Editing Soda blasting

Soda blasting is the use of sodium bicarbonate ("baking soda") or sodium bicarbonate-based materials as blast media for paint stripping and rust removal. Soda blasting is controversial in hotrodding because substrates that have been soda blasted often display poor adhesion characteristics as a result of blasting residue left on the substrate. In addition, even when the residue is completely removed, soda blasting may offer no savings over conventional media blasting, because of the extra steps required to remove the residue. Nevertheless, in the right conditions, soda is a useful blasting medium. ==Soda blasting history== Soda blasting was originally used as a method of stripping/cleaning industrial machinery. It was developed in the 1980's, and was most notably used to restore the Statue of Liberty. Soda blasting crossed over into the automotive restoration field as somewhat of a miracle process, a misconception that had to be debunked. Although soda has its valid uses as a blast medium, it also has its own set of complexities and nuances that must be taken into consideration. ==Soda blasting procedure== Soda blasting is done with a high volume, low pressure wet or dry blasting machine. Soda cleans surfaces not by abrasion, like conventional blasting media, but by the energy released by the explosion that occurs when the soda particles contact the substrate. ===Soda blasting medium=== The sodium bicarbonate used as a blasting medium is chemically identical to "baking soda"; however, the blast medium typically uses larger particles. Some soda blasting media also include additives to prevent caking or help flow, such as tricalcium phosphate or calcium carbonate. ====Examples of soda blasting medium==== *[http://www.sodaworks.com/pages/products/NatruimSodaBlast.php Natrium] -- pure sodium bicarbonate, typical particle size of 290 microns. *[http://www.sodablastsystems.com/ SodaClean Maintenance Plus] -- sodium bicarbonate with tricalcium phosphate and TFF: "treated free flowing additive". ===Soda blasting residue removal=== Removal of residue is crucial to the soda blasting procedure. [http://www.holdtight.com/index.htm Holdtight 102] has been recommended for use in cleaning soda-blasted surfaces prior to application of primer. [http://www.nutechsodablasting.com/content/view/14/12/ More details on Holdtight 102]. Correct soda blasting procedure may involve the following steps after blasting: *Cleaning with soap and water (or vinegar/water solution). *Blowing dry. *Sanding with 180 grit sandpaper. *Degreasing. *Epoxying. ===Resources=== *[http://www.fordmuscle.com/forums/body-paint-articles/485680-soda-blasting-budget.html Soda blasting on a budget] ==Reasons in favor of using soda blasting== *Environmental friendliness. *Non-destructive, and won't warp panels. *Doesn't harm glass, chrome, or rubber (but may harm certain types of plastic trim). *Does not cause heat buildup or sparks. *Does not abrade substrate. *It's water-soluble, and can typically be washed down a conventional drain. *The soda blasting residue can be temporarily left on the substrate, as a rust inhibiting protective coating. *Sodium bicarbonate has a well-known chemistry, and is widely considered safe to use. *You can soda blast lightly to leave the body filler intact, and then go over it again to remove all filler. *No pre-cleaning required (Prior to blasting, traditional blasting media may require the surface to be thoroughly cleaned to remove salt, carbon, or grease.) *Allows for easier detection of surface flaws. (Traditional abrasive media may peen cracks closed, or fill them with abrasive, whereas soda cleans out the cracks). For a professional, experienced shop that's well-trained in its use, does all of the finish prep work itself, and has a soda-friendly guarantee from its paint supplier, soda blasting may be a viable choice. ==Reasons against using soda blasting== *Difficulty of residue removal, especially on parts with cracks/crevices, such as door jambs, engine bays, trunks. Residue can also hide in and behind fasteners. *Laborious, time-consuming steps required to prep parts after blasting. *Only removes light flash rust. *Does not leave an anchor pattern. *Voids warranties with many paint manufacturers. *Can't re-use the medium after blasting. Overall, soda blasting is probably not the best choice for the hobbyist or do-it-yourselfer. ==Published professional opinions on soda blasting== *[http://www.southernpolyurethanes.com/tech%20sheets%20new/epOXY%202006.pdf Southern Polyurethanes]: <blockquote> ''"NEVER use SPI Epoxy over a Soda Blasted vehicle, Acid Etch/Wash Primer, Rust Converter or other Metal Treatments. NEVER!"'' </blockquote> This opinion is expanded upon in [http://spi.forumup.org/viewtopic.php?t=156&mforum=spi this discussion in the Southern Polyurethanes forums]. *[http://www.search-autoparts.com/searchautoparts/article/articleDetail.jsp?id=130652 John Hughes, Ford Motor Company refinish technical expert]: <blockquote> ''"We don't recommend sodium bicarbonate, because you can’t clean it out of the pores of the metal well enough."'' </blockquote> ==Related articles== *[[Rust]] *[[Media blasting]] ==References== *http://en.wikipedia.org/wiki/Sodablasting *http://www.hotrodders.com/forum/once-all-wiki-soda-blasting-162700.html *http://www.tristatesodablasting.com/faqs.html *http://www.universalminerals.com/library/soda-blasting-overview.shtml *http://www.balearicsodablasting.com/FAQ.html *http://www.nutechsodablasting.com/content/view/3/7/ *[http://siri.org/msds/f2/bdm/bdmjw.html Sodium bicarbonate MSDS]

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