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How long does it tkae for Tin-Lead solder to rust if put outside

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How long does it tkae for Tin-Lead solder to rust if put outside - Sep 27, 2007 by Novaman  

#51915

How long does it tkae for Tin-Lead solder to rust if put outside | 27 September, 2007

Hi everybody,

I did post in the past last year and I always got good answers.
If I'm going to solder something with Tin-Lead solder and then put it outside (it will be exposed to water, sun, cold nights,...), how long does it take starting to rust?
Is there any formula, thumb rule?

Thanks

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#51919

How long does it tkae for Tin-Lead solder to rust if put outside | 27 September, 2007

The short answer is immediately after reflow the problem occurs. To be more exact, what you are describing is not "rust". Rust occurs in iron. The oxidation that occurs in Tin-Lead has been sometimes called "white rust".

Either way, oxidation occurs immediately after exposure to oxygen. You are suggesting the potential for environmental conditions that will affect your PCA. Depending on the severity, a no-clean process can be a conformal coating like protective barrier that will greatly reduce the oxidation. If a harsh environment is to be experience, the answer to prevent the oxidation would be conformal coating.

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#51924

How long does it tkae for Tin-Lead solder to rust if put outside | 27 September, 2007

Yes of course,

From Wkipedia:
"As rust has higher volume than the originating mass of iron, its buildup may force apart adjacent parts - a phenomenon known as rust smacking."

The smacking formula is as follows; again from Wikipedia:

"Fe(s) -> Fe2+(aq) + 2e-
"harply, but this is of no consequence since OH- ions are always present, even in pure water.) The cations then react with the OH- or even the H+ ions and dissolved oxygen to form a variety of compounds, which constitute rust:

Fe2+(aq) + 2OH-(aq) -> Fe(OH)2(s)

4Fe2+(aq) + 4H+(aq) + O2(aq) -> 4Fe3+(aq) + 2H2O(l)

Fe3+(aq) + 3OH-(aq) -> Fe(OH)3(s)

From the above equations, it is seen that the pH and amount of dissolved oxygen can affect the outcome of the reactions. In water with limited dissolved oxygen Fe3O4(s) is formed, which is a black solid and commonly called lodestone:

6Fe2+(aq) + O2(aq) + 12OH-(aq) -> 2Fe3O4(s) + 6H2O(l)

The porous Fe(OH)3 rust can slowly disintegrate into a crystallized form, which is the familiar red-brown rust:

2Fe(OH)3(s) -> Fe2O3�H2O(s) + 2H2O(l)

Iron oxide (FeO) can also be formed. The presence of other ions, such as calcium or calcium carbonates reacts with the iron hydroxides and iron oxides to form a variety of precipitates. Other metals corrode via similar chemical processes."

Now we got the other variable you called "tin-lead-something" to put into the equation:
The short answer to this is: yes, it will take some time, more than a while...

Best Regards, Mika
Ps. If you are going to solder something to be exposed "outside", concider to glue the whole thing. Maybe some other nice fellows at this forum can tell you how. Ds.

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#51925

How long does it tkae for Tin-Lead solder to rust if put outside | 28 September, 2007

Maybe this can be useful for you.
Just to get you a hint of how it works and why...

We have no relationship, nor any benefits from them.
Best Regards, Mika
Ps. How often have we not been seeing this slogan: "leading manufacturer of high performance xxx" Ds.
http://www.masterbond.com/produse/produse_cc.html

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#51947

How long does it tkae for Tin-Lead solder to rust if put outside | 1 October, 2007

A simple answer is never. Tin lead will oxidize when exposed to oxygen, but it will not rust away like normal steel. I have old equipment from the 1920�s and 1930� that have solder joints as robust as the day they were made. Maybe not as shinny, but far from where this thread was going.

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#51948

How long does it tkae for Tin-Lead solder to rust if put outside | 1 October, 2007

Thanks to all of you for the answers.

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#51956

How long does it tkae for Tin-Lead solder to rust if put outside | 2 October, 2007

So, a test probe from ICT will not make solder rust?

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#51961

How long does it tkae for Tin-Lead solder to rust if put outside | 3 October, 2007

No! Go back to your sheep.

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#51962

How long does it tkae for Tin-Lead solder to rust if put outside | 3 October, 2007

The simple answer is probably a lot longer than it'll take for it to short circuit due to moisture of some sort bridging two conductors. I say moisture of some sort because it doesn't necessarily have to be liquid water. A slug will do nicely.

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#51963

How long does it tkae for Tin-Lead solder to rust if put outside | 3 October, 2007

Dang back button!

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#51990

How long does it tkae for Tin-Lead solder to rust if put outside | 5 October, 2007

Hussman, I don't understand the last sentence of yours "but far from where this thread was going". What do you mean with that?
I was just trying to give "Novaman" some infos. The fine old equipment You use from the old -20:s or so, is probably just as fine as it should be. Nevertheless it is a fact that even that old fine machinery will have corrosion!
Even under the paint. It will take some time, but it will happen. Slowly. No matter what!

The first 2 questions in this thread was "how long does it take starting to rust?
Is there any formula, thumb rule?"

This is a couple of a very complex questions to answer and I am sorry that I couldn't give the perfect answer.
It was just to give away a hint of how complex this is, no more.
Sincerely, Mika

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#52007

How long does it tkae for Tin-Lead solder to rust if put outside | 9 October, 2007

What do you mean by "what do you mean"? I was just making fun. But if you want, you can take it the wrong way and blame me for everything.

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#52011

How long does it tkae for Tin-Lead solder to rust if put outside | 10 October, 2007

Hussman,I'm quite happy to exist alone in his swamp and dine on delicacies like pickled eyeballs.

This means you, me lad. BACK OFF!

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#52014

How long does it tkae for Tin-Lead solder to rust if put outside | 10 October, 2007

LISTEN our old Soltec never rusted so i don't know where all this nonsense with rust is going.

Mika, how about that gobblett we were supposed to have together? ;-)

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#52051

How long does it tkae for Tin-Lead solder to rust if put outside | 12 October, 2007

His swamp? What?

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#52059

How long does it tkae for Tin-Lead solder to rust if put outside | 12 October, 2007

Hussman, I'm sorry that I was a little bit tired and on top of that not so sensitive to your humour. Not so easy to understand everything for us Swedish guys. We have normally a great sense of humour over here and almost daily we have a big laughs at work. Even at the "hard days", because it will help us to "get trough and make a better work".

WaveMasterLarry, of course and I have already start preparing for that. I will now start fill the goblets up and it is for you to come with a big smile... There is also an old Swedish text on the goblets: You must only drink this up, if you can make the host laughing. That's the reason why I laugh at my girlfriend and vice versa...

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