Water-soluble ionic contamination, mainly chlorides from sea air and road salt, that lodges in pits and the blast profile even after blasting. Under a coating it pulls water through by osmosis, forming blisters and restarting corrosion. Inspectors extract it with a Bresle patch or sleeve and measure conductivity or chloride level; many immersion specs cap chlorides at a few micrograms per square centimetre and require washing until the surface passes.
Bresle came back 12 micrograms, spec is 3, wash it with salt remover and retest the soluble salts before we blast.
Blasting alone often drives salts deeper into the pits. Wash first, blast, then test, or the blisters show up a year later.
Also heard as
- chlorides
- salt contamination
- Bresle test
Related terms
Flash rust
Thin, quick layer of rust that forms on freshly blasted or water-washed steel within minutes to hours.
Near-white blast
Blast grade allowing light shadows or stains on no more than 5 percent of the surface, the usual immersion standard.
White metal blast
Top abrasive blast cleaning grade: bare, uniform steel with no visible residue, rust or staining.
Holiday
Pinhole, void or bare spot in a coating that leaves the metal underneath exposed.