What Is Dry Ice Blasting?

Dry ice blasting is a cleaning and surface preparation process that uses compressed air to propel small pellets of dry ice (solid carbon dioxide) at high velocities onto a surface in order to remove contaminants, coatings, and debris. This method is often used in industrial and commercial applications to clean a wide range of surfaces. Here’s how dry ice blasting works:

The Production of Dry Ice

Dry ice is produced by compressing and cooling gaseous carbon dioxide (CO2) until it reaches a temperature of around -78.5°C (-109.3°F). This extreme cold causes the CO2 gas to transform directly into a solid state of matter. This form is otherwise known as dry ice. The dry ice is then extruded into small, cylindrical pellets or blocks, typically measuring around 3 mm (0.12 inches) in diameter.

Loading A Dry Ice Blasting Machine

The dry ice pellets are loaded into a specialized dry ice blasting machine, which is equipped with a hopper or container for storing the dry ice. When the dry ice blasting machine is activated, compressed air is used to accelerate the dry ice pellets to high velocities, typically between 150 to 300 meters per second (500 to 1,000 feet per second). The accelerated dry ice pellets are propelled through a nozzle or blast gun toward the surface to be cleaned.

How Dry Ice Cleans Part Surfaces

1. Thermal Shock: The high-velocity dry ice pellets impact the surface and cause thermal shock. The extreme cold of the dry ice (-78.5°C) causes the contaminants or coatings on the surface to contract and become brittle. This thermal shock helps to break the bond between the substrate and the contaminants.
2. Kinetic Energy: The kinetic energy from the impact of the dry ice pellets also contributes to the removal of contaminants. The force from the pellets can dislodge and lift away the contaminants.
3. Sublimation: As the dry ice pellets impact the surface, they sublimate, meaning they change directly from a solid to a gas without passing through the liquid phase. This sublimation process creates small gas explosions that help dislodge and lift off the contaminants without leaving any residual abrasive media behind.

An Environmentally Conscious Choice

Unlike other blasting methods, dry ice blasting produces no secondary waste since the dry ice sublimates into carbon dioxide gas. The removed contaminants and debris can be collected with a vacuum system or allowed to dissipate into the air safely. There is no need for additional cleanup, and the process is environmentally friendly.

What Dry Ice Blasting Excels At

Dry ice blasting is suitable for a wide range of applications, including cleaning machinery, eliminating corrosion and contaminates, and for removing grease in certain instances. If you have a larger dry ice blaster, you can remove paint and other coatings too. The place where dry ice blasters make sense is in situations where cleanliness, efficiency, and the absence of chemicals or water is necessary.

All this being said, dry ice blasting is not typically used as a form of surface treatment. When blasting at high pressures, this process can roughen the surface, but the pellets are soft in comparison to the metal. For a standard dry ice blaster, you can expect comparable results to a pressure washer but without all the cleanup.

What Dry Ice Blasting Struggles At

Dry ice blasting equipment can be expensive to purchase and maintain. This initial investment cost can be a barrier for some businesses, especially smaller ones. Then the cost of dry ice itself can add up quickly as it has no longevity and is a single use abrasive. Additionally, the dry ice pellets must be used within a certain date of being opened, typically 3 days, as use past this date can cause damage to your machine. Dry ice blasting also is less effective at removing very thick or strongly adhered coatings or contaminants. It also struggles to clean surfaces contaminated with oils or grease. In such cases, multiple passes over the part or degreasing with a parts washer may be required.