[TriEmbed] soldering oxidized pins - QFN part

Brian triembed at undecidedgames.net
Wed Jan 27 12:28:51 CST 2016


Honestly IMHO it's hard to imagine anything good coming out of getting 
near a wire brush wheel with a QFP.  At a minimum, it'd probably bend 
the mess out of the pins; at worst it'd tear them right off.  Effective 
brushing really requires bristles that are a significantly small 
percentage of the size of the thing being brushed.  A fiberglass brush 
wheel, if such a thing exists, might be a better option.  Wear a mask.



On 1/27/2016 12:36 PM, Glen Smith via TriEmbed wrote:
> After the pencil eraser my next step (if needed) would be a nylon
> bristle or wire wheel in a Dremel tool. I used mine recently to clean up
> some battery contacts damaged by Alkaleak batteries. A light touch would
> be essential, but I'm betting this would rejuvenate the chips pretty
> quickly, with no need for caustics.
>
> Glen
>
> On Wed, Jan 27, 2016 at 11:49 AM Mauricio Tavares via TriEmbed
> <triembed at triembed.org <mailto:triembed at triembed.org>> wrote:
>
>     On Wed, Jan 27, 2016 at 11:21 AM, Jeffrey Crews via TriEmbed
>     <triembed at triembed.org <mailto:triembed at triembed.org>> wrote:
>      > It might be worth it for someone at Tri or Splat to score some
>     "crocus
>      > cloth." It's like ultra-fine emery (actually red
>     rouge-impregnated stiff
>      > cloth) usually used for polishing fine/soft metals like gold.
>      >
>      > I used to have some and it was awesome because it didn't damage
>     anything or
>      > remove gold or other platings.
>      >
>      > Come to think of it, I'll get some.
>      >
>      > JSC
>      >
>      > On Wed, Jan 27, 2016 at 11:12 AM, Carl Nobile via TriEmbed
>      > <triembed at triembed.org <mailto:triembed at triembed.org>> wrote:
>      >>
>      >> If you have some really fine non-metallized sandpaper you could
>     give the
>      >> part a few twists on the paper first.
>      >>
>      >> ~Carl
>      >>
>      >>
>      >> On Wed, Jan 27, 2016 at 10:57 AM, Alex Davis via TriEmbed
>      >> <triembed at triembed.org <mailto:triembed at triembed.org>> wrote:
>      >>>
>      >>> I have a QFN part which shows signs of oxidation on the pins,
>     and I'm
>      >>> wondering if there's anything I can or should do to clean it up.
>      >>> Unfortunately, it's an old-stock part, so I can't just get a
>     new one.
>      >>>
>      >>> I have some photos here of the part:
>      >>>
>      >>>
>     https://hackaday.io/project/9150-68040-upgrade-for-powerbook-520c/log/30827-68040-has-arrived
>      >>>
>      >>> I am hoping there's enough un-oxidized metal on each leg that
>     the solder
>      >>> and flux will wet the legs properly. I'll be point soldering a
>     few pins
>      >>> on each side before drag soldering the rest, so I should be able to
>      >>> evaluate if it's going to work before committing to soldering
>     the whole
>      >>> thing.
>      >>>
>      >>> Alex
>      >>>
>      >>>
>      >>> --
>      >>> "The theater of noise is proof of our potential."
>      >>> |\ |  (¯  \/ |¯\  |V| |\ ¯|¯ |¯) | \/ | | | |¯\ (¯   /¯  /\ |V|
>      >>> |-||_ (_  /\ |_/ @| | |-| |  | \ | /\ |^| | |_/ (_ . \_  \/ | |
>      >>>
>      >>> You won't find me on Facebook.
>      >>>
>      >>> _______________________________________________
>      >>> Triangle, NC Embedded Computing mailing list
>      >>> TriEmbed at triembed.org <mailto:TriEmbed at triembed.org>
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>      >>> TriEmbed web site: http://TriEmbed.org
>      >>
>      >>
>      >>
>      >>
>      >> --
>      >>
>      >>
>     -------------------------------------------------------------------------------
>      >> Carl J. Nobile (Software Engineer)
>      >> carl.nobile at gmail.com <mailto:carl.nobile at gmail.com>
>      >>
>      >>
>     -------------------------------------------------------------------------------
>      >>
>      >> _______________________________________________
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>      >> TriEmbed web site: http://TriEmbed.org
>      >>
>      >
>      >
>      > _______________________________________________
>      > Triangle, NC Embedded Computing mailing list
>      > TriEmbed at triembed.org <mailto:TriEmbed at triembed.org>
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>      > TriEmbed web site: http://TriEmbed.org
>      >
>            How about the eraser on a #2 pencil?
>
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>
>
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