> Resource Hub / Blog / What is the difference between shot and grit blast media?

What is the difference between shot and grit blast media? 

Shot blasting is a process that uses steel spherical media, to prepare surfaces. The rounded nature of the media creates a smooth or polished finish, making it ideal for applications where surface strength and uniformity are essential.

Common uses of shot blasting include:

• Surface cleaning: Removing rust, scale, and other contaminants.
• Stress relief: Strengthening metal through shot peening.
• Polishing: Achieving a smooth, uniform finish for aesthetic or functional purposes.

Shot blasting is widely used in industries like automotive, aerospace, and heavy machinery manufacturing.

In contrast, grit blasting uses angular media—such as aluminium oxide, or garnet, that cuts into the surface, creating a roughened texture. This makes it the go-to choice for tasks that require aggressive cleaning or surface preparation for coatings.

Grit blasting is commonly used for:

• Removing old paint, rust, or contaminants.
• Preparing surfaces for coatings or adhesives by increasing surface roughness.
• Cleaning delicate or detailed surfaces with softer media like walnut shells or plastic media.

Grit blasting is often used in industries like marine, construction, and infrastructure maintenance.

The choice between shot and grit blasting depends on the surface type, the finish required, and the equipment available.

• Durability: Steel shot lasts longer and can be reused multiple times.
• Polished Finish: Ideal for applications that require a smooth, dimpled surface.
• Surface Strengthening: Shot peening improves material durability by relieving stress.

• Versatility: With a wide range of abrasive options, grit blasting can handle everything from delicate surfaces to heavy-duty cleaning.
• Better coating adhesion: The rough texture created by grit blasting improves bonding for paints and coatings.
• Customisable: Media options include natural materials (garnet, walnut shells) and synthetic materials (aluminium oxide), allowing for tailored results.

When deciding which method to use, consider the following:

• Surface material and condition: Metallic surfaces may benefit from shot blasting, while more delicate materials may require softer grit media.
• Desired finish: For a smooth, polished look, choose shot blasting; for a rough texture to support coatings, go with grit blasting.
• Equipment compatibility: Ensure your blasting machine is compatible with the media type you plan to use.

In general, shot blasting machines are specifically designed to use spherical media, like steel shot. These machines rely on the smooth, rounded shape of the media to flow efficiently through the system, which includes features like turbines or wheels for propelling the shot. Using angular grit media could:

• The sharp edges of grit can cause damage to the machine’s internal components, especially turbines, blades, or wheels not designed to handle abrasives with angular shapes.
• Angular media doesn’t flow as smoothly, potentially disrupting the blasting process.

However, some machines are versatile or can be modified to handle both types of media. If you’re considering using grit media in a shot blasting machine, always:

• Consult the manufacturer to ensure the equipment is compatible or can be adapted.
• Use the correct settings and adjust machine parameters to suit the media type if permitted.

For most applications involving grit media, it’s recommended to use a grit blasting system, which is specifically designed to handle angular abrasives effectively and safely.

Proper disposal of used blast media depends on several factors, including the type of media and any contaminants it has removed during blasting. Here’s a general guide:

• Check local regulations: In the UK, councils and environmental agencies provide specific guidelines for disposing of abrasive materials, particularly if they contain hazardous substances such as lead paint or oil residue.
• Recycle if possible: Some media, such as steel shot or garnet, can be recycled and reused multiple times. Once it’s no longer effective, it may still be recyclable as scrap metal or aggregate.
• Separate contaminants: Used media often contains contaminants; therefore, proper separation ensures safer disposal and reduces environmental impact.
• Work with waste management services: For contaminated media or large quantities, consider partnering with an industrial waste disposal service to handle it safely and compliantly.

By planning for media disposal before starting a project, you can minimise environmental impact and stay compliant with regulations.

Both shot and grit blasting are invaluable tools in surface preparation, but their differences in media, application, and finish mean they are suited for different tasks. By understanding their unique advantages, you can select the right blasting technique for your project.

At Airblast Eurospray, we provide a comprehensive range of blast media, equipment, and training to help you achieve optimal results. Whether you’re looking for smooth finishes or roughened textures, we’ve got you covered.

Explore our full range of blast media and equipment today. Need help deciding? Contact our team for expert knowledge and guidance!