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February 2002

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Tue, 5 Feb 2002 22:32:31 EST
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Hi Seth!

The "exposed copper monster" raises it's head again...I'm just asking, is
exposed copper REALLY a bad thing? I've seen many differing opinions...if
it's such a bad thing, how do OSP coated boards survive? How did the Statue
of Liberty survive for 100-years in the elements, acid rain on the east
coast, etc..or the uninsulated telegraph wires strung over the USA?

Just asking; is exposed copper (other than solderable surfaces that were
intended to be plated and didn't because of dewetting or some other reason) a
REAL problem?

I might think that if the assembly were subjected to a corrosive enviroment
it could be a problem, but then the assembly should be protected with a
conformal coating because the tin/lead plating is going to suffer as well.

From my understanding about copper oxidation, copper will oxidise to a
certain point and then stop, the oxidation actually prevents further
oxidation. That's the desirable green patina that one sees on old sculptures.
Am I wrong about this?

-Steve Gregory-


> It's too easy for a small scratch to expose
> copper and that's not a good thing.  My two cents worth, anyway.
>
> Regards,
>
> Seth Goodman
> Goodman Associates, LLC
> tel 608.833.9933
> fax 608.833.9966
>



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