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Zinc Plating Spec for Ocean Voyage

November 13, 2009

I have been having problems with rust on shipments to China. We are using the customers plating spec for the parts and I need to know if this spec is sufficient for the trip on the ocean. The parts are sheet metal that house electronic equipment. The spec is:

Zinc Plate per ASTM B633, .0002 in Min., Type ll Passivation; 96 HR Salt Spray Min. and 5 Milliohms per Square Inch Electrical Resistance Max. All surfaces are considered Significant. Trivalent Chromium Based Bath chemistries Shall be Used Until Exception is Provided.

Appreciate any information you can give me. Or if there is a better spec to use I would appreciate that also.

Richard Webb
Quality Manager - Bloomingdale, Illinois

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0.0002 is not enough thickness to withstand the cold damp humidity and temperature cycles in the cargo compartment of an ocean bound ship. You need at least 0.0003 AFTER a high quality chromate is applied, and be aware that the chromate application, try or hex,removes some thickness.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

November 16, 2009

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Thanks Robert I appreciate you taking the time to answer this question.

Dick Webb

Richard Webb
- Bloomingdale, Illinois, USA
November 18, 2009