Abrasive blasting is a finishing process, where a stream of abrasive material – also known as abrasive media – is propelled onto the surface of a workpiece. It serves various purposes, such as removing contaminants or previous coatings, altering the shape of an object, and smoothing or roughening a surface.
There are various types of abrasive materials on the market, which is great in terms of finding something suitable for your project. However, knowing which is the best choice can be easier said than done.
Here, the team at Surface Finishing Equipment Group (SFEG) explain a little more about the different abrasive options available, and offer a few useful hints on choosing the right material for the task at hand.
Different types of blasting media
At SFEG, we supply two types of abrasive media:
- Expendable abrasives – made from by-products, expendable blast media is intended for one-time use only. It cannot be recovered or recycled, and is often used with mobile blast pots.
Examples include Arablast Medium, Arablast Fine, garnet, iron silicate, JBlast SC, olivine, etc.
- Reusable abrasives – typically used in blast rooms and cabinets, reusable blast media is recyclable and can be used again and again, helping to reduce waste and operating costs.
Examples include aluminium oxide, glass bead, profilium, and steel shot.
To help you determine the most suitable abrasive for the job, let’s take a look at 3 common types of abrasive media, including their uses and pros and cons.
1. Glass bead
A glass bead is a less aggressive type of abrasive that offers a uniform surface finish without changing the overall dimensions of a workpiece. It can be used for peening, deburring, removing rust, paint, and scale, polishing materials, and preparing metal surfaces for a fresh layer of paint or powder coating.
Pros of glass beads:
- Provide an attractive finish
- Environmentally-friendly (reusable media)
- Suitable for thin, delicate parts
- Chemically inert
Cons of glass beads:
- May take slightly longer to get the job done, particularly on tougher materials
- Unable to etch the surface
2. Aluminium oxide
As a more aggressive blasting material, aluminium oxide offers exceptional strength and faster results. With its angular yet lightweight design and sharp edges, aluminium oxide is often used in grinding, polishing, edge rounding, paint removal, and surface preparation for paint.
Pros of aluminium oxide:
- Exceptional durability – ideal for tougher metals
- Light, so won’t damage thin surfaces
- Cost-effective
- Recyclable
Cons of aluminium oxide:
- May be too aggressive for certain surfaces
- Often harsh on abrasive blasting equipment
3. Plastic
Plastic abrasive media is the go-to choice for delicate applications or cleaning. When compared to other blast media, plastic is softer, and can remove unwanted materials without harming the substrate underneath. It’s commonly used for paint stripping, mould removal, deburring, and deflashing.
Pros of plastic abrasive media:
- Durable and free from silica
- Offers surface-level abrasion, ensuring minimal damage to the underlying material
- Produces low levels of dust
- Comes in a variety of shapes and sizes
Cons of plastic abrasive media:
- Usually doesn’t work well on hard metals or for finishing applications
- Can take more time on softer materials
4 tips to help you choose abrasive blasting media
Though it helps to know a little bit about the different types of blast media, it’s worth bearing the following in mind…
#1 If in doubt, opt for softer abrasives
Unsure whether the surface you’re blasting can handle aggressive abrasives? You’re better off starting with a gentler material – something like walnut shells or corn cobs, as they won’t etch the surface too much.
#2 Choose glass beads for a smooth finish
Want to achieve a smooth, bright finish? Then go for glass beads. These are made from fine soda-lime glass, which places minimal stress on the surface, and they can be recycled up to 100 times before they need replacing.
#3 Use aluminium oxide to remove paint
Aluminium oxide is harder and sharper than glass beads, making it ideal for paint removal and general cleaning jobs, preparing the surface for a final finish. This abrasive media can be used for glass etching, too.
#4 Make plastic your first choice for automotive and aerospace applications
Given that plastic is extremely soft, it’s a superb choice for removing contaminants from fibreglass parts and delicate surfaces, which are frequently used to manufacture automotive, aerospace, and marine products. Plastic blast media won’t etch or strip the part, either.
Need an expert opinion?
If you have any further questions regarding abrasive media, or you’re unsure which material is best for your project, why not get in touch? You can either email sales@sfeg.co.uk or fill out our online enquiry form, and we’ll get back to you as soon as we can.
