What is Better for Removing Contaminants: Dry Ice Blasting or Sandblasting?

Key Takeaways:

Among the most popular industrial cleaning methods available, dry ice blasting and sandblasting are very different in their respective mechanisms for cleaning contaminants from surfaces. Dry ice blasting uses the three-step process of kinetic impact, thermal embrittlement, and rapid gas expansion to separate contaminants from substrates.

Sandblasting, on the other hand, uses pure kinetic impact with a grinding effect to scrape contaminants away. While sandblasting has long been a method for industrial cleaning, it is very messy and time-consuming, whereas dry ice blasting is quick and efficient.

What is Sandblasting?

Sandblasting is one of the most abrasive forms of industrial cleaning, utilizing sand-like media often called “grit.” The grit is accelerated at high velocity to remove contaminants from substrates through kinetic impact with an added mechanical grinding action. The type of grit media used can range from fine to coarse, depending on the contaminant type being cleaned. Often, sandblasting is chosen for its ability to clean deep-pitted corrosion and rust.

Grit media is loaded into a pot that is pressurized so the grit and air can travel together through the hose. The grit is pushed into the pressurized hose through a metering valve to prevent clogging and to ensure an even flow of media. The grit-air mixture is then sent through the hose to a spray applicator using compressed air where it is blasted out through a specialized nozzle at high velocity.

Upon impact, the grit media aggressively erodes the contaminant particles away until they have all cleared the substrate. With sandblasting, the results are immediate and create surface profiling (microscopic peaks and valleys formed in the surface).

What is Dry Ice Blasting?

Dry ice blasting accelerates high-density dry ice pellets (recycled solid CO₂) at high velocity to remove contaminants from surfaces through kinetic impact, thermal embrittlement, and rapid gas expansion. These processes take place simultaneously and within milliseconds, breaking the bonds that keep contaminants stuck to substrates.

To start blasting, dry ice pellets are loaded into the insulated hopper and systematically agitated to prevent clumping and blockages. Compressed air pushes the dry ice pellets through an insulated hose to the blasting applicator where it is ejected outward through a specialized nozzle. When the pellets impact the surface, the CO₂ sublimates (goes from a solid to a gas instantly) and expands rapidly, lifting the contaminant particles away.

Comparative Analysis: Dry Ice Blasting vs. Sandblasting

The following table highlights the operational and differences between dry ice blasting and sandblasting:

How is Sandblasting Similar to Dry Ice Blasting?

Dry ice blasting and sandblasting share several similarities in how they both clean surfaces:

• Dislodge contaminants with kinetic energy:

Both dry ice blasting and sandblasting use particulate impact at high velocity to forcibly break contaminant bonds, but with a major difference: abrasive media used in sandblasting also enacts an aggressive scraping action while dry ice blasting uses cryogenic properties to embrittle contaminants for removal.

• Quick cleaning:

Dry ice blasting and sandblasting remove contaminants from surfaces within several minutes and do not require additional preparation to achieve cleaning.

• Cleans many different types of contaminants:

Dry ice blasters like the Cold Jet Aero 2 ULTRA series can adjust settings for pellet size, PSI, and dry ice consumption rate to adapt to different contaminants. Sandblasting uses various sand media (ranging from fine to coarse in texture) to accommodate a variety of applications.

• Suitable for a wide variety of surfaces:

Both methods can clean metal, glass, concrete, wood, and stone.

• Popular in similar industries:

Both cleaning technologies are well-received in the mold and fire remediation, restoration, automotive, oil & gas, and manufacturing industries.

What Are the Limitations of Sandblasting?

Sandblasting is very effective at stripping paint, varnish, and heavy corrosion, but this abrasive blasting method has certain limitations in its use for cleaning tasks:

1. Sandblasting creates significant secondary waste that must be cleaned up afterwards:

Sandblasting uses a tremendous amount of grit media for cleaning, all of which becomes a secondary waste product (ranging from 70-800 lbs. per hour, depending on blasting needs such as nozzle size, PSI, and contaminant being removed). Once the blast media mixes with contaminants, it becomes an unsafe exposure risk and must be properly gathered and disposed of responsibly.

Since the grit media is dispersed all over the immediate work environment, sandblasting requires users to take extensive measures to contain the waste so as not to pollute the surrounding environment or affect the health of others. Additionally, the disposal costs for contaminated sandblasting media can vary depending on the following factors:

• The amount of grit to be disposed of
• The level of toxicity in the grit (hazardous or non-hazardous)
• Transportation needs
• Container needs
• Testing and analysis of media samples for toxicity

Contaminants such as lead paint, oil, chemicals, or corrosion can raise disposal costs significantly.

Where dry ice blasting has a competitive advantage:

No secondary waste product is produced in the cleaning process, no matter what surface or contaminant type is being cleaned. The CO₂ pellets sublimate upon impact and do not affect the surrounding environment.

2. Sandblasting preparation and cleanup take significantly more time than cleaning:

While the actual time needed for individual sandblasting tasks can vary, preparation and cleanup often take as much time as the blasting itself, and frequently more. Sandblasting is one of the most time-intensive industrial cleaning methods due to the time required to account for the waste generated.

Operators must engage in containment measures, which include setting up tarps, tents, plastic lining sheets, or blast shields before sandblasting to protect sensitive surfaces and equipment. Additionally, a significant portion of time must be spent collecting and disposing of the contaminated grit afterwards. Depending on the cleaning task, cleanup time can range from a few hours to more than a day.

Where dry ice blasting has a competitive advantage:

Since there is no secondary waste product produced during dry ice blasting, preparation and cleanup time is minimal. Preparation includes positioning and setting up the dry ice blaster, aftercooler, and compressed air source. When necessary, any cleanup is limited to sweeping or vacuuming up any contaminant pieces that might have landed on the floor or work area.

3. Sandblasting is too abrasive for sensitive substrates and parts:

Sandblasting grit is inherently more abrasive than other forms of blasting media. While this aspect is desirable in certain situations such as paint, varnish, and corrosion removal, it cannot be used to clean more sensitive substrates and objects such as thin metals like aluminum, plastics, rubber, or electronics.

Where dry ice blasting has a competitive advantage:

Dry ice blasters like the Cold Jet Aero 2 PCS ULTRA can adjust dry ice particle sizing, air consumption, and dry ice consumption rate to adapt to the surface or object being cleaned to ensure it is not damaged during the cleaning process.

4. Sandblasting generates significant heat during blasting:

Alongside abrasiveness, sandblasting generates a significant amount of heat due to the friction created when the grit media impacts the substrate at high velocity. The heat inflicted upon the surface can cause significant damage to certain surfaces such as warping thin metals, distorting composites and polymers, or pitting more sensitive materials.

Where dry ice blasting has a competitive advantage:

Dry ice is non-abrasive and does not depend on friction-based removal of contaminants from surfaces to achieve optimal cleaning. The three-step dry ice blasting process for contaminant bond breakage (kinetic impact, thermal embrittlement, and rapid gas expansion) is significantly gentler, causing no surface damage to most materials.

5. Sandblasting requires extensive PPE gear to operate safely:

Even the “dustless” variants of sandblasting create airborne particulates during the cleaning process, all of which eventually settle on the surrounding environment and the operator. Extensive PPE precautions must be enacted to avoid irritation in the skin, eyes, face, and lungs of the operator. PPE recommendations that follow OSHA guidelines include the following when sandblasting:

• Type CE NIOSH-certified blasting airline respirator with positive pressure blasting helmet/protective hood that covers the head, neck, and shoulders (satisfies OSHA standard 1910.134)
• Full Tyvek suit or thick coveralls to protect skin from various abrasive particles and dust
• Heavy-duty leather gloves that cover hands and forearms to protect skin
• High-quality ear protection to mitigate the high-decibel noise created by sandblasting equipment
• Work boots that do not allow dust exposure

Where dry ice blasting has a competitive advantage:

Since CO₂ is neither toxic nor an irritant, exposure is mitigated through proper ventilation of the work area. Additionally, minimal PPE such as gloves, eye protection, and ear protection are typically all that is needed to operate dry ice blasters.

Photo by Jimmy Nilsson Masth on Unsplash 

6. Individual parts must be removed or disassembled from the larger machine to be cleaned:

Whole industrial machines cannot be cleaned by sandblasting due to its abrasive blasting media and tendency to get into unwanted areas that cause damage or malfunction. Individual parts must be removed to be cleaned. If many parts require cleaning from an individual machine or vehicle, sandblasting can become an extremely time-consuming task. Let’s use a real-world example of stripping paint from a vehicle hood—the sandblasting process would follow these steps:

1. Remove the hood from the vehicle for cleaning
2. Prepare a designated workspace for sandblasting by covering surfaces and objects that need to be protected from the abrasive blasting media
3. Place the hood within the designated workspace
4. The operator must put on the required PPE gear with respirator
5. Move the sandblaster into position near the hood
6. Plug the machine into a local power source and turn it on
7. Hook up the compressed air and attach the necessary blasting hoses
8. Insert clean blasting grit into the blaster pot
9. Set blast pressure (so as not to warp the metal) and begin blasting the paint off the hood
10. Clean up the contaminated blasting media from the surrounding area and remove it for proper disposal
11. Reattach the hood to the vehicle and prepare it for repainting (if applicable)

Where dry ice blasting has a competitive advantage:

When you clean with dry ice, equipment and surfaces can remain online, in-place, and at operating temperature during the cleaning process. Often, the only steps required for dry ice blasting are the following:

1. Move the dry ice blaster into position near the surface that needs cleaning
2. Plug the machine into a local power source and turn it on
3. Hook up the compressed air and attach the necessary blasting hoses
4. Insert dry ice pellets into the hopper
5. Dial in necessary settings on the dry ice blaster for optimal cleaning such as pellet size, air pressure, and dry ice consumption rate
6. Attach the right nozzle for the task to the applicator
7. Aim the nozzle at the surface and pull the trigger to begin blasting.

All these steps can be accomplished in under 10 minutes, and the disassembly and prep time required for the sandblasting process is eliminated.

Final Takeaway: Dry Ice Blasting is a Faster, Less Cumbersome Cleaning Method Than Sandblasting

While sandblasting still has its place in industrial cleaning for certain tasks, dry ice blasting is a proven method that provides versatility and fast results in most cleaning scenarios. Extensive preparation and cleanup are not necessary with dry ice cleaning. Dry ice blasting is much quicker in cleaning surfaces and can be used in a wider variety of scenarios. 

Need an effective industrial cleaning tool that limits downtime and doesn’t make a mess? Contact Cold Jet to find the right dry ice blasting solution for you!