Expert Guide to Dry Ice Blasting Nozzle Selection

Step 1: Know the CFM of your compressed air supply

Everything starts with your compressed air supply. Your nozzle selection is limited by how many cubic feet per minute (CFM) your compressor can continuously deliver at your chosen operating pressure.

• The rule: As your operating pressure increases, the volume of air (CFM) pushed through the nozzle also increases. If your nozzle demands more CFM at your target pressure than your compressor can continuously produce, your blasting pressure will drop, killing your cleaning speed and stripping power.

Step 2: Choose your pellet size

Dry ice blasting pellets come in a 3 mm base size, and your choice of nozzle can fracture them into smaller sizes.

• Straight, standard: Basic general-purpose nozzle type, excellent for standard cleaning where full pressure or heavy-duty cleaning is needed.
• Straight, MERN (Multiple Expansion Reflection Nozzle): Full pellet nozzle designed to keep full dry ice pellet integrity throughout the nozzle, making it the most powerful nozzle in the Cold Jet fleet. When you need the most cleaning power, this is the choice.
• Variable nozzles: If your machine or shaver produces variable-sized or pre-fractured particles, or if you use a variable (fragmenting) nozzle, it is engineered to fracture pellets dynamically as they pass through. This turns standard pellets into sharp, angular ice fragments for faster stripping on hard-bonded contaminants.

Step 3: Operating pressure (PSI) relative to your substrate

While Step 1 looks at compressor capacity, your chosen pressure dictates the kinetic energy of the impact on your target surface.

• 5-Series, high PSI (110–150+ PSI): Best for stubborn, baked-on carbon, heavy industrial buildup, or structural steel where you need maximum stripping aggression and speed.
• 3-Series, moderate PSI (60–110 PSI): Ideal for light dust or dirt, general maintenance, sensitive machinery frames, or coatings where you want high removal rates without risking mechanical damage to the substrate.
• 1-Series, low PSI (under 60 PSI): Used for delicate surfaces, thin metals, or soft substrates where speed must be balanced carefully against surface integrity.

Step 4: Select your blast width and pattern

Once you know your air, ice, and pressure, choose the blast pattern width that best matches the surface or area being cleaned.

• 1-inch width (concentrated): Perfect for deep-cleaning tight corners, deep-set weld seams, narrow channels, and localized stubborn spots. Concentrates all kinetic energy into a tight path for maximum cutting power.
• 2-inch width (balanced): A versatile width for general component cleaning, and a good mix for jobs that need both focused and broader blasting in a single project.
• 3-inch width (wide): Excellent for covering flat surfaces, machine frames, and moderate-sized housings efficiently.
• 4-inch width (very wide): Best for light dust and debris work in large areas such as ceilings, walls, and long processing lines.

Step 5: Account for physical clearance and reach (nozzle length)

Standard heavy-duty industrial nozzles are typically 23 inches long, which provides great standoff distance and reach, but tight spaces require shorter configurations. Assess your workspace clearance:

• 7-inch length: Ultra-compact. Perfect for cramped machinery interiors, tight engine bays, electrical cabinets, or deep recesses where a long wand physically cannot fit or swing.
• 10-inch and 12-inch lengths: Short-reach options for restricted access areas that need slightly more hand clearance than a 7-inch model, a comfortable compromise between maneuverability in confined spaces and standard operator reach.
• 23-inch length: Standard length, a good fit for overhead and floor work, with a comfortable distance for keeping debris and rebound away from the operator.

Our recommendations

• For almost all jobs, have at least 100 PSI available. Higher PSI, when not needed, can be regulated down at the compressor, at the machine, or with an outside pressure regulator.
• Having higher pressure available and not needing it is vastly preferable to needing the pressure and not having it. We would go into any job with 200 PSI available and regulate down from there if we could.
• If you don’t need to fracture the pellets, don’t use a variable nozzle. But if you might need it, or have no idea, use a variable nozzle: you can always run it as a straight pass-through and get almost as much power as a straight nozzle.
• Use a 523M1 nozzle if you want or need maximum cleaning power. You must have the CFM for the nozzle, but if it won’t clean with this nozzle, it likely won’t clean with any nozzle.
• Wider nozzles vastly speed up the job, but only if dry ice blasting works on the buildup. Start with a 1" nozzle and move up to the widest nozzle that still cleans effectively. Think ceilings, walls, light dust, grease, oils, and similar buildups.
• Shorter nozzles are generally used only when restrictions and space require them.
• These general rules all have exceptions, but the only firm rule is to bring nozzle options on every job unless the job is a repeat.

Troubleshooting