Shot Blasting and Sandblasting Media Explained
When people ask for sandblasting, they usually picture sand. In reality, the material used in blasting is called the media, and there are lots of different types. Choosing the right one is the most important decision on any job, because it decides how fast the work goes and whether your surface is left clean or damaged.
I use COSHH-approved media on every job and match it to what's being cleaned. Here's a plain English guide to the main types and what each one is for.
Why the media matters so much
Think of media like sandpaper. A coarse grade strips thick rust off a steel beam in minutes, but it would ruin a thin car panel or a piece of soft stone. A fine, soft grade is gentle, but it would take all week to get through heavy scale.
Pressure matters too, and it works hand in hand with the media. A good blaster adjusts both for every surface. That's why one company can leave your gates looking brand new while another leaves them pitted and scarred. I cover the wider picture in what's the difference between blast cleaning and sandblasting.
Glass beads
Glass beads are small, round and smooth. They clean and brighten without cutting into the surface, which leaves a soft satin finish. They suit delicate jobs such as thin car panels, alloy parts and fine detail.
Walnut shell
Walnut shell is a soft, natural media. It's gentle enough to clean paint, grime and old coatings from surfaces that would be marked by anything harder. It works well on engine parts, delicate metalwork and timber, and it's one of the safest choices for wood, as I explain in sandblasting wood beams and doors.
Crushed stone
Crushed stone is a harder, sharper media for heavier cleaning. It cuts through rust, thick paint and tough build-up on solid metal. It's a good choice for strong, thick steel where speed matters, but too harsh for anything thin or soft.
Steel grit and shot
Steel is the heavyweight. Shot is round and grit is angular, and both clean thick steel quickly and leave a rough, keyed surface that paint and coatings grip well. It's used on structural steel, chassis, heavy machinery and anything that needs a deep clean and a strong bond for the finish.
Which media for which job
| Job | Typical media |
|---|---|
| Thin car panels and alloy | Glass beads or walnut shell |
| Engine parts and delicate metalwork | Walnut shell or glass beads |
| Old brick and soft stone | Soft media at low pressure |
| Wood beams and doors | Walnut shell at low pressure |
| Gates and railings | Matched to the metal, from soft to firm |
| Thick steel, chassis and machinery | Crushed stone or steel grit |
Shot blasting versus sandblasting
People use these terms for the same kind of work. Strictly, shot blasting uses steel shot and sandblasting uses sand, but modern blast cleaning covers all of it. The name matters less than the method. What counts is whether the media, pressure and technique are right for your surface.
How to check you're getting the right media
Ask the company what they would use on your item and why. A good answer is specific. If you get "the same as for everything", be wary. Our guide on how to choose a sandblasting company has the other questions worth asking.
Frequently asked questions
Is sand still used for sandblasting?
Rarely. Modern blasting uses a range of media that are safer to use and give more control. Silica sand in particular has health risks, which is why approved alternatives are used.
Which media is gentlest?
Walnut shell and glass beads are among the gentlest. Pressure also plays a big part, so a gentle media at high pressure can still cause damage.
Does the media affect the cost?
It can. Heavier jobs and different media change how long the work takes. You can read more about this in how much sandblasting costs in Dorset.
Related reading
- How to remove rust from a classic car chassis
- Sandblasting vs chemical stripping vs wire brushing
- Sandblasting old iron gates and railings
If you're unsure what your project needs, call me on 01202 526649 or use the contact page. You can also see the work I take on on the services page.