastic and rubber flash brittle, allowing it to be easily removed by blasting.
Deburring – Metal parts often develop slivers, attached swarf, and sharp protrusions during various operations such as sawing, machining, drilling, cutting, shearing, and grinding. These imperfections can pose safety risks by cutting workers or customers, creating handling hazards. Sandblasting is an efficient solution for removing these burrs, including those in hard-to-reach recesses where conventional deburring tools might struggle.
Burrs and slivers can pose significant safety risks, potentially causing injuries to hands and creating handling difficulties. Sandblasting offers a quick method to eliminate these issues, effectively cleaning edges and recesses that mechanical tools might not be able to reach.
Demolition / Cutting – Ultra-high pressure water jets or water blasters are utilized for demolishing concrete, cutting rebar, and opening pressure vessels for maintenance and inspections. Another related technique, abrasive water jet cutting, is capable of creating complex 2D patterns in virtually any type of sheet or plate material without the thermal damage associated with plasma or flame cutting.
Drilling / Carving – Micro abrasive blasters are adept at drilling tiny holes in printed circuit boards. They can also carve intricate designs into materials like glass, wood, and stone, allowing for the creation of both 2D patterns and 3D shapes.
Patterning / Marking – Abrasive blasting is employed to etch designs, part numbers, and text onto surfaces. This is achieved using various masking materials such as tapes, films, and compounds, which protect the areas not intended for blasting. These masking materials are generally soft or flexible to ensure that the protected areas remain unaffected.
Micro-abrasive blasters are equipped with very fine blast patterns, enabling precise tasks such as patterning, deburring, cleaning, marking, and even drilling or cutting without the need for masking in certain situations. They are particularly effective for cutting slots and holes in semiconductor wafers or milling channels into ring bearings.
Surface engineering involves altering the surface properties of a part to impart specific characteristics that either enable or improve its performance for particular applications.
Peening involves bombarding the surface with spherical media such as steel, stainless steel, glass, or ceramic to induce strain hardening and create compressive residual stresses on the part. Commonly used media includes cast steel shot with a Rockwell C hardness ranging from 40 to 55.
Shot peening can enhance the fatigue strength of components by as much as 30% to 500% due to the induced compressive residual stress. This improvement in fatigue strength and resistance to stress-corrosion cracking is crucial for components like fasteners, gears, axles, dies, molds, shafts, springs, aircraft landing gear, and other rotating and structural parts.
Etching / Surface Profiling – This process involves creating specific surface textures, roughness, and profiles. A roughened surface improves the adhesion of coatings, paints, and adhesives compared to a smooth one. Abrasive blasting creates an anchor profile with undercuts and increased surface area, which enhances the bonding of coatings and adhesives.
A sandblasted surface on stainless steel handrails also improves grip, benefiting users. Additionally, etching can modify the frictional properties of a surface, which is advantageous in mechanical power transmission applications.
Surface Preparation – This process involves both cleaning the surface and creating an anchor profile or modifying surface roughness. Proper surface preparation is essential before applying coatings, paints, galvanizing, oiling, welding, brazing, sealing, soldering, adhesive bonding, or rubber-to-metal bonding.
For optimal adhesion, surfaces must be free from grease, oil, dust, and dirt. Contaminants can interfere with bonding by acting as a barrier or a release agent. Effective cleaning is crucial to ensure proper chemical bonding and adhesion.
It is also important to remove rust and corrosion, especially when applying protective coatings that must meet the standards set by the National Association of Corrosion Engineers (NACE) and the Society of Protective Coatings (SSPC). Abrasive blasting is commonly used for rust and corrosion removal for three main reasons:
Standards such as those from NACE, SSPC, and ISO 8501 offer visual guidelines for evaluating surface cleanliness and the extent of rust, mill scale, and other contaminants. NACE and SSPC have collaborated on a joint standard specifically for Industrial Blast Cleaning.
These standards range from the lowest cleanliness grade, known as "Brush Off," to the highest cleanliness grade, "White Metal."
Is your surface truly "profiled"?
Even if a surface appears clean, it may not be adequately "profiled" for optimal adhesion. Smooth surfaces offer few anchor points for paints and coatings. By contrast, a surface that has been roughened through blasting provides better mechanical interlocking for coatings, ensuring a more secure bond.
Should you use the roughest and sharpest blast media for surface preparation?
Not necessarily. While a rough surface can enhance bonding, overly aggressive blasting might lead to problems. Excessive roughness can cause thinner coatings to leave pinholes or fail to cover the surface adequately, leading to potential corrosion issues. For improved coating performance, some of the high peaks on the surface profile can be reduced through more controlled blasting techniques.
Coarse grit blasting is effective for applications requiring strong bonding, such as thermal spray deposits, thick coatings, and polymeric linings. However, for thinner coatings and paints, a less aggressive profile with fewer sharp peaks is preferable. This can be achieved using spherical media like round steel shot or glass beads, which create a more uniform surface profile.
Aerospace – Plastic media blasting is employed to remove old paint from aluminum aircraft skins while preserving the underlying aluminum metal. This process is crucial for maintaining the integrity of the aircraft structure. Additionally, blasting plays a role in the refurbishment of jet engine parts and in non-destructive testing (NDT) for inspecting aircraft structural components.
Additive Manufacturing / 3D Printing – In additive manufacturing, abrasive blasting is used to remove support material from 3D-printed parts. It also helps in smoothing surfaces and blending striation lines that may appear during the 3D printing process, enhancing the final finish of the printed object.
Agriculture – Sandblasting equipment is utilized to clean and remove rust, as well as dislodge soil from farming machinery such as tillers, tractors, cultivators, harvesting machines, reapers, pickers, and pesticide sprayers.
Automotive OEM – In automotive manufacturing, abrasive blasting is essential for etching, cleaning, and preparing automotive parts before processes like welding, adhesive bonding, and painting. Additionally, many castings, forgings, and machine components undergo shot peening to enhance material properties and extend their lifespan.
Automotive Aftermarket – Sandblasters are crucial tools in auto body shops and repair garages. They are used for rust removal, body and engine repairs, and the restoration of antique vehicles.
Adhesive Bonding / Sealant Application – Surface cleaning and anchor profile generation through sandblasting increase the bond strength of adhesives and sealants, ensuring a more secure application.
Architectural / Building & Construction – Sandblasting is employed to remove paint and rust from steel, concrete, and wood surfaces in buildings. Soda blasting is particularly effective for architectural cleaning tasks such as graffiti removal, paint stripping, and cleaning and deodorizing areas affected by fire, smoke, and mold.
Vertical sandblasters are designed for cleaning brick, stone, and concrete walls. Walk-behind sandblasters, which are wheeled across surfaces, are used to clean concrete floors before recoating. Both vertical and walk-behind blasters often feature integral vacuum systems to collect blast media and dust.
Chemical Plants / Refineries – In chemical plants and refineries, where corrosion is a persistent issue due to exposure to acids, salts, and other corrosive substances, sandblasting is essential for removing corrosion from tanks, pipes, valves, and pumps.
Corrosion under insulation (CUI) is a common challenge in these facilities, particularly with insulated piping systems. Sandblasting is used to remove corrosion from beneath the insulation, after which a new protective coating is applied before reinsulating the pipes.
Coatings on industrial flooring and concrete walls in chemical plants often deteriorate or wear out over time. Walk-behind and vertical blasters are employed to strip away old coatings and prepare the surfaces for the application of new industrial coatings.
Coating and Paint Application – Sandblasting plays a crucial role in surface preparation by cleaning and creating an anchor profile, which enhances the bond strength of paints and protective coatings. It is indispensable for preparing surfaces to accept new coatings and for ensuring proper adhesion.
When recoating or repainting surfaces, sandblasting is necessary to strip away old, damaged coatings and rust before applying a new layer.
Corrosion Control Industry – In the corrosion control industry, sandblasting is used to strip away damaged coatings, paint layers, rust, corrosion, grease, dirt, adhesives, and sealants in preparation for recoating or repair. Non-destructive testing (NDT) inspections or corrosion assessments also require precleaning of surfaces.
Surface preparation standards and cleanliness grades established by organizations such as the International Organization for Standardization (ISO), National Association of Corrosion Engineers (NACE), Society of Protective Coatings (SSPC), and American Society for Testing and Materials (ASTM) are crucial for properly preparing surfaces before applying protective coatings.
NACE estimates the annual cost of corrosion to be $2.5 trillion!
Sandblasting equipment is one of the most powerful tools in corrosion engineers' arsenal to combat the ongoing battle against rust and corrosion.
Bridge & Highway Maintenance – Weathering, erosion, and corrosion gradually deteriorate structures. Without proper maintenance, bridges and other infrastructure can suffer significant damage, potentially leading to catastrophic failures.
Blasting is essential for maintaining concrete and steel structural members on bridges, overpasses, and highways. It removes old protective coatings, facilitates inspection, and prepares surfaces for the renewal or reapplication of protective coatings.
Electronics / Electrical – Micro abrasive blasters are invaluable tools for electronics repair. They can precisely remove solder where reflow desoldering is impractical and strip conformal coatings that cannot be removed with heat or chemicals. Micro-blasters are also used to drill holes or vias in printed circuit boards (PCBs) and clean surfaces for soldering or brazing. A clean metal surface is more readily wetted by molten solder or braze.
Foundries and Forges – In foundries and forges, abrasive blasters like centrifugal wheel blasters and pressure blasting equipment are vital for cleaning operations. After shakeout, castings are blasted with metal shot or grit to remove residual mold sand and ceramic investment material, followed by cleaning to remove any surface oxide scale. Forged parts are also blasted to eliminate die lubricant and descaled oxide layers.
Glass Fabricators – Glass panes or windows, glass bowls, glass cups, and other decorative glass objects can be frosted or patterned using stencils or masks. Microblasting is another method used to etch or engrave text and graphics onto a glass object.
Sandcarving uses abrasives to deeply etch away glass and create 3D relief patterns or images. Glassware is usually blasted with 180 grit silicon carbide.
Jewelry / Fossils - Micro blasters with soft grits can clean delicate surfaces, such as removing encrustations on fossils. Micro-blasting with abrasives that are softer than gemstones can clean jewelry without damaging precious stones.
Machine Shops / Manufacturing – Most machine shops, fabricators, and manufacturers have at least one blast cabinet for cleaning, degreasing, deburring, and surface preparation of machined or fabricated parts. Dies, molds, drills, end mills, saw blades, and other tools are also blasted to remove burrs and embedded debris stuck on cutting edges or between teeth. Shot peening can enhance the fatigue strength and life of machined or ground shafts, tools, and structural parts.
Marine – Sandblasting is crucial in boat and shipbuilding and maintenance. Decks, hulls, and interior surfaces need protection from the corrosive effects of ocean salt sprays and mists.
Fouling on the bottoms of ship hulls increases drag, resulting in higher fuel costs for major shipping companies. Ship hull bottoms are cleaned by blasting to remove algae, barnacles, and marine life before recoating with low drag, ablative bottom coatings.
Medical / Dental – Cleaning, coating preparation, etching, and polishing of medical devices and dental restorations. For instance, the investment or mold material on cast crowns or bridges can be carefully removed using a small benchtop sandblaster or micro-blaster. Hip, shoulder, dental, and other bone and joint implants are blast cleaned to comply with strict FDA cleanliness standards.
Mining & Gas & Oil Fields – Various mining, gas, and oil field equipment needs rust removal and protective coating. Sour gas contains hydrogen sulfide, a toxic and highly corrosive chemical.
Monuments / Tombstones – Portable sandblasters can etch or clean stone monuments and tombstones in remote locations such as national parks and graveyards.
Nondestructive Testing (NDT) – Coatings, rust, corrosion, grease, and other surface contaminants must be removed before structural components can be inspected for surface and subsurface cracks and defects. Ultrasonic, eddy current, penetrant testing, magnetic particle, and visual testing methods require a clean surface for accurate evaluations.
Plastic / Rubber Molding – Deflashing molded parts and cleaning excess resin from molds or forms. Dry ice blasting is commonly used for cleaning plastic and rubber molds. Rubber becomes brittle at low temperatures and can be abraded away, while cryogenic blasting is used to deflash rubber and plastic parts that have been cooled to cryogenic temperatures.
Rail / Mass Transit – Railcars, tanker cars, railcar wheels, and track mechanisms are cleaned to inspect for cracks and corrosion and to prepare for protective coating applications. Blast rooms or portable blast pots are typically used for cleaning and surface preparation of rolling stock.
Remanufacturing – Used or damaged engines, blocks, heads, brakes, and transmissions are repaired or refurbished by remanufacturers. Sandblasting equipment cleans these components to remove rust, grease, gaskets, and coatings from surfaces. Mating surfaces are ground to eliminate warpage, and cylinders are reground or relined. The remanufactured engine is then reassembled and either returned to service or resold.
Steel / Metal Mills – Sandblasting equipment is utilized in primary and secondary metal and steel mills for descaling and cleaning metal sheet, plate, strip, bar stock, rod stock, and other shapes. Scale or metal oxide formed during hot rolling, extrusion, drawing, or other thermomechanical processing is removed with abrasive blasting media. The blast nozzles are positioned over the moving metal or steel plates, continuously cleaning the metal stock as it progresses along the production line.
Thermal Spray Coating – Creating an anchoring surface profile with abrasive blasting is essential for achieving strong bond strength in thermal spray coatings on jet engine blades and other critical components. Thermal spray coatings will delaminate from smooth, unblasted surfaces.
Welding, Brazing & Soldering – Abrasive blasting is used before welding, brazing, and soldering to clean surfaces and ensure solid joint formation. After joining, additional blasting removes slag, rosins, oxide patinas, and weld spatter before applying protective coatings.
Woodworking / Cabinetry – Sandblasting removes paint or wood sap from wooden cabinets, furniture, and trim before painting. It is also used for wood carving and sign etching.
Sand Blasting Advantages
Certain materials such as lead-based paints and heavy metals generate harmful or toxic dust when blasted. In these applications, specialized vacuum blasting systems or systems with high MERV filtration is required to prevent the release of harmful materials.
Operators should use a breathing air supply filter when blasting hazardous materials any material generating fine, respirable dust in a field or open factory environment.
Proper collection, handling, and disposal of the media are required as well. Wet or water blasting systems reduce the dust problem.
Answering these questions will assist you in choosing the appropriate blasting system for your surface treatment needs.
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