Crushed Glass vs Coal Slag vs Garnet: Choosing the Right Blasting Media
Not all blasting media works the same.
Using the wrong media can damage the surface, cause coating failure, or shorten how long a job lasts. Even if everything looks clean at the end, the wrong media choice can create problems later.
Crushed glass, coal slag, and garnet are three of the most common blasting media used today. Each one has a purpose. Each one behaves differently.
Here’s how professionals decide which one to use…
Why Blasting Media Matters
Blasting media does more than remove rust or paint.
It also controls:
how rough the surface becomes
how clean the metal really is
how well paint or coatings stick
how long the finish lasts
Two surfaces can look the same but perform very differently based on the media used.
That’s why media choice matters.
Crushed Glass: Clean and Versatile
Crushed glass is made from recycled glass that’s broken into sharp particles.
It’s popular because it:
cuts evenly
creates a clean surface
leaves low contamination
is safer to dispose of
Crushed glass works well on:
steel
aluminum (with proper pressure)
automotive parts
restoration projects
It’s a good all-around option when you want clean results without being too aggressive.
Coal Slag: Fast and Aggressive
Coal slag is a byproduct of coal burning. It cuts faster and harder than crushed glass.
It’s good for:
thick coatings
heavy rust
industrial steel
large equipment
But it has downsides:
more dust
rougher surface if not controlled
higher chance of embedding material into the metal
Coal slag works best when speed is important and the surface can handle aggressive blasting.
Garnet: Consistent and Precise
Garnet is a natural mineral abrasive.
It’s known for:
consistent particle size
smooth, even surface profile
low dust
reusability in contained systems
Garnet is often used for:
high-spec industrial jobs
projects with strict coating requirements
situations where precision matters
It costs more, but in the right job, it delivers very controlled results.
There Is No “Best” Blasting Media
There is no single media that works best for every job.
The right choice depends on:
the type of surface
how bad the rust is
what coating will be applied
how smooth or rough the surface needs to be
Using the wrong media can:
damage the surface
cause paint to fail early
increase long-term costs
Professionals choose media based on the job—not habit.
Frequently Asked Questions
Q: Is one blasting media always better than the others?
A: No. Each media works best in different situations.
Q: Does more aggressive media mean better results?
A: Not always. Too much aggression can damage the surface.
Q: Can crushed glass remove heavy rust?
A: Yes, in many cases, but very heavy rust may need more aggressive media.
Q: Does blasting media affect paint life?
A: Yes. Media choice affects surface profile, which affects how well paint sticks.
Final Thought
Blasting media is not just filler in a machine.
It’s a tool.
Choosing the right one is the difference between:
a job that looks good for a few months
and one that lasts for years
Good surface prep starts with the right media.
Next up: PSI, CFM, and Nozzle Size Explained (In Plain English).
