Restoration Question

From: Dwight K. Elvey <dwightk.elvey_at_amd.com>
Date: Mon Dec 30 17:22:00 2002

>From: "J.C.Wren" <jcwren_at_jcwren.com>

> I have recently acquired a couple of build PC boards that are not
solder
>masked. There is some oxidation, ranging from minimal to mild (mild being
>the not quite green, but a very hard oxide, as if the tin had reacted with
>something else). Anyone got any good ideas on cleaning these? I'd like
>something non-submersible, since one of the boards contains keyswitches.
>
> I have plenty of experience cleaning unbuilt boards. Normally, I'd
just
>hit them with some super fine steel wool, or buff them with 20lb paper.
And
>I've repaired boards, but usually to get them working, not to restore their
>aesthetic appeal.
>
> I've considered using a baking soda solution and a stiff bristle
brush.
>This should neutralize any corrisive elements, and the baking soda might be
>abrasive enough to remove the oxides without damaging the board. It would
>wash off easily enough with water, and I could protect the switches during
>that process.

Hi
 Baking soda assumes that it is acid that caused the corrosion.
If it was caused by leakage from NiCads, you'll need to use
something like vinegar to neutralize it.
 You might try getting a fiber glass brush from a welding shop.
These are sometimes used to clean aluminum.
 Sometimes it isn't the copper that is oxidized. They put a
layer of nickel between the copper and solder on most PC boards.
It may be nickel oxides ( bluish green ).
 If there is any kind of salts ( neutral ) you'll still have
electrolytic corrosion. You need to make sure that it is well
cleaned before you are done, regardless of what you use.
Dwight

>
> Anyone got any ideas or standard procedures for this kind of thing?
>
> --JOhn
>
>
>
Received on Mon Dec 30 2002 - 17:22:00 GMT