Metal finishing Q&As since 1989

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Holidays in electrophoresis coating

We have a product with a Electrophoresis coated part,produced for us in ,where else,China.
samples we got seemed good.
we did comparison testing in a salt spray test bench , against nickel coatings and the "black paint " came out better then the nickel coating with which we had problems.
after switching to this "new" product we received a shipment with the new product only to find (visual inspection)that ~80% of the coated parts show small defects ( not completely covered part,from little pin holes to bigger "scratches").
question. is there anyway to test this besides visual? some kinda holiday test?

Brouwer Jouke
practical engineer ,valve producer - Israel
2007

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I am not sure that I understand the question, Brouwer, but running these parts through the salt spray test will probably produce a very high failure rate. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

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2007

Thanks Mr Mooney

I'll rephrase the question.
how do you test an Electrophoresis coated part for proper coverage.
we find small pinholes in the coating with visual inspection .

Brouwer Jouke
valve manufacturer - Israel

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I am sorry if my original response was hard to understand, Brouwer.

What I am saying is that you were offered parts which passed a salt spray test. You used that passing grade to decide that the sample parts were suitable for your needs.

You now how received a shipment which appears to have holidays, so you doubt that they are suitable. The way to check whether they are non-functional is by performing a salt spray test on some samples from this second batch. If they don't pass, then they aren't what you ordered (from your viewpoint, of course; this is obviously not a self-evident legal opinion).

It doesn't sound reasonable to me to talk about a brand new type test at this juncture because the samples weren't tested to that standard, and whether they have holidays or not (according to some new test) is largely irrelevant anyway if they are neither cosmetically nor functionally acceptable.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007