Both soda blasting and sand blasting are widely used in various industries for their speed and precision in smoothing, cleaning, or removing surface finishes. Both consist of blasting a surface with “media” to remove paint, dirt, or other undesirable surface contaminants. The list below seeks to clarify the differences between the two.
Soda Blasting Pros:
Eco-friendly – The media used when soda blasting is bi-carbonate of soda. Although it is a larger particle of soda than that used in the food industry, it is the same purity.
Nontoxic – Sodium bicarbonate (NaHCO3), is a major element in the human body and is not toxic by ingestion, inhalation, or dermal contact. In fact, soda blasting is endorsed by the U.S. Department of Agriculture (USDA) and the FOOD & Drug Administration (FDA) and is Kosher approved.
Non-abrasive – Bicarbonate of soda is very soft, only 2.4 on the Mohs scale of hardness. With soda blasting, the soda crystals explode outward when it comes in contact with any substrate, and removes the surface contaminant with this action, without damaging the substrate.
Rust inhibitor – The powdery film remaining after soda blasting inhibits ‘flash rust’ from forming, eliminating the need for an immediate application of coating to cover the exposed metal.
Does not produce heat – Soda blasting does not generate any heat on impact, so it will not distort or warp the object being treated.
Water-soluble – Although, there isn’t usually any soda to collect after blasting, there may be a powdery film covering the object that was blasted. A quick rinse will eliminate it.
Does not activate metal – Activated metal requires immediate coating to prevent rusting. Soda blasting does not break down the surface tension because it does not generate any heat.
Does not spark – The non-flammable properties of sodium bicarbonate eliminates the threat of electrical sparks, however, some static electricity is unavoidable when propelling media at high pressure, so it is best to properly ground a metal object prior to soda blasting.
Breaks down hydrocarbons – Soda blasting is an effective solution against petroleum and hydrocarbon buildup on engines, encapsulating it. After blasting with soda the contaminant is easily rinsed away.
Eliminates odors – Soda is slightly alkaline and neutralizes acid-based odors in water and absorbs odors from the air. It eliminates any odors from fire and is the only blasting media with this property.
De-coats and cleans in one step – Often a substrate coating is covered with a contaminant which needs to be removed before being blasted off, so it is not driven into the surface of the substrate. Soda blasting has the ability to clean off the coating prior to removing it.
Minimal clean-up – As the soda particles explode upon impact, the clean-up only includes the contaminant(s) removed.
Sand Blasting Pros:
Ability to profile a surface – Sometimes in the manufacture of a metal object, the surface needs to be profiled so the finished coating will adhere. Sand blasting creates this surface profile.
Aggressive abrasion action- allows for quick removal of surface contaminants.
Soda Blasting Cons:
Alkaline properties will harm plants – Soda is slightly alkaline and will harm nearby plants and vegetation if any dust is not rinsed off properly after a treatment.
May collect in crevices – Special care needs to be taken to rinse out corners and crevices of items treated before applying finish.
Requires tenting for dust control – In some situations when it is not suitable, or practical, to include water when soda blasting.
Will not create a surface profile – Sometimes in the manufacture of a metal object, the surface needs to be profiled so the finished coating will adhere. Soda blasting does not create a surface profile because of its nonabrasive hardness (2.4 on the Mohs scale).
Limited storage time – Extra precaution needs to be taken when storing the soda blasting media because it readily absorbs moisture and clumps together. When this happens it will not flow through the blasting pot and cannot be used.
Sand Blasting Cons:
Abrasive – Sand blasting removes surface contaminants by wearing it away. The substrate is easily damaged if sufficient care is not used.
Contains Silica – Sand contains silica. The U.S. National Institute for Occupational Safety and Health has determined continued exposure to silica is a serious health hazard, leading to the often fatal lung disease, silicosis.
Generates heat and sparks – The action of propelling the highly abrasive sand particles against a substrate generates heat, sparking, and static electricity, requiring extra safety precautions to be taken.
Activates metal – Heat generated by sand blasting activates iron, and iron compounds, causing immediate oxidation (rust).
Considerable clean-up effort – Depending on the size of the job, there is all the sand that was used, as well as, the contaminant that was removed and some of the substrate. And if it was a wet blast everything is very soggy.
Illegal in some areas – Because of the health hazards and toxic waste, make sure you are not doing something illegal before you plan to sand blast.
This information is the result of extensive research and is sourced from several experts in the industry, environmental specialists, and relevant government departments. The findings suggest soda blasting and sand blasting have different applications and are used for different results. What outcome you want to achieve, or what purpose you need to accomplish, will determine whether you use soda or sand.