[sdiy] Solder corrosion - what is it?

[Chris Juried]

Have you tried giving the pcb an ultra sonic bath?

Sincerely, 

Chris Juried 
Audio Engineering Society (AES) Member 
InfoComm-Recognized AV Technologist
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  On Fri, Nov 4, 2016 at 6:39 AM, Steve Lenham<steve at bendentech.co.uk> wrote:   On 04/11/2016 09:43, Paul Perry wrote:
> orbit.dtu.dk/files/100370544/Corrosion_in_electronics.pdf
>
> http://www.kester.com/Portals/0/Documents/FAQs/White_Residue.pdf
>
> personally, i thnk that the grunge that develops gradually over years,
> is simply oxidation of the lead, accelerated by the presence of
> hygroscopic salts left after soldering.
> So my guess is basic lead carbonate.
>
> paul perry Melbourne Australia

Hi,

Thanks for the responses so far. In my case, I am positive that it is 
NOT flux residue - not only do I have a reasonable idea of what that 
looks like but it is also evenly distributed over all tinned/soldered 
surfaces including large areas of tinned PCB tracking some distance from 
any joint. It also occurs on the legs of socketed ICs where no flux was 
ever present.

Neither water nor IPA dissolve the corrosion significantly. The only way 
to get back to a shiny tinned surface is with slight abrasion e.g. a 
fibreglass pencil, etc. I don't plan to do that on a widespread scale, 
but I would like to lightly brush off as much as possible for cosmetic 
reasons. Hence my concerns about what might be released into the air 
when I do that.

All further input welcomed!

Cheers,

Steve L.




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