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So what's the truth about lead-free solder ?

Discussion in 'Electronic Repair' started by Eeyore, Jul 24, 2007.

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  1. N Cook

    N Cook Guest

    So when I pull , with just finger tension, a component lead through what was
    a lead-free solder joint only a year or so before and there is a grey
    powdery looking surface to the lead where it had been inside the solder
    joint - is that "tin pest" ?
     
  2. Eeyore

    Eeyore Guest

    It could well be I suppose. Here's the problem, we're in 'uncharted territory'
    here because the EU insisted on going down this path before the science was
    well-established. Document it. It has serious implications for the classic
    practice of keeping MI gear in the van / truck, in the (unheated) garage etc.

    I'd love to see the idiots at the Commision in Brussels forced to eat humble
    pie. It's about time that Emperor Barroso's new clothes were seen for what they
    are.

    Graham
     
  3. Eeyore

    Eeyore Guest

    Do you always talk shit ?

    Graham
     
  4. Guest

    You just named the problem with Multiwire--wire is sequentially
    applied
    to a thermoplastic substrate.

    Whatever other advantages or problems it may have, it is a
    *prototyping*
    process, not a mass production process. It is to PCB production as
    e-beam is to photolithography.
     
  5. Tin Whiskers:-

    For those who though leaded solder was best.
    Here is the problem with lead free solder.

    http://pubs.acs.org/cen/science/85/8529sci1.html

    Colin
     
  6. Arfa Daily

    Arfa Daily Guest

    And in the meantime whilst smaller manufacturers who don't have the
    resources of the big boys to research this crap in sufficient detail to find
    the 'correct' process to replace the previously utterly reliable and simple
    leaded soldering that they were using, cartloads of electronic equipment are
    failing as a result of the bad joints that the experimentation or 'best fit'
    replacement alloys are causing.

    I wonder what qualifies you to make that remark at the beginning of your
    post, telling people not to look to this group for 'factual' information on
    lead-free ? When I tell you that I work day in day out with equipment from
    major manufacturers that uses the stuff, and that since they have been using
    it, I have seen the incidence of bad joints in places that would never
    previously have suffered, skyrocket, do you consider that to not be
    'factual' ? Am I lying perhaps ? There are many good engineers that
    contribute to this group, and most have reported seeing an increase in such
    bad joints. Are they all being less than 'factual' ?

    When push comes to shove, this is an electronic repair group, frequented by,
    amongst others, repair professionals who have to deal with the effects of
    legislation such as RoHS, and its implications, at the sharp end, which is
    more than the manufacturers and political activists / pseudo scientists
    responsible for creating these situations, do. As such, I feel that it is
    therefore rather presumptuous of you to suggest that opinions voiced on this
    group, are not based in fact, and thus not valid.

    Arfa
     
  7. Most "solder creep" (the expression which describes your scenario)
    failures can be tracked back to a poor design as it relates to fixturing
    large masses or "tugged on" components or interconnects. Such elements
    should be fixtured by means other than the soldered leads.

    It was unclear to me whether your situation was a remark about how
    quickly a lead free assembly exhibits such failure, or about older.
    leaded solder alloys in assemblies.

    And for solder, it was entirely NOT necessary.

    The other substances perhaps, but not for solder.
     
  8. "Data" is a collection of values or attributes for a given observation.

    "Information" is processed data.

    What you are looking for is information.
     
  9. But we know which solder you really used. Of course, you have to pretend
    you used the PbF stuff. Just be careful that the lead nazis don't audit
    your purchasing of lead content...

    Leonard
     

  10. If the water tables around an outdoor shooting range had any higher
    levels of lead leeched into them, the whole world would know about it,
    and that is what we call NEWS.

    FACT is that there is no such lead level increase in such areas, and
    they dump TONS of lead into the ground at popular ranges.

    FACT is that I have been touching, rubbing, etc. lead alloy soldered
    circuit card assemblies (as well as the solder itself) my entire adult
    life, and my lead levels are lower than the doc had previously seen for
    someone my age, the last time I had that test taken ( about four years
    ago).
     
  11. And that's if Global Warming doesn't get us first...

    If you believe that to be a possibility, are you not concerned about the
    additional carbon based fuels used to heat these lead free solders to the
    higher temperatures that they require?

    Leonard
     
  12. Fully operating incinerators are sprinkled all over this country. There
    was even some twit on TV the other day claiming that their placement was
    racist.
    Do you know the rate that pure Lead oxidizes? Do you know the rate at
    which 63/37 Tin Lead Solder oxidizes at?

    Bullets are still being found in old US Civil War battle fields, and
    they are practically pristine balls. No crust whatsoever.

    What actually happens with pure Lead is that it's first few mils of
    depth become "tempered", similar to aluminum anodization.

    So it becomes harder, and would oxidize even less.
     

  13. And lead free utilization does exactly what against these elements and
    compounds?
     
  14. There are SEVERAL HDTV set top tuners out there that will pipe the
    finished signal into a standard TV. What is nice about digital
    broadcasts is that when you have the signal, you have it all. No snow,
    No herringbone patterns. Crisp and clean, with no caffeine.
     
  15. Eeyore

    Eeyore Guest

    Except when it breaks up.

    Graham
     

  16. That's what cost Napoleon dearly in Russia. He lost his armies to
    exposure due to their uniforms literally falling off their bodies.

    All Tin buttons, even on their boots.

    http://ds.dial.pipex.com/town/terrace/adw03/c-eight/france/moscow.htm
     
  17. Arfa Daily

    Arfa Daily Guest

    Afraid not, Leonard. I take my responsibilities under the law, seriously. I
    always rework lead-free joints with lead-free solder, as I am required to
    do. Perhaps I am silly for doing so, and it's not to say that I don't think
    that I am compounding poor construction techniques with a poor repair, but
    never-the-less, I do comply. Of course, a great deal of the kit that I work
    on is constructed with leaded solder as it pre-dates the legislation, and
    for those repairs, I do indeed use my SnPb solder inventory ... d;~}

    Arfa
     
  18. There have been polymer based conductive circuit assembly adhesives
    around for several years now.

    NOT cheap.

    The answer will be Rhodium alloy solders for safety and mission
    critical applications... perhaps.
     

  19. Most VME backplanes utilize a press fit pin, directly into a clad hole,
    and it is gas tight in the connection regions and there is no solder
    involved. Lasts for years and years.
     
  20. Arfa Daily

    Arfa Daily Guest

    That's worrying ...

    Arfa
     
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