Abrasive blasting has been in use for over 100 years, beginning with the use of silica sand as a blast media (hence the term “sandblasting”) However since the increased awareness of the dangers of Silicosis, several modern alternative media have been in use.
The most common alternate blasting media are Aluminum Oxide, Silicon Carbide, Glass Bead, Coal Slag, aluminum or steel pellets. They’re generally used for paint and coating removal, and in some cases rust removal. All of these media are grains of hard, sharp material which, when propelled at high velocity with blasting equipment, can generate a great deal of surface heat resulting in warped panels and etched surfaces. Traditional abrasive blasting remains the best choice for stripping and removing rust from castings or heavy steel parts, but now there are better ways to strip paint from auto body sheet metal and fiberglass.
There are less-aggressive media, including Poly, Walnut Shell, Corn Husk, and others, available for the purpose of stripping paint from auto bodies. However they can require a great deal of clean-up when the job is done, and leave residual particles in the seams and crevices of the car body that are hard to remove.
Bicarbonate of Soda, (commonly known as “Soda Blasting”) is rapidly increasing in popularity. The technology is fairly recent, having been developed in the mid-80s primarily for the purpose of cleaning the Statue of Liberty, a delicate task that required performance without damage.
Fast-forward some 20 years, and we have equipment that’s easily available to the hobbyist who wishes to strip paint from his pride and joy without inflicting damage. In fact, a car can be stripped of its paint without the need for time-consuming masking, actually leaving all trim, rubber and glass IN PLACE, with no harm coming to those components! Additionally, no panel-warping heat is generated, so the surface is left smooth and texture-free even on aluminum and fiberglass! This is because the soda particles completely shatter into a dust after striking and removing the paint, inflicting no harm to the base metal or fiberglass. We recently stripped the paint on a vintage car using a soda blaster and discovered original factory sanding marks on the fender! They were left intact but the paint was gone!
The soda leaves a light, dusty protective film on panels, helping to prevent surface rust for up to several months. This is simply rinsed away with water prior to painting, as you rinse out seams and crevices to remove any stray dust particles. Perhaps the best feature of soda is the fact that it is completely inert and water soluble, saving a great deal of clean-up time when the job is done. (Of course the proper steps should be taken to recover removed paint particles before getting out the hose and washing the dust away.)
One additional use of Soda as a blasting media is to clean and degrease complex mechanical assemblies, such as transmissions or rear axles, with no harm to internal moving parts. Many folks also use it to clean under-hood areas, without removing or harming components or wiring.
