Frequently asked questions about Dry Ice, Dry Ice Production and Dry Ice Blasting.
1What is dry ice?
Dry Ice is the solid form of Carbon Dioxide (CO2). CO2 is a colorless, tasteless, odorless gas found naturally in our atmosphere.
2What is dry ice blasting?
Dry ice blasting is similar to sand blasting, bead blasting, or soda blasting where a media is accelerated in a pressurized air stream (or other inert gas) to impact and clean a surface.
3How do I store dry ice?
Dry Ice should be stored in an insulated container. The thicker the insulation, the slower it will sublimate. Depending on the climate and thickness of your container, typical dry ice sublimation is approximately 2% to 10% per day.
4Why would I use dry ice instead of a traditional blast media?
Most other blast media leave secondary waste behind. Dry ice sublimates (vaporizes) upon impact with the surface. All that remains is the contaminant you are removing, displaced from the substrate. Also, since dry ice vaporizes on impact, the process can be used to clean complicated cavities where typical grit blast media will become trapped.
5How does the process work?
Unlike other blast media, dry ice has a temperature of -109°F (-78.3°C). Because of the temperature difference between the dry ice particles and the surface being treated, thermal shock occurs, breaking the bond between two dissimilar materials.
6What happens to the contaminate?
Contaminants can be dry, wet, hard or soft. Dry contaminants will break up into small chips and can be swept up or vacuumed. If the particles are large enough, they do not become airborne. If the contaminant is wet such as grease or oil, the Cold Jet stream will move or push the liquid away much like a high pressure water stream would, except that the surface where the contaminant was will be dry and clean. To prevent re-deposition, the operator should work in a methodical way, from the top down.
7Does the contaminant or dry ice pellets ricochet?
Upon impact, dry ice pellets sublimate to a gaseous state and therefore dry ice particles typically do not ricochet. The removed contaminant is usually washed away by the blast jet stream and does not come directly back into the blast gun vicinity; however, safety glasses must be worn at all times during the operation of the machine.
8Will dry ice blasting damage the substrate?
The Cold Jet dry ice blasting process will not damage the substrate. The size of the dry ice pellets and their velocity can be optimized to remove the contaminant while remaining non-abrasive to the substrate. The Cold Jet process can clean delicate chrome or nickel plated tools, soft aluminum or brass alloys, wire insulation and even circuit boards – all without causing damage.
9Can you use Cold Jet® dry ice blasting to clean hot tools online?
Yes. In fact, dry ice blasting cleans faster when the substrate is hot.
10Does dry ice blasting cool the substrate?
Yes, but not dramatically. The amount of cooling depends on the substrate material, the dwell time of the dry ice blast stream, and the dry ice usage. For example, a 30 inch (76.2 cm) by 30 inch (76.2 cm) rubber mold may have an initial temperature of 325°F (162.8°C). After the tool has been blasted clean (approximately 12 minutes), the temperature of the mold is about 300°F (148.9°C).
11Will the temperature reduction damage the hot mold?
Generally, no. The temperature change of the surface being cleaned is small and the corresponding tensile stress will be well below the point of what most molds will encounter during normal heat treatment.
12Will the process create condensation?
Condensation occurs when the temperature of the substrate falls below the dew point. The dew point varies with climate and the daily weather patterns. When cleaning hot substrates, condensation will rarely occur because the temperature of the surface will stay above the dew point. If condensation does form, you can control it by using heaters, heat lamps or blow off devices.
13What equipment will I need for my cleaning application?
The dry ice blast system will come complete with blast and air hose, applicator and nozzle best suited for your application and a training CD to reference and train staff. The only other items needed to operate your Cold Jet Dry Ice blast system are plant air, electric power from a common wall receptacle, and dry ice pellets or block (depending on the system).
14How much air will I need?
A typical Cold Jet dry ice blast system operates at 80 psi (5.5 bar) with 150 scfm (4.25 m3/min), however your needs wil depend on your application. Low flow nozzles are available, which require only 50 scfm (1.42 m3/min) at 80 psi (5.5 bar).
15Where can I find dry ice pellets, nuggets and/or block?
Dry ice pellets, nuggets and/or block are available worldwide. In the United States, call +1-800-SEND-ICE (+1-800-736-3423) or +1-513-831-3211, and in Europe call +32 (0)2 467 4101 for the location nearest you.
16How portable are the dry ice blasting machines?
One pearson can easily roll any of the machines around the plant floor without any special equipment.
17Is it safe to use dry ice blasting outside?
Yes. CO2 dry ice is safe to use in outdoor blasting applications. In fact, many organizations have given Cold Jet® their stamp of approval for the use of dry ice in outdoor blasting applications, including the California Environmental Protection Agency.
18How much dry ice should I expect to use?
The amount of dry ice needed to clean effectively can vary dramatically with each dry ice blast system and cleaning application. The average ice consumption for Cold Jet dry ice blast equipment is approximately 2 1/2 lbs (1.1 kg) per minute.
19Will I need an after-cooler?
fter-cooler may be useful if you are a Contract Cleaner or Restoration Contractor using a portable diesel compressor as your air source. An after-cooler provides assurance that the Cold Jet dry ice blaster will not blast any moisture from the diesel compressor being used. This is primarily dependent on humidity levels. Your sales representative will be able to assess your needs and recommend the proper system configuration to ensure your productivity is maximized with moisture-free delivery of dry ice from your Cold Jet dry ice blast system.
20How much maintenance is required to maintain my system?
Very little. Cold Jet dry ice blast systems are designed to provide years of trouble-free use with a minimum amount of maintenance. Each system comes with an operator manual that outlines recommended routine maintenance - periodically checking filters and examining hoses for cracks are two examples.
21Is it okay to blast in an enclosed area?
Yes, with proper ventilation. Because CO2 is 40% heavier than air, placement of exhaust vents at or near ground level is recommended when blasting in an enclosed area. In an open environment, existing ventilation is sufficient to prevent undue CO2 buildup. Even though CO2 is non-poisonous, it does displace oxygen in the atmosphere.
22What are the primary safety issues when dry ice blasting?
One safety issue is to protect workers from moving parts. Cold Jet equipment is designed so that workers do not have access to moving parts without shutting down the system. Another concern is the temperature of the dry ice. At -109°F (-78.3°C), we recommend wearing gloves when coming in contact with the dry ice. Eye and ear protection should be worn at all times.
23How loud is the system?
Noise is a function of air volume and air velocity. Within the nozzle, the stationary air is sheared by the high velocity air, causing turbulence and creating noise. With appropriate hearing protection, an operator can safely operate the system all day.
24What is the difference between a single-hose system and a dual-hose system?
With a dual-hose blast system, the dry ice travels in one hose and the high pressure air in another. They are not mixed until just before they exit the nozzle. Single-hose blast systems mix the high pressure air and the dry ice from the time it leaves the machine. Single-hose systems can at times be the better choice when needing a more aggressive clean.
25How do I know if I want pellets or shaved block particle blasting systems?
The smaller shaved particles have an advantage when removing most paints or when cleaning equipment with intricate geometries or tiny openings such as microvents or screens. Pellets are more suitable when removing thick contaminants - as the larger mass behind each individual pellet is better able to penetrate the contaminant and create the shockwave necessary to disbond it.