[TriEmbed] soldering oxidized pins - QFN part

[Van Watts]

I would also pursue the solvent/acid approach.  My understanding has always been that this is part of the purpose of Flux. Wikipedia seems to echo this:

"The role of a flux in joining processes is typically dual: dissolving of the oxides on the metal surface, which facilitates wetting by molten metal, and acting as an oxygen barrier by coating the hot surface, preventing its oxidation. In some applications molten flux also serves as a heat transfer medium, facilitating heating of the joint by the soldering tool or molten solder."

I have no experience with aggressive corrosion/oxidation however, so I would be interested in hearing if flux is indeed useful in such cases. 

Regards,
Van

Sent from my iPhone 6

On Jan 27, 2016, at 2:56 PM, Brian via TriEmbed <triembed at triembed.org> wrote:

That's what drove my H2SO4 (battery acid) suggestion.  QFP leads are probably tin-plated copper, so the most likely oxide is tin oxide. Acetic acid (vinegar) and salt is good versus copper oxide, but not as effective versus tin oxide.

-B

> On 1/27/2016 1:30 PM, Shane Trent via TriEmbed wrote:
> What about a week acid (vinegar)? Here is an Instructable using salt and
> vinegar to clean copper wire. Or you could use a more aggressive flux.
> 
> http://www.instructables.com/id/How-to-perfectly-clean-wires-in-minutes/
> 
> Shane

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