Buyer’s Guide to Compressors for Sand / Grit Blasting
Your blasting machine is only as good as the compressor behind it. Sand and grit blasting demand high volumes of air to maintain consistent pressure and abrasive flow. Choosing a compressor that’s too small leads to slow cleaning, pressure drops, and wasted time.
This guide breaks down what to look for in a blasting compressor — with a focus on airflow (CFM), pressure, portability, and air quality.
1. Airflow (CFM) and Pressure (PSI/bar)
Airflow (CFM) = the “horsepower” of your blasting setup. The higher the CFM, the more abrasive you can move through the nozzle.
Pressure (PSI/bar) = the “torque.” Higher pressure delivers stronger impact to strip coatings, rust, or contaminants.
Both must work together for efficient blasting. Too little airflow, and even high pressure won’t clean effectively.
2. How Much Airflow Do You Need?
Applied and other industry guides agree:
140 CFM — the minimum for effective blasting. Anything less is too slow.
180 CFM — ideal for medium-duty work such as car bodies, tractors, or trailers.
260–500 CFM — needed for heavy-duty, high-volume blasting like construction steelwork, ship hulls, or long-hose setups.
👉 Nozzle size matters: An 9,5mm nozzle can require 200+ CFM at 7 bar, and larger nozzles even more. Always size your compressor to your nozzle and job.
3. Compressor Types
Portable compressors
✅ Easy to tow to site, great for contractors
✅ Compact footprint
❌ Smaller models limited to light blasting
Stationary compressors
✅ High airflow for continuous blasting
✅ Best for blast rooms and workshops
❌ Require permanent installation and space
4. Air Treatment — Aftercoolers & Moisture Separators
Moisture is the enemy of blasting. Compressing air generates heat and condensation, which can cause abrasive to clog.
Aftercoolers cool compressed air and reduce water vapour.
Moisture separators remove liquid water from the airstream.
The result:
Consistent abrasive flow
Less nozzle wear
Better blasting efficiency
Most quality mobile compressors come with these fitted as standard.
5. Nozzle Size vs Compressor Requirement
| Diameter (mm) | Airflow (CFM) | Pressure (bar) | Typical Use |
|---|---|---|---|
| 3.2 | 21 | 6.9 | Very light blasting, detail work, small parts |
| 4.8 | 45 | 6.9 | Light-duty blasting, occasional small jobs |
| 6.4 | 80 | 6.9 | Small contractors, light rust/paint removal |
| 8.0 | 140 | 6.9 | General-purpose blasting, automotive & machinery |
| 9.5 | 200 | 6.9 | Medium-duty blasting, structural steel, trailers |
| 11.0 | 255 | 6.9 | Heavy-duty blasting, thick coatings, ship work |
| 12.7 | 340 | 6.9 | Industrial blasting, high productivity jobs |
| 16.0 | 550 | 6.9 | Large-scale projects, continuous blasting |
| 19.0 | 800 | 6.9 | Shipyards, bridges, industrial-scale blasting |
Smaller nozzles (up to 5mm) can run on lower-CFM compressors, but are slower and less efficient for larger surfaces.
Most contractors use 8mm+ nozzles — this is where compressors in the 140+ CFM range become essential.
Heavy-duty nozzles (11mm+) demand 255+ CFM compressors, typically towable diesel units for industrial blasting.
Always add 20–25% extra airflow capacity to account for hose length, moisture separators, and real-world inefficiencies.
5. Other Key Considerations
Duty cycle — blasting is continuous, so pick compressors designed for long runtimes.
Noise & power — larger compressors may need three-phase power and produce more noise.
Maintenance — choose units with easy access to filters, separators and valves.
Future-proofing — size up slightly to handle bigger jobs or larger nozzles in the future.
Key Takeaways
CFM and PSI are crucial—match them to your blasting equipment’s specs.
Nozzles - get the right nozzle for your use case that works with your compressor
Always size up—undersized units lead to weak performance and breakdowns.
Don’t overlook air treatment, noise, and maintenance accessibility.
The right compressor ensures fast, smooth blasting and durable equipment—cash-saving and efficient.
👉 Need help choosing the perfect compressor for your sandblasting setup? Reach out to CoolBlast—we’ll help match the right power, capacity, and quality to your needs.