What Is Abrasive Blasting?Updated: August 18, 2023
Do your manufacturing processes involve working with metals like steel or aluminum? Your workpiece surfaces may contain dirt, chemicals or imperfections that can minimize the results when performing various finishing techniques. Abrasive media blasting provides a fast, effective solution for removing these materials and preparing the substrate for the next steps.
A Breakdown of Abrasive Blasting
Abrasive blasting is a general term to describe finishing processes involving directing a high-pressure abrasive material stream to a workpiece surface. You can use this process to achieve various surface finishing purposes, including roughening or smoothing the surface, removing previous coatings or contaminants and altering the surface shape.
There are a variety of abrasive blasting applications, and each requires a different blasting media. Finishing Systems has assembled this abrasive blasting media guide to help you select the most appropriate material for your specific finishing processes.
One note: the terms “sandblasting” and “abrasive blasting” are often used interchangeably. A conventional “dry” sandblasting process that uses traditional sand is not recommended for most applications. Blasting with sand generally requires twice the amount of material, making it cost-prohibitive for many companies.
Sand also contains significant levels of silica, which, when broken down and inhaled by operators, can result in severe respiratory disorders. Consequently, you can typically conduct common sandblasting projects by utilizing alternative types of abrasive material.
What Are the Benefits of Abrasive Blasting?
Abrasive media blasting offers many benefits for manufacturing and surface finishing:
- Promotes adhesion: By powering away dirt, grease, corrosion and other substances, abrasive blasting leaves a clean, contaminant-free surface. You’ll find that paints, powder coatings and other materials adhere to the underlying metal more easily.
- Enables customized finishes: Abrasive blasting puts you in control of your surface preparation results. Choose the media type and size that allows you to create the level of roughness or smoothness that meets your project’s specifications.
- Delivers efficient results: This process allows the media-filled liquid to reach the smallest nooks and crannies on the workpiece’s surface. You’ll experience a thorough cleaning and material removal result that avoids wasting media and saves time and money.
- Minimizes the damage risk: Using chemical stripping and other harsh surface preparation techniques could permanently damage or deform the substrate. Abrasive blasting significantly reduces the likelihood of damage, assuming you implement each process step correctly.
- Protects the environment: Abrasive blasting utilizes media such as steel shot, corn cobs, aluminum oxide and walnut shells instead of toxic chemicals to clean surfaces. You achieve high-quality results without releasing harmful substances into the atmosphere or emitting greenhouse gases.
The Abrasive Blasting Process
Abrasive blasting uses compressed air to accelerate a grit of small particles to clean objects and surfaces. This process can create a significant amount of dust, and you must isolate the process from the operator to minimize health risks from the abrasive blast dust. Check out this step-by-step guide to the abrasive blasting process:
- Choose the proper blasting equipment and material.
- Wear protective gear, including gloves, ear protection and a respirator.
- Lay a tarp over the project area to collect the debris and blasting material.
- Add the blasting material to the equipment.
- Attach the hose.
- Test the compressor with scrap material.
- Use smooth, back-and-forth strokes to blast the surface until you reach a clean outcome.
The Difference Between Dry and Wet Blasting
Dry blasting uses propelled media’s impact to affect the surface, while wet blasting cleans the surface through water propulsion. Wet blasting is the better choice when you need a more refined surface. However, you can use dry blasting to gather and filter debris from a surface.
Dry blasting machines can require direct pressure with a pressure pot or offer a suction system. Direct pressure machines are typically more costly than suction systems but provide a more straightforward method for pushing large abrasives.
Wet blast machines have a slurry pump system to push a water and abrasive mix through the blasting gun. Wet blasting machines offer consistent delivery and combine water and air for excellent results, making them desirable for many applications.
What to Know Before Your Next Abrasive Blasting Project
Now that you know where you can apply abrasive blasting techniques, here’s what you need to know before your next project.
Always measure the air pressure behind the blasting nozzle holder to create a more productive blasting process with minimal material waste. Ideally, the pressure should be steadily 110 pounds per inch (PSI), but anything above 100 should do the job. Pressures below 100 PSI will cause projects to take longer, wasting time and resources.
Always wear PPE, including masks or blasting-specific respirators, when handling abrasive media. Avoid using silica sand, if possible. Never operate your blasting unit inside confined spaces without ventilation. Before you begin your project, be sure the area is free of bystanders, animals or vulnerable items that could get damaged by excess abrasive media. Consider enrolling in formal blast training to learn the proper time-saving techniques. When blasting outdoors or disposing of materials, follow all local and federal environmental regulations.
Keep operational costs low by maintaining blasting equipment. This includes replacing blast nozzle heads as needed or when they wear and expand. Clean the nozzle in between materials and projects to keep it free of build-up or cross-contamination. Should you have to replace any large parts of your blasting equipment, seek manufacturer recommendations for optimal results.
Set yourself up for abrasive blasting success by creating the ideal blasting environment and choosing the right blast hose. The area where you perform abrasive blasting work should be well-ventilated. When sizing a blast hose, make sure it fits your equipment and projects. Undersized hoses will create a natural resistance that hinders performance and decreases pressure, leading to material waste.
Successful abrasive blasting relies on which materials you choose for your project. Different types include:
- Glass and ceramic: Ceramic grit and crushed glass create a softer finish, ideal for stainless steel. Glass beads are a popular blasting technique because they can clean, deburr and prepare surfaces without embedding anything into them. They’re also recyclable and reusable.
- Plastics and metals: Plastic and metal blasting materials include plastic grit, steel grit, steel shot, aluminum oxide, cut wire and copper slag. These materials are known for their strength and adaptability, perfect for heavy-duty industrial applications, granite and marble surfaces or deep etching. Some types are recyclable.
- Natural materials: Natural and organic blasting options include garnets, walnut shells, ground corn cobs and powder from ground apricot, peach and plum stones. Depending on the material and size of the pieces, these natural options can be softer alternatives for more sensitive surfaces.
- Specialty materials: Specialty materials, like dry ice and sodium bicarbonate, are suitable for projects like food service maintenance or rust and graffiti removal.
You might also consider specific blasting techniques for certain projects. For example, micro-blasting is the best method for detailed etching, wheel blasting is suitable for heavier materials and shot blasting helps operators achieve a deep clean.
Why Choose Finishing Systems for Your Abrasive Blasting?
At Finishing Systems, we’ve been helping businesses like yours optimize manufacturing results since 1972. We have the facilities, equipment and expertise to deliver the best outcome for your projects. Contact us for more information about our blasting services today.