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Simple insitu test for galvanizing adhesion?

January 19, 2011

Sir

I am taking care of Galvanised steel customer complaints. The customers asked for a simple (comparitive test result) for verifying the Zinc Adhesion to the Base steel.

Also it would be helpful if you can say the test, which can prove the paint peel off problem source. Weak bond between steel and Zinc and / or between Zn and paint.

Requesting you to suggest simple tests for evaluation corrosion life of galvanised plain steel.

Sunny MR
Customer Account Manager - INDIA

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January 19, 2011

Hi, Sunny.

I think that you may be asking for answers to questions before actually understanding the questions :-) Because the second that you see the failed component you will instantly know whether the problem is adhesion failure between the steel and the zinc or between the zinc and the paint -- is the zinc stuck to the paint chips and the steel is bare, or are the paint chips simply paint chips and the zinc is still on the steel?

Unfortunately, I don't think there are any accelerated corrosion tests that will predict the corrosion life of galvanized steel, but the coating has already failed before the test begins if it is not attached to the substrate :-)

What thickness specification are you galvanizing to? Good luck.

Regards,

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

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January 20, 2011

Dear Sir,

there's a calculator on GalvInfo website which can predict the lifetime of a galvanized structure. Hope it helps.

Regards,

CS Leong
- Selangor, Malaysia