The Science of Soda
Some of you may remember the commercials for Arm and Hammer toothpaste, where the brilliant white teeth were the result of baking soda magic! Well, we use the same stuff (baking soda, not toothpaste) to blast the clinker from your bits and pieces.
Introducing the star of the show
Sodium Bicarbonate (baking soda) is an unassuming white, odourless crystaline solid with the empirical formula NaHCO3, and a molecular mass of 84g/mol. It is soluble in water and produces an alkaline solution.
Size matters
The first thing to bear in mind is that the particles of baking soda we fire at your work piece are small – 20 to 300 microns (0.02 to 0.3 mm) in size, selectable by the operator. This is crucial, as it determines the amount of kinetic energy released with each impact between the baking soda crystals and your work piece. This level of control means we can be as gentle as we need to be with more fragile items.
The soft option ….
Baking soda isn’t at all hard. In fact it breaks up quite easily. It rates at 2 on the hardness scale where talc power is 1 and diamond is 10. So how can something so soft have such cleaning power? Well, lets see!
The soda blast breakdown
The major difference between soda and sand blasting is the method by which material is removed from the surface. Grit or sand removes material by abrasion, which relies on brute force to knock and cut material off the surface. It is a high energy process, the media breaks and generates more sharp edges to do the dirty deed, and can create so much heat it is dangerous in hazardous environments, sparks are not unusual in grit/sand blasting!!
Glass bead blasting is almost as bad. The beads are hard and initially dent the surface, then they break creating lots of sharp edges, then then cut into the component, they are efficient but leave the potential for great damage, in the innards of your engine for example……….VAPOUR BLASTING IS BEAD BLASTING WITH WATER AND SOMETIMES STEAM, so beware!
Soda blasting, by comparison, uses very small and fragile crystals, so when they hit the surface they break up – releasing tiny amounts of energy into whatever material they strike. The particles are so small that they get into the microscopic pores of any surface, breaking up any coatings allowing them to simply fall away. Because the particles are quite soft, and non abrasive, they will not abrade metal, glass, plastics, rubber and most other surfaces. The images above show the blast media gradually breaking up the surface material into tiny fragments. The final stage, is simply a good wash down with water to remove any loose debris.
Look Ma! No peening!
One of the most valuable aspects of soda blast cleaning is that there is no peening effect. Because the particles break up on impact they don’t hammer the underlying material. You can usually tell if something has been shot/grit blasted, as it’s been hammered smooth. Fine details are lost, and any cracks or fissures may be completely hammered shut!
Soda blasting on the other hand, is much more gentle meaning any fine detail, or cracks/fissures in the base object are perfectly preserved, and easier to spot afterwards – most helpful in avoiding costly problems later on – especially where engine components are concerned!
Health & Safety
Because baking soda is non toxic, and turns slightly alkaline when dissolved in water (not acidic), there are few restrictions on the use of our system. Operators need only wear basic protection in the open air. The blasting media can be washed away or vacuumed away when the cleaning is done. However, if the material being removed is toxic then suitable disposal is still required.
