‘Soda Blasting’ is used to describe the process of using sodium bicarbonate (baking soda) as a blasting medium. Baking soda is a soft abrasive which allows it to remove unwanted layers of grime, paint, grease, soot, etc. We consider Baking soda as a cleaner rather than a blasting media, we just use blasting machinery to apply it to the item being cleaned. There are many ways this can be achieved and we will try to explain the basics.
What is Bi-Carb Soda?
Bi-carb soda is a white crystalline solid most commonly used in cooking as a leavening (raising) agent. Classified as a salt with a chemical formula of NaHCO₃ it easily reacts with acids helping to reduce the bitter flavour of acidic foods.
Uses of Sodium Bicarbonate
Commonly used in the home for cleaning chores and the ever-popular science experiment of baking soda and vinegar to produce fizzy bubbles. The full list of uses includes but is not limited to the following:
- Leavening
- Baking powder
- Pyrotechnics
- Mild disinfectant
- Fire extinguisher
- Neutralization of acids
- Sports Supplement
- Agriculture
- Medical uses and health
- Personal hygiene
- Veterinary uses
- Cleaning agent
- Odor control
- Hydrogen gas production
Is bi-carb soda the same as baking soda?
Yes, bi-carb soda and baking soda are the same thing. It holds different names in different parts of the world. In the United States, it’s frequently referred to as baking soda, whereas in Australia, the United Kingdom, and Ireland, the term bicarbonate of soda is more common. Additionally, abbreviated forms such as sodium bicarb, bicarb soda, bicarbonate, and bicarb are widely recognized.
Is Baking Powder the same as Bi-carb/baking soda?
Baking powder is NOT the same as Bicarb. Baking powder contains around 30% of Bi-Carb Soda and various acidic ingredients which are activated by the addition of water, without the need for additional acids in the cooking medium. Baking soda is alkaline so the acid used in baking powder avoids a metallic taste when the chemical change during baking creates sodium carbonate.
Baking Soda for abrasive blasting
The bi-carb of soda we use in abrasive blasting is different.
As a salt, in water, it separates into sodium ions and bicarbonate ions. Bi-carb used in wet abrasive blasting has been treated to slow down the rate at which it dissolves.
Baking soda in water is alkaline with a pH of about 8.3.
Brief Soda Blasting History
In the mid-’80s, as part of the 100th-anniversary celebrations, the Statue Of Liberty was given a full makeover and repair. The internal steel structure and copper surfaces were all cleaned and re-coated.
Many different methods were used to achieve the required removal of old coatings on the steel structure. However, when it came to the copper skin, only a delicate touch would be suitable. With many experts involved in the project, it was identified that using bicarbonate of soda through an abrasive blaster would perform best.
A commercial-grade bicarbonate of soda (baking soda) was manufactured and donated by Arm & Hammer. It was abrasive enough to remove the green oxidisation but, gentle enough to complete all the copper surfaces.
With such a high-priority job using this ‘new’ media, it quickly became popular for many other applications.
Soda Blasting: The Pros and Cons
Embracing the Good: A World of Possibilities
Many new applications for soda blasting were quickly found. Where low to minimal impact on the substrate was required, soda seemed to be the way. Cleaning glass, stainless steel, and aluminium were suddenly possible without making the slightest mark on the surface. The use of basic abrasive blasting units was commonplace but the flow characteristics of soda and sand are quite different. Vibrating bearings and other mechanical means were all tried with varying amounts of success. Technology and design quickly advanced to more efficient machines of today.
Baking soda has less impact on the environment when compared to chemical treatments. Bicarbonate Soda is a food-grade cleaner that is suitable for most food preparation equipment. Soda blasting is a common cleaning practice for commercial kitchens, production equipment, mixing vats and ovens. Soda blasting is also, less aggressive than other blasting media. This is great for engine parts, brass and surfaces that shouldn’t be pitted by the blast media in any way.
The Downsides: Challenges to Overcome
Even as a “safe” blasting medium, bi-carb soda does have drawbacks. As it turns out, bicarbonate of soda makes for an effective weed killer. Its bicarbonate ions, found in all living systems, readily convert to CO2 and water. While sodium is crucial for plant growth in small quantities, excess sodium can be toxic. Plants that come into contact with excessive sodium turn yellow and may take weeks or months to recover. Soda blasting must be contained so landscapes and gardens are not affected. Garden Myths has a good article explaining more about Baking Soda in the garden.
Even when used in a closed system like a booth or cabinet, Soda blasting is a single-use item. Because the soda particles shatter into small dust particles they cannot be used again and mainly for this reason, Soda Blasting is more expensive than regular media blasting. It should only be used for high-end jobs where ‘cleaning’ is required over ‘surface preparation
Something obvious to anyone dealing with soda blasting… the dust! Even with wet abrasive blasting, there’s a noticeable drift of bi-carb soda from the blasting area. When soda is blasted onto a surface, the particles break into much smaller pieces. This process is what cleans the surface but also produces a large amount of particles that will need some containment.
The Verdict: A Balanced Perspective
It certainly has a place as a beneficial medium for certain jobs and applications. Many people are either for or against Soda Blasting. Here at MP BLAST, we recognise that there is a place for soda blasting. If the application calls for soda blasting, use it!