Hello everyone,

This is off topic, but I've tried to post to the Technet a few times over
the last couple of days and I can't.

Just want to see if a reply to this message gets through....

Steve

On Mon, Mar 11, 2024 at 8:07 AM [log in to unmask] <
[log in to unmask]> wrote:

> Let me correct that sentence:
> For very large quantities of wires, there are machines that will cut the
> wires to length, strip to length, and then dip the stranded ends first into
> IPA or some other solution simply to clean the wires prior to tinning, then
> dip them into the RMA/NC flux, dip and hold in the solder for 2 seconds,
> and then drop them into a container of IPA or a solvent compatible with the
> NC/RMA flux.
>
>
> -----Original Message-----
> From: TechNet <[log in to unmask]> On Behalf Of [log in to unmask]
> Sent: Monday, March 11, 2024 7:40 AM
> To: [log in to unmask]
> Subject: Re: [TN] Metallurgical Inquiry
>
> ----
> External E-mail --- CAUTION: This email originated from outside GDMS. Do
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>
> OA is organic acid flux, typically much more corrosive and should not be
> used with stranded wires. No clean and RMA fluxes are typically very
> similar to each other, and only mildly corrosive at best.
> I am a VERY old dog, and worked in my father's shop tinning wires back in
> the 60s. We would use the methods I described.
> When I started working for Honeywell in 1978 they did it exactly the same
> way, but for wire cups used on connectors as well as many other types of
> gold-electroplated terminals.
> When I worked for various other companies, they also did it the same way.
> Tyco, Benchmark, ADC, you name it.
> That is how we do it today at Analog Technologies Corp., Kongsberg Defence
> AS, and at General Dynamics, and have done so for more than 20 years.
>
> Never use water-soluble or OA fluxes with stranded wires. As Dr. Kondner
> pointed out, it will wick up the wires as the solder wets up the strands.
>
> RMA or no-clean flux residues are mostly removed if you simply let the
> wires soak in a pan of IPA or a similar solvent intended for those types of
> flux, immediately after tinning. Then wash in DI water with a good
> saponifier. What works really well is to do the final cleaning step in an
> Ultrasonic cleaner with a saponifier, provided you are only cleaning
> mechanical terminals/wires, no electronics, at least not without fully
> qualifying the process for the electronics.
> As I stated, any minor flux residues left after this process is followed,
> is typically so negligible as to present little or no risk.
> As for the solder going too far up under the insulation, that is
> controlled by operator training. IPC is very clear on this, stating that
> the solder should not wick up under the insulation more than 1 or 2 wire
> diameters, but it must wick up somewhat to prevent birdcaging. For very
> large quantities of wires, there are machines that will cut the wires to
> length, strip to length, and then dip the stranded ends first into IPA or
> some other solution simply to clean the wires prior to tinning, then dip
> them into the RMA/NC flux, and then drop them into a container of IPA or a
> solvent compatible with the NC/RMA flux.
>
> A relatively simple process, but it must be done right.
> Odin
>
> -----Original Message-----
> From: Robert Kondner <[log in to unmask]>
> Sent: Friday, March 8, 2024 2:44 PM
> To: 'TechNet E-Mail Forum' <[log in to unmask]>; Stadem, Richard D <
> [log in to unmask]>
> Subject: RE: [TN] Metallurgical Inquiry
>
> ----
> External E-mail --- CAUTION: This email originated from outside GDMS. Do
> not click links or open attachments unless you recognize the sender and
> know the content is safe.
>
> Hi,
>
> I recall that with stranded wire it is not a good idea to solder. Flux
> wicks up into the wire and it just cannot be washed away. Most no clean
> fluxes are type OA (correct me here) which is corrosive and needs to be
> cleaned. RMA is better.
>
> Solder also wicks up into the stranded wire making the wire very stiff.
> This concentrates any flexing to the solder point which can fail. Crimping
> stranded wire give some level of strain relief and this is why the
> soldering of stranded wire in crimp terminals is not recommended.
>
> But, I am an old dog and my memory could be failing. Please let me know.
>
> Bob K.
>
> -----Original Message-----
> From: TechNet <[log in to unmask]> On Behalf Of [log in to unmask]
> Sent: Friday, March 8, 2024 1:19 PM
> To: [log in to unmask]
> Subject: Re: [TN] Metallurgical Inquiry
>
> It is not recommended. I would first tin the terminals using RMA flux to
> remove the gold. Tin the stranded wire with either RMA or no-clean and soak
> in IPA, then blow off thoroughly and wash with a good saponifier, bake dry,
> and then solder the tinned wires to the tinned terminals with the same
> NC/RMA flux and clean again the same way. Do not use DI water first. Clean
> off (or at least dilute) as much of the flux as you can with IPA, then
> clean with water.
> Otherwise you will have a reaction between the DI water and the
> no-clean/RMA flux (white conductive residue).
> Any flux residues that might remain after cleaning will be negligible.
> Dean
>
> -----Original Message-----
> From: TechNet <[log in to unmask]> On Behalf Of Hernandez, Victor G
> Sent: Friday, March 8, 2024 11:19 AM
> To: [log in to unmask]
> Subject: [TN] Metallurgical Inquiry
>
> ----
> External E-mail --- CAUTION: This email originated from outside GDMS. Do
> not click links or open attachments unless you recognize the sender and
> know the content is safe.
>
> Fellow TechNetters:
>
>     Is it permissible to solder a stranded wire to a gold finger pads with
> either Sn Pb or Pb-free solder?
> Typically, gold fingers are electroplated, hard gold.
> Any chance of galvanic corrosion?
>
> Victor,
>
>
>
>
> Internal Use - Confidential
>


-- 
Steve Gregory
Kimco Design and Manufacturing
Process Engineer
(208) 322-0500 Ext. -3133
Cell Phone: (918) 706-2779

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