How does dry ice blasting work?

Dry ice blasting works by combining three physical effects that occur in milliseconds when solid CO2 pellets strike a contaminated surface. Cold Jet summarizes the process with the acronym ICE: Impact, Cold, and Expansion. Impact is the kinetic energy effect — dry ice pellets accelerated by compressed air through specially designed nozzles at supersonic speeds strike the surface. Cold is the thermal effect — the -109°F (-78.9°C) temperature of dry ice causes the contaminant to embrittle, breaking its bond with the substrate. Expansion is the thermal-kinetic effect — dry ice pellets sublimate on impact, expanding up to 800 times in volume and lifting the contaminant off the surface. Unlike other media blasting methods that rely primarily on kinetic force, dry ice blasting uses all three mechanisms together, which makes it both effective and non-abrasive.

What are the three primary factors that make dry ice blasting work?

Dry ice blasting combines three primary factors to remove contaminants. First, pellet kinetic energy: dry ice accelerated through a nozzle at supersonic speeds collides with the substrate, creating a kinetic effect that has the largest contribution when substrates are at ambient temperature or below. Second, the thermal shock effect: the -109°F (-78.9°C) temperature of dry ice causes thermodynamic shock that embrittles and shrinks the contaminant, producing micro-cracks that break the bond between contaminant and surface. Third, the thermal-kinetic effect: dry ice pellets sublimate from solid to gas on impact, expanding 800 times in volume in milliseconds and creating a 'micro-explosion' that lifts contaminant particles away from the substrate.

Why is dry ice considered non-abrasive when blasted at high velocity?

Dry ice is non-abrasive for two reasons. First, dry ice pellets register only 1.5 to 2 on the Mohs hardness scale, making them significantly softer than other blasting media like grit, sand, or plastic media beads. Even at high impact velocities and direct head-on impact angles, the kinetic effect of solid CO2 pellets is minimal compared to harder media. Second, the dry ice pellet changes phase from solid to gas almost instantaneously upon impact, so very little impact energy is transferred into the coating or substrate. The combination of low hardness and rapid phase change is what makes dry ice blasting safe for sensitive surfaces, electronics, and precision-machined components.

What is the thermal shock effect in dry ice blasting?

The thermal shock effect is the second of three mechanisms in dry ice blasting. When dry ice at -109°F (-78.9°C) contacts a warmer contaminant, the rapid heat transfer creates thermodynamic shock that causes the contaminant to embrittle and shrink. The instantaneous sublimation of dry ice on impact absorbs maximum heat from the very thin top layer of the contaminant due to the latent heat of sublimation. This rapid heat transfer creates an extreme temperature differential between successive micro-layers within the contaminant, producing localized high shear stresses that cause micro-cracking. The micro-cracks propagate between layers and lead to bond failure between the contaminant and the substrate surface.

What is the thermal-kinetic effect in dry ice blasting?

The thermal-kinetic effect is the third mechanism in dry ice blasting and is responsible for lifting contaminants off the surface. On impact, combined impact energy dissipation and rapid heat transfer cause the dry ice particles to sublimate, expanding instantly into CO2 gas. During this phase transition from solid to gas, the volume of dry ice expands up to 800 times in a few milliseconds, creating a 'micro-explosion' at the point of contact. Because dry ice has very little rebound energy, the gas expands outward along the surface, creating an 'explosion shock front' — an area of high pressure focused between the surface and the thermally fractured contaminant particles. This shock front provides an efficient lifting force to carry contaminant particles away from the substrate.

How fast does dry ice expand when it impacts a surface?

When a dry ice pellet impacts a surface, it sublimates from solid to gas and expands up to 800 times its original volume in a few milliseconds. This rapid volumetric expansion creates an 'explosion shock front' at the point of impact that propagates outward along the surface, generating high pressure between the substrate and any thermally fractured contaminant particles. The result is an efficient lifting force that carries contaminant particles away from the surface without abrasion. The 800x expansion happens essentially instantaneously, which is why dry ice blasting cleaning happens in milliseconds rather than seconds.

Why does dry ice cause micro-cracking in contaminants?

Dry ice causes micro-cracking through an extreme thermal gradient. When dry ice at -109°F (-78.9°C) contacts a warmer contaminant, heat transfers rapidly from the contaminant's top layer into the dry ice due to the latent heat of sublimation. This creates a large temperature differential between successive micro-layers inside the contaminant. The sharp thermal gradient produces localized high shear stresses, which depend on the contaminant's thermal conductivity, thermal coefficient of expansion and contraction, and the thermal mass of the underlying substrate. The high shear over a very brief period causes rapid micro-cracking between layers, ultimately leading to bond failure between the contaminant and the substrate.

What does the ICE acronym stand for in dry ice blasting?

ICE is the acronym Cold Jet uses to describe the three primary mechanisms of dry ice blasting. I stands for Impact: the kinetic energy effect created when soft dry ice pellets accelerated by compressed air through specially designed nozzles strike the contaminated surface at supersonic speeds. C stands for Cold: the thermal effect created by the -109°F (-78.9°C) temperature of dry ice, which causes contaminants to embrittle and helps break the bond between substrate and contaminant. E stands for Expansion: the volumetric expansion of dry ice pellets as they sublimate from solid to gas, which lifts the contaminant off the surface. The ICE framework is a memorable way to understand why dry ice blasting works differently from media blasting methods that rely on kinetic force alone.

Learn everything you need to know about using compressed air for dry ice blasting, including mobile air compressors, aftercoolers, CFM, PSI, and more!

Key Takeaways:

Top-tier dry ice blaster performance depends on a steady supply of compressed air that is filtered, dry, and cool, delivered at the CFM and PSI levels recommended for your machine and nozzle. This air can come from either a facility air line or an industrial air compressor.

Using dry, high-quality compressed air is an essential part of effective dry ice blasting. Too often, new users of dry ice blasters do not account for the type of compressed air supply needed to adequately operate their machine. This misunderstanding leads to frustration for users, causing misinformed claims that dry ice blasters are not functioning properly, are prone to ice blockages, or are underpowered for cleaning contaminants.

This guide will provide an overview of using compressed air specifically for dry ice blasting, including air requirements, air compressors, and general tips for successful dry ice blasting sessions.

Compressed Air Metrics: What is the Difference Between CFM and PSI?

One of the most critical elements of using the correct compressed air for your dry ice blaster is understanding how to measure its power: Cubic Feet Per Minute (CFM) and Pounds Per Square Inch (PSI). These two factors tell the user the amount of air that is flowing through the dry ice blaster and the pressure behind that air.

Cubic Feet Per Minute (CFM)

CFM measures the overall volume of air flowing through the dry ice blasting system. The CFM required is contingent upon two primary factors:

Blast Pressure Range: A dry ice blaster operating at lower blast pressure ranges will require less CFM. If the blast pressure is increased, the blaster will require higher CFM. When recommending required CFM, Cold Jet standardizes blast pressure at 80 PSI. At 80 PSI, dry ice blasters typically need between 50 and 165 CFM to operate efficiently. Microparticle dry ice blasters can consume as little as 12 CFM during delicate work.
Nozzle: The nozzle used during blasting is a primary factor in determining required CFM. Different nozzles require more or less CFM to operate effectively. For example, when using the Cold Jet MC31 MicroClean2 nozzle, it requires 50 CFM at 80 PSI. If you lower the blast pressure to 40 PSI, you're only consuming 25 CFM.

Pounds Per Square Inch (PSI)

PSI measures the physical force of the air being pushed through the blaster nozzle. The common rule of thumb to remember is that higher pressure equals greater impact. The standard baseline for most industrial dry ice blasters is an operating range between 20 and 250 PSI. High-pressure models can operate up to 300 PSI for more aggressive cleaning tasks and most blasters can operate at as little as 20 PSI.

To ensure effective operation, your compressed air source must supply adequate air pressure and volume. Plant air at most manufacturing and industrial facilities will provide sufficient air volume and pressure. If you're using a mobile air compressor, ensure it's capable of providing sufficient air based on your machine's recommended air requirements.

Compressed Air Requirements by Equipment Class Table

View full Compressed Air Requirements by Equipment Class specifications

Compressed Air Requirements by Equipment Class
Equipment Class	Airflow Range (CFM)	Blast Pressure Range (PSI)	Typical Application
MicroParticle Blasters	12 – 70 CFM	20 – 140 PSI	Delicate detailing, electronics, plastic mold cleaning
Standard Commercial Blasters	50 – 165 CFM	20 – 250 PSI	General maintenance, mold remediation, automotive
Heavy-Duty Industrial Blasters	50 – 165 CFM	20 – 300 PSI	Thick bitumen, industrial coatings, heavy slag

* All CFM ranges are based at operating at 80 PSI blast pressures. If the blast pressure is reduced, the CFM required is also reduced.

What Sources of Compressed Air Should Be Used in Dry Ice Blasting?

There are two common forms of compressed air sources used by dry ice blasters: facility compressed air (plant air) and mobile air compressors.

Choosing to use either a diesel-powered mobile air compressor or plant air will depend on the work environment and the type of surfaces being cleaned.

Facility air compressor

Facility Compressed Air Lines (i.e., “plant air”)

Most facilities can supply dry ice blasters with sufficient CFM and PSI through the air lines built into the building. Because factories, plants, and processing facilities run a variety of tools that depend on a pneumatic system, they're designed to maintain a consistent flow of filtered dry air for daily operations. Connection points are usually available along walls and corridors for easy access.

Before starting a cleaning session, ensure your plant air can supply enough CFM and PSI to run your dry ice blaster along with any other tooling drawing on the same line, such as pneumatic tools. The more tools using the system at once, the greater the total demand—so it is worth confirming that there is enough capacity to support everything running concurrently.

diesel air compressor

Mobile Air Compressors

A diesel-powered mobile air compressor is the best choice when cleaning tasks fall outside the reach of a facility's compressed air line, or take place in remote or outdoor work environments. A mobile unit is also a good option when you need more capacity than the facility's air line can provide for the dry ice blaster.

If you're using a mobile air compressor for indoor cleaning tasks, place the compressor outside for proper exhaust ventilation and noise reduction, then run a longer air hose to the dry ice blaster inside. When running a longer length of hose, make the proper CFM adjustments to account for the additional friction air drops.

Can You Use a Small Shop Air Compressor for Dry Ice Blasting?

While using a small shop air compressor is not recommended for dry ice blasting, certain 35-horsepower rotary screw air compressors that run on single-phase electricity can work for light blasting activity.

Most standard small shop air compressors (which typically deliver a maximum of 15 CFM at 90 PSI and have 80-gallon tanks) cannot be used for commercial dry ice blasting as they lack the continuous air volume required to achieve optimal blaster performance.

Air Quality Requirements for Dry Ice Blasting: Clean, Dry, and Ambient

To optimize dry ice blasting performance and protect sensitive substrates, compressed air should be clean, dry, and oil-free. Filtered, dry air at ambient temperatures and free of airborne contaminants is optimal for dry ice blasting for these key reasons:

Filtration: Air impurities can negatively affect the dry ice particles or cause abrasive surface damage to substrates being cleaned.
Dryness: Dry ice is extremely cold at -109°F (-78.5°C), so any moisture left in unconditioned compressed air can freeze when it reaches the dry ice inside the machine. That ice binds the pellets together, which can clog the feed system, foul the dosing rotor, and interrupt the flow of dry ice to the nozzle. Humid environments make this occurance more likely, which is why an aftercooler or air dryer is recommended when moisture is a concern.
Ambient Temperature: Air that is too hot can cause dry ice particles to prematurely sublimate (transition from a solid to a gas) before they exit the nozzle. Compressed air must be cooled down to be within 15°F of ambient temperatures to be optimized for dry ice blasting.

Why You Need an Aftercooler with Diesel Air Compressors for Dry Ice Blasting

While facility air lines are pre-conditioned for blasting, diesel air compressors create hot, humid air that contains impurities. In the case of mobile air compressor units, additional equipment is needed to ensure the air being fed to the dry ice blaster is fully optimized. An aftercooler is an essential device that must be used in conjunction with any mobile industrial air compressor to remove excessive heat from the air, bringing it down to ambient temperature before it enters the dry ice blaster. Weekly aftercooler rentals run about $150 to $350, while brand-new purchases range from $3,500 to $6,000.

Aftercooler with dry ice blaster

How Does Friction Pressure Drop Affect Dry Ice Blaster Performance?

A key metric in controlling compressed air pressures for sustained dry ice blasting is the difference between the marketed CFM and PSI rating of an air compressor and its real-world performance. As compressed air travels through the blasting system and down the length of the hose, it encounters internal friction. This friction causes a pressure drop below the compressor’s nominal rating, which can drastically reduce cleaning efficiency.

For example, if a task requires 100 CFM at 80 PSI and your compressor is rated for exactly those numbers, the nozzle will see less than 80 PSI in practice because air loses pressure to friction as it travels through the hoses, fittings, and machine. Longer or narrower hoses increase that friction and compound the loss. A good practice is to choose a compressor rated above your machine's minimum CFM and PSI requirements so you still meet them at the nozzle after losses.

Mobile Air Compressor Types for Dry Ice Blasting

If dry ice blasting tasks require a more mobile source for compressed air, there are multiple mobile industrial air compressor options to meet contractor and maintenance technician needs:

Air Compressor Types for Dry Ice Blasting

Air Compressor Classification	Description	Rated Air Output (CFM & PSI)	Estimated Capital Cost (New)	Estimated Capital Cost (Used)	Rental Price Range
Compact Rotary Screw	Highly portable units designed to have a small footprint. Powered by either gasoline or diesel fuel. Typically mounted on a wheeled cart. Fits in the back of work trucks and vans.	45–80 CFM @ 100+ PSI	$11k to $14k	$5k to $8.5k	Rarely rented out; typically purchased
Tow-Behind Commercial	Easily towed behind work trucks and vans on single-axle trailers. Powered by diesel fuel. Workhorse performance capabilities. Readily available as rentals.	100 to 185 CFM @ 125 PSI	$26k to $35k	$7.5k to $18k	$150 to $250 daily; $800 to $1000 weekly
Tow-Behind High-Capacity Industrial	Towed behind work trucks on multi-axle trailers. Powered by diesel fuel. Considerably more performance capabilities than standard commercial models. Often supports two dry ice blasters at once.	375 to 450+ CFM @ 125 to 200+ PSI	$68k to $82k	$22k to $35k	$225 to $350 daily; $1000 to $1500 weekly; $3000 monthly
Skid-Mounted Utility	Mounted on the back of work trucks, flatbeds, or within an enclosed trailer. Powered by diesel fuel. Performance capabilities on par with tow-behind commercial models.	110 to 300+ CFM @ 100 to 150+ PSI	$27k to $40k	$12k to $22k	Not rented; custom rigs for work trucks or trailers

View full Air Compressor Types for Dry Ice Blasting specifications

Air Compressor Types for Dry Ice Blasting
Air Compressor Classification	Description	Rated Air Output (CFM & PSI)	Estimated Capital Cost (New)	Estimated Capital Cost (Used)	Rental Price Range
Compact Rotary Screw	Highly portable units designed to have a small footprint. Powered by either gasoline or diesel fuel. Typically mounted on a wheeled cart. Fits in the back of work trucks and vans.	45–80 CFM @ 100+ PSI	$11k to $14k	$5k to $8.5k	Rarely rented out; typically purchased
Tow-Behind Commercial	Easily towed behind work trucks and vans on single-axle trailers. Powered by diesel fuel. Workhorse performance capabilities. Readily available as rentals.	100 to 185 CFM @ 125 PSI	$26k to $35k	$7.5k to $18k	$150 to $250 daily; $800 to $1000 weekly
Tow-Behind High-Capacity Industrial	Towed behind work trucks on multi-axle trailers. Powered by diesel fuel. Considerably more performance capabilities than standard commercial models. Often supports two dry ice blasters at once.	375 to 450+ CFM @ 125 to 200+ PSI	$68k to $82k	$22k to $35k	$225 to $350 daily; $1000 to $1500 weekly; $3000 monthly
Skid-Mounted Utility	Mounted on the back of work trucks, flatbeds, or within an enclosed trailer. Powered by diesel fuel. Performance capabilities on par with tow-behind commercial models.	110 to 300+ CFM @ 100 to 150+ PSI	$27k to $40k	$12k to $22k	Not rented; custom rigs for work trucks or trailers

Final Takeaways: Using the Right Source of Compressed Air Makes or Breaks Dry Ice Blaster Performance

Using a proper industrial air compressor or plant air that delivers adequate CFM and PSI for your dry ice blasting needs is essential to achieving effective cleaning results. If using a diesel air compressor, make sure an aftercooler is in place to purge the incoming air of excessive heat, moisture, and impurities, which keeps the dry ice blaster from suffering freeze-ups or feed mechanism malfunctions. Keep in mind that friction causes pressure to drop between the compressor and the nozzle, so account for those losses—along with any other tools drawing on the same supply—when confirming your air source is sufficient. To verify your compressed air supply is adequate, check the air volume and pressure requirements of your dry ice blaster or consult with a Cold Jet representative.

Need more advice on which air compressor to use for your dry ice blaster? Contact Cold Jet to make sure your compressed air setup is engineered for peak performance!

The Comprehensive Guide to Compressed Air for Dry Ice Blasting