Lead-Free vs. 63/37 tin/lead solder

I don't do much soldering (obviously) but which is better and is less prone to cracking in the future? The newer Lead-free rosin core or the

63/37 tin/lead rosin core? A store in my town only stocks these two. This for a small circuit board repair project.

Also, What can I use to cleanup the dried-up rosin residue on the PCB?

Thanks

Reply to
Phillip77776666
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Forgot to mention; Another store nearby stocks 60/40 tin/lead rosin core (says acid core) and the same kind but its made without the rosin flux. So many to choose from; they are all around $12.00 a small spool.

Reply to
Phillip77776666

Unless you are working with circuits that have known lead-free solder on it, go with the 63/37 rosin core. Usually it is more common to find a 60/40 rosin core, but either is fine with a slight preference to the 63/37. If you look at a chart for the melting and cooling of the solder, you will see that the 63/37 does not go into what is called a plastic state as it cools. What that is , as the solder cools and if the joint is moved, the solder will have a frosted look and will not make a very good joint. It will not be shinny as it should look.

Never use the acid core for electronic work. The acid left behind will absorb water from the air and eat away at the circuits. The acid flux is mainly used for copper water pipes.

Reply to
Ralph Mowery

For repairs, I'd use the lead/tin solder.

I've always used methylated spirits (very cheap & easy to find) & a stiff paintbrush, but any other kind of pure alcohol should work just as well.

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   W          
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Reply to
Lionel

Lead free solder is specially formulated to fail after not more than 1 year because the landfill sites aren't filling up with scrap electronic equipment fast enough!!!

Reply to
ian field

As long as that ?? Panasonic and Sony must have got their formulations wrong. Theirs fail after 6 weeks ...

When looking at how good ( ! ) lead free solder is, you might ask yourself why the US military refuse to go near the stuff, and the avionics and medical instrument industries are exempt from the new rules concerning the hateful stuff, which are now spreading around the world ...

Arfa

Reply to
Arfa Daily

Phillip -

NEVER use acid core solder on electronic circuits (or kiss that appliance / project goodbye).

63 / 37 is the Eutectic of Tin and Lead metals. Eutectic is an English word that comes from the Greek 'eutektos', meaning 'easily melted.'

The lowest temperature at which a mix of two materials will melt. Often the temperature is an anomaly, that is, it is much lower than the melting temperatures of only slightly different mixtures. Lead-tin solder is an example. Lead melts at 327 C, tin at 231 C. The lowest melting combination is 67 lead, 33 tin ( 180 C ).

Non-eutectic mixtures have a melting or softening (plastic) range. Such mixtures do not flow well until thoroughly heated past the softening (plastic) range. Kester solder Alloy temperature chart

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g. beat

Reply to
g. beat

If you have the choice use tin-lead every day !

Do you need to ?

Most of the alcohols work fine for this. Isopropyl alcohol ( aka isopropanol ) is probably best and easy to obtain.

Graham

Reply to
Pooh Bear

*NEVER* use acid core for electronics.

Graham

Reply to
Pooh Bear

An exemption has also been applied for regarding pro-audio.

Graham

Reply to
Pooh Bear

Look for the tin/lead stuff, I've used lead free and hate it.

Reply to
James Sweet

Pooh Bear spake thus:

Amen to that.

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Reply to
David Nebenzahl

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I'm a bit confused about the talk of not using acid fluxed solders in = electronics. Just about all conventional solder wires formulated for = electronic work, contain one or more cores of rosin based flux. As far = as I am aware, this is a fundamentally acidic material when in its = activated state, and in fact its being acidic is how it removes the = tarnish and oxidation on the surfaces to be joined.

Recent research that I have done regarding the use of lead free solder = wire for repair and rework purposes, suggests that because of the = inferior wetting properties of lead free, the fluxes employed are = actually more aggressive than those in leaded solder, by virtue of being =

*more acidic*. This is cited as being a reason that lead free soldering = is considered to be potentially more injurious to health than leaded = soldering, and that workshops should take steps to improve fume = extraction.

I obtained this information on very good authority, directly from a = recognised specialist, working for a company whose job it is to = recommend on such matters. Comments please ??

Arfa

Reply to
Arfa Daily

Reply to
Pooh Bear

Sorry, don't know how that got switched on. It's set for " plain text " again now, as it usually always is ...

So, aside from the formatting gripes, any comments on what I was really asking :- ) ? It's a serious question that I'm interested in answers to. There must be some posters who better understand the chemistry of soldering and flux than I do.

Arfa

Reply to
Arfa Daily

IIRC you were commenting on acid fluxes. The difference is that organic acid fluxes ( like rosin ) are essentially inactive at average 'room' temperatures AIUI, so present no long term risk.

Graham

Reply to
Pooh Bear

soldering

You don't really have to understand it, just use rosin for electronic work. It is almost nonreactive with the components when not heated. The acid flux will absorb water from the air and eat the circuits.

Reply to
Ralph Mowery

"Arfa Daily" wrote in news:GW3ig.10691$ snipped-for-privacy@newsfe2-gui.ntli.net:

It's all a matter of words.

Here's the deal. For decades there have been two classes of flux used for soldering.

  1. Acid. This contains strong chemicals to aggressively clean the metals and is used only for plumbing and similar soldering. It must be cleaned from the joint after soldering, or corrosion will occur. It has NEVER been used for electronic work because of this corrosion.

  1. Rosin. This is the only flux used for electronic work. It contains such mild chemicals that it doesn't need to be cleaned after soldering.

Your worry is about "acidity", which is probably nothing to worry about, as long as you stick to rosin flux and never, ever, use "acid flux."

Reply to
Jim Land

OK, thanks for the answers. I don't have any " worries " about fluxes. It was just curiosity as I have never seen anyone making the distinction before with regard to electronic soldering. I have been soldering virtually every day of my life for 40 odd years, and have always used 'standard' rosin flux cored solder, which was the only variety I had ever seen offered for normal electronic work. I had always understood the material rosin, to be mildly acidic, at least in its activated form, and that this was the basis of its deoxidising properties. This was the only reason that I was interested in comments about " never use acid flux " ( I was not the OP having soldering problems, incidentally ).

So it would seem that the point is academic anyway, as such fluxes are not offered for electronic work, and anyone dumb enough to try to use plumber's flux would deserve all they got ...

Just as a matter of interest, I always remove rosin flux residues from boards, using a proprietory flux remover from Electrolube. IMHO, post soldering residues left on boards make the job look scrappy and unprofessional. A couple of years back, I took over the repair of some commercial boards from another company, who never cleaned up their work. Interestingly, when I now see boards in for repair, that they did a couple of years back, the joints and print area around where they've left flux residues, often look slightly corroded. The air around them in their normal working environment, is likely to be slightly moist, and the components that have been replaced, run hot in normal use, so I wonder if this is slightly reactivating the flux residues ?

Arfa

Reply to
Arfa Daily

Good thing I found this group and asked before I bought anything, the guy at the store counter told me acid core is mainly used for electronic work and at the other store, the salesperson said to use rosin core. Thats what confused me; I bought the 63/37 tin/ lead rosin yesterday and the soldering work turned out OK. Thanks for the help! Phillip

Reply to
Phillip77776666

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