Hi Steve - that is an awesome example of how important our material and
process choices can lead to problems when we "select poorly'! And having
the braided cable instead of solid wire aggravated the situation even
further. Great pictures and background detail - I am adding this to my case
files that we use to educate our new engineers! TechNet is awesome, thanks
for sharing such a great detailed example.

Dave

On Fri, Nov 3, 2017 at 11:30 AM, Steve Gregory <[log in to unmask]> wrote:

> Hi Ed and Dave,
>
> I ran into a similar issue back when I was in Tulsa. We were building
> cabinets that had wire harnesses using braided shield wire that the shields
> were silver plated copper. At the time we were using a water soluble no
> clean (which we found out later that you really shouldn't use it as a no
> clean). We built up a bunch of cabinets and had a rather rainy spring which
> caused the humidity to stay high for several weeks. Eventually we started
> seeing this on the braided shields:
>
> http://stevezeva.homestead.com/files/Green_Junk_1.jpg
> http://stevezeva.homestead.com/files/Green_Junk_2.jpg
> http://stevezeva.homestead.com/files/Green_Junk_3.jpg
> http://stevezeva.homestead.com/files/Green_Junk_Close.jpg
>
> We switched over to Kester 951 which the datasheet says that it has a
> "corrosion inhibitor" in the flux, and the green junk went away. Kester
> also put out this paper on green corrosion, or Copper Abietate. Google:
> Green Corrosion Kester.
>
> Steve
>
> On Fri, Nov 3, 2017 at 10:11 AM, David Hillman <david.hillman@
> rockwellcollins.com> wrote:
>
>> Hi Ed - based on the details you provided, here is what I believe is
>> happening - Many of the OA type fluxes contain a significant chlorine
>> content and also consider you have a potential fluorine contribution from
>> the flux interacting with the PTFE insulation. Copper loves to react with
>> both Cl and F with the reaction producing a corrosion product that has a
>> characteristic blue/green optical appearance. The corrosion product can be
>> identified by its unique crystal structure using XRD techniques. It
>> appears
>> you are dealing with a case of poor cleaning as there is flux being
>> trapped
>> under the insulation and it is causing a corrosion reaction. One method of
>> avoiding this issue is to carefully apply the flux to the stripped wire in
>> such a manner as the flux does not contact the wired/non-stripped
>> insulation interface. The best way to clean this is to not allow it to
>> happen during the initial processing - trying to get that interface clean
>> is difficult and hard to confirm "clean".
>>
>> Dave Hillman
>> Rockwell Collins
>> [log in to unmask]
>>
>> On Fri, Nov 3, 2017 at 10:39 AM, Ed Popielarski <
>> [log in to unmask]>
>> wrote:
>>
>> > Hi Technetters,
>> >
>> > I have 2 questions:
>> >
>> > 1: How is this oxide formed?
>> > 2: is there a "safe" way to clean it after the fact?
>> >
>> > On very rare occasion, we have a "verdigris" outbreak on Tin plated
>> solid
>> > Cu wire. The insulation tends to not be well adhered (PTFE) when this
>> > "breaks out" The stripped wire looks "normal" but when soldered with OA
>> > flux (either hand or wave) it starts showing a blue-green oxidation at
>> the
>> > insulation/wire interface. Wetting is marginal at best. Scrapping the
>> wire
>> > and going to a different manufacturer usually resolves it, but there's
>> > still labor involved since it doesn't show up until later in the
>> process &
>> > must be reworked.
>> >
>> > Thanks in advance!
>> >
>> > Regards,
>> >
>> > Ed Popielarski
>> > Engineering Manager
>> >
>> > [cid:[log in to unmask]]
>> >                                970 NE 21st Ct.
>> <https://maps.google.com/?q=970+NE+21st+Ct.+%0D+%3E%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0Oak+Harbor,+Wa.+98277+%0D+%3E+%0D+%3E%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0Ph:+360&entry=gmail&source=g>
>> >                               Oak Harbor, Wa. 98277
>> <https://maps.google.com/?q=970+NE+21st+Ct.+%0D+%3E%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0Oak+Harbor,+Wa.+98277+%0D+%3E+%0D+%3E%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0Ph:+360&entry=gmail&source=g>
>> >
>> >                               Ph:
>> <https://maps.google.com/?q=970+NE+21st+Ct.+%0D+%3E%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0Oak+Harbor,+Wa.+98277+%0D+%3E+%0D+%3E%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0+%C2%A0Ph:+360&entry=gmail&source=g>
>> 360-675-1322
>> >                               Fx: 206-624-0695
>> >                               Cl: 360-544-2289
>> >
>> >
>> >
>> >        "It's one kind of victory to slay a beast, move a mountain, and
>> > cross a chasm, but it's another kind altogether to realize that the
>> beast,
>> > the mountain, and the chasm were of your own design."
>> > https://goo.gl/maps/mMjg43rXeFB2
>> >
>>
>
>
>
> --
> Steve Gregory
> Kimco Design and Manufacturing
> Process Engineer
> (208) 322-0500 Ext. -3133 <(208)%20322-0500>
>
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