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How to "quantify" coverage of clear chromate on aluminum

I am the Quality Control Manager at a sheet metal fabrication/welding house. The Quality Engineer from one of my customers is asking me to have my plating vendor "quantify" the coverage of clear chromate on his aluminum parts per ASTM B449, class 3. According to what I've seen, the coating mass per unit area for this class is <0.1 gram/meter squared. How can this be quantified? My plater states that he can "verify" coverage through the use of a spot test, but he is even stumped by how to "quantify" per the spec.

Craig Poirier
sheet metal fabrication/welding - Newburyport, Massachusetts
2004

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2004

For the analyitcal procedure contact Macdermid service New Hudson Mi Or phone Henkel corp. both supply proprietary chromate conversions coating chemicals. they use mg/sq.ft. but it can be converted to gm/sq M.

Don Baudrand
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [on Amazon or AbeBooks affil links]
           and "Plating ABS Plastics" [on Amazon or eBay or AbeBooks affil links])

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Ask the "quality engineer" which method he prefers...

Jeffrey Holmes, CEF
Spartanburg, South Carolina
2004

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