What is the purspose of pre-tinned wire?

The only problem which can occur with tin plating is the growth of "whiskers" but this is relatively rare except in particular environmental conditions. Tin plated conductors are never used in aerospace environments because of whisker growth.

: :Irrelevant!!! : :These papers deals with using 60/40 tin-lead solid core flux solder and has :nothing to do with the tin plating on copper conductors in cables. Conductors :are plated using either the hot dip plating process or electroless deposition, :and the plating is usually only around 5 - 10 microns thick and it becomes :essentially part of the copper alloy itself. I have never heard of tin plating :on copper conductors "creeping" in any type of connector.

:On Fri, 17 Apr 2009 04:14:40 +0100, Sandi wrote: : :>Some insulated multistrnd copper wire is pre-tinned and a lot is :>not. :>

:>What is the purpose of pre-tinned wire? As far as I can see the :>advantage is that the copper core doesn't oxidise which means the :>wire can be soldered or fixed to a terminate with only minimal :>cleaning. :>

:>Sounds like a good thing to me, so why isn't almost all wire pre- :>tinned? :>

:>Is cost really so different? :>

:>Does the tinning-coating replace where copper would have been in :>the overall wire and tinning is of higher reistence? :>

:>Is flexibility affected? : : :In the telecom industry the rule is "silver on silver". Back in the :bad old days there could be problems with diss-simmilar metals :corroding & creating noise on circuits both from rectification effects :& from current punch-through across the junction when voltage was :applied to the circuit, i.e. "going off-hook". In some cases :"sealing" current was (& still is) applied on a constant basis to :circuits that didn't require it for operation, just to keep junction :corrosion from getting bothersome. : :Although not part of the original Bellcore standard I've actually :speced tinned wire for T1 circuits going into areas I knew were going :going to be climate controlled. : :H.

That is correct. A typical manufacturer of internal switchboard cable application chart shows that their Switchboard 100 product (equivalent to what most western countries would use for internal cabling) is suitable for T1 and DS1 applications.

--- What does that crap have to do with anything?

The point is that the tarnish found on silver, including the plating on silver plated copper wire isn't, as you claimed, silver oxide, it's silver sulfide.

Which makes you the dope, yes?

From:

Silver metal does not react with sulfuric acid, which is used in jewellery-making to clean and remove copper oxide firescale from silver articles after silver soldering or annealing. However, silver reacts readily with sulfur or hydrogen sulfide H2S to produce silver sulfide, a dark-coloured compound familiar as the tarnish on silver coins and other objects. Silver sulfide also forms silver whiskers when silver electrical contacts are used in an atmosphere rich in hydrogen sulfide.

. . .

Silver oxide (Ag2O) produced when silver nitrate solutions are treated with a base, is used as a positive electrode (cathode) in watch (battery) batteries.

JF

ALL I CAN THINK OF BESIDES THE FACT THAT WIRE ONLY INTENDED FOR SOLDERING SHOULD BE TINNED IS THAT IT IS DEEP PROBE TIME AT THE TROLL FARM

I AM PROTEUS

No, oxide/sulfide is not what makes DimBulb a dope.

That showed him up. Hee hee! You owned him.

Those references to CHILDREN'S experiments!!!

Children are not qualified engineers.

Is this a sign of desperation?

Not sure I understand why this exchange got so lively. You wrote this:

"Tin plated wire is notorious for NOT taking solder, especially when it is inside teflon."

Assuming you wrote what you meant to write then you said "tin plated wire is notorious for NOT taking solder". You also added that furthermore it was even harder still to solder tin plated wire when it was inside Teflon insulation.

Aren't some posters responding to your clearly made statement that

"Tin plated wire is notorious for NOT taking solder"

because it probably seems a bit unexpected to them? I have to confess it does a bit unexpected to me too. It doesn't relate to my experience or known facts.

The Teflon insulation you mention is an additional observation which you offer as an extra fact but it's not particularly relevant to the OP's question.

Seems to me this discussion is based around your statement:

"Tin plated wire is notorious for NOT taking solder"

Hmmm then Rust is actually Iron Sulfide?

I thought a high concentration of Sulfur had to be present for sulfidation to occur.?????????????????????????????????

ARCHIMEDES' IS A DESPERATE CHILD WITH CRIMINAL TENDENCIES THE SAD MELANCHOLIC OFF SPRING OF A CROSS BETWEEN HUMAN AND FAIRY TALE TROLL I CAN'T IMAGINE WHAT HIS PARENTS WERE THINKINGAT THE TIME NOR DO I THINK I WANT TO BUT THERE MUST BE A FILE A BOOK OR A FANTASY NOVEL SOMEWHERE THAT EXPLAINS IT

I AM PROTEUS

You are so retarded that you do not even know what solder creep is, much less how it relates to failure modes in cinched connection terminations.

If you've ever worked with both SPC and TPC, you would know that SPC takes solder an order of magnitude better than TPC does.

You all also seem to miss the 'ide' part of all this. It may not be "Silver Oxide"itself, but even the 'tarnish' that is based on grabbing sulfur molecules out of the air, is still an oxidation process.

Sulf-IDE

I hadn't missed that at all as I pointed out in the first post I made it is a redox reaction. However oxidation products are not always oxides - burn a jet of chlorine gas in a hydrogen atmopshere and chlorine is reduced, hydrogen is oxidised, the oxidation product is hydrochloric acid and no oxygen or oxide is to be found....

Ooops- typo, I meant to say I spec'd tinned wire for areas I knew were *not* to be climate controlled.

More specificly DSX panels mounted outside in un-heated, not particularly weatherproof, cabinets.

H.

Its the 40 + generations of inbreeding. His family tree is just a rotting stump. :(

Sad that the history of Alzheimer's and senility that runs in your family is also obviously taking your mind as well.

Well, maybe it's not so sad after all...

Soon enough, he'll catch up to Thompson.

UpGrade'ing Mr. Haney ought to be a cinch !