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Bead Blasting vs Citric Acid Passivation [Massachusetts] 

July 29, 2008

Which process would be better for surgical instruments - bead blasting or citric acid passivation. We are under the impression that bead blasting is harmful to the instrument and that treating it with citric acid is better to remove the staining and to reapply the passivation. We believe that bead blasting only opens up the instruments pores to more staining or rusting. Does anybody have any information to verify or nullify this idea?

Bruce Cunningham
owner of instrument repair business - Wareham, MA, USA

Bruce,
You're not really comparing equivalent processes. Bead blasting is usually done to smooth down a very rough surface or to clean off scale. A passivation bath removes iron and improves the protective chrome oxide layer.

If your application is cleaning and repairing surgical instruments, I see no reason why you would want to bead blast and every reason you would want to passivate.

If there is the occasional stain that cannot be removed by a citric bath, the best course would be a brief pickling in a harsher acid (phosphoric or nitric if necessary), rather than a mechanical process like blasting or grinding.

Ray Kremer Stellar Solutions, Inc. Algonquin, IL, USA