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Is zinc plating too sensitive to packaging atmosphere?

October 29, 2010

HI

This is the question that comes to my mind without getting a correct solution;

Is plating is too sensitive to atmosphere?

Plating is done all over the world, the temperature condition won't be same, it may be cold, hot, breeze or full time raining. These are all open atmosphere - we have done an environmental testing for Zinc plating we got a good result for more than 3 years we don't find any change we are very happy to say.

But in a closed atmosphere the 13 micron thickness Alkaline zinc- trivalent passivated component even though kept in volatile (VOC) covered packed with cardboard box get black patch/spot with in 1 and half month ...what might me the reason?

where our inspector are strictly to wear cotton gloves during inspection/handling and packing.

your valuable solution will really help me to come out of this issue

Deepan M
plater - Chennai, Tamilnadu, India

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Hi, Deepan. My guess: sulfides or other problems in the cardboard packaging.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 1, 2010

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Sir,

How can we find sulfide content in a cardboard box; whereas we pack our various components only through cardboard box where we didn't find any change in plating/black spot problem till now.

But one thing this is the only big component which is 3000 mmL & 50 mm B, Component which is 'S' Shaped. Where we pack 250 Nos in one Box.

Pls help as to find the major root cause & how to rectify our issue.

Deepan M
plater - Chennai, Tamilnadu, India
November 4, 2010

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Dear Mr Deepan,

If this problem is peculiar to the months between June and October - you can blame it on the humidity in Chennai in these months.

If it's in a non monsoon month with normal humidity around 50% then it may be the porosity in the sheet metal particularly the Hot rolled grades.

Both of the above apply only assuming that you are doing everything right in your process in the first place.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

November 24, 2010