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More on lead-free junk solder

Discussion in 'Electronic Repair' started by N Cook, May 10, 2007.

  1. N Cook

    N Cook Guest

    A 200W combo, UK made 2002, with one solder joint to a small on-end
    electrolytic failed
    so could be just due to vibration/resonance.
    But it is on a board with obvious conical solder joints so perhaps the most
    likely inherently weak joint to fail first. The larger (heatsinky) joints
    are shiny and conical, redone by hand with junk solder maybe, but all the
    other small joints look horribly grey. On the other board all conical joints
    but all bright silvery colour. What is the consensus of the panel - redo all
    the grey joints with Pb-Sn solder and leave the bright ones, or if it aint
    broke - don't poke. ?
     
  2. Have you checked for zinc migration?

    I have no idea if that is still common, but I have some older 70:s and
    80:s stuff where this happens on some connectors and switches that
    appears to have been of incompatible material.
     
  3. Guest

    There are some very nice silver-bearing electronics solders out there
    that do not fail under stress.

    http://www.all-spec.com/1/viewitem/KWLF24555/ALLSPEC/prodinfo/w3path=cat

    Comes to mind. It ain't cheap... I have used it with success, with
    specific reference to R/C submarines... stressful conditions, high
    dampness, vibration, several amps on the connections and considerable
    heat.

    Failing that, 63/37 tin/lead solder is your best bet, and my tipple of
    choice for my normal (vintage radio/audio restoration/repair) uses.

    Peter Wieck
    Wyncote, PA
     
  4. Arfa Daily

    Arfa Daily Guest

    I really can't make my mind up on this. All the regulars on here know my
    views on lead-free solder, and I must admit that I am inclined to go over
    lead-free joints that look *particularly* suspicious, with //proper//
    solder, but as I've said here before, there are two schools of thought on
    this among the metallurgical experts as to whether mixing lead-free and
    leaded solder in the same joint, produces one with long-term compositional
    stability.

    Add to this that now the full legislation for RoHS is in place, as UK
    repairers, we are fully obligated, officially under threat of EU law, to
    repair equipment originally constructed with lead-free solder, and placed on
    the market after July 2006, using *only* lead-free. This means that by
    reworking a lead-free joint on such an item with leaded solder, we are
    officially inviting the wrath of the solder police, and I guess, prosecution
    for what they are now calling an " eco crime ".

    I haven't heard of any such prosecutions yet, but in these days that we have
    now where people are getting prosecuted and heavily fined for (
    accidentally ) putting the wrong type of recycle waste in their household
    bins, I'm sure that the day can't be far away when some poor engineer gets
    tricked into breaching the legislation, by some over-zealous trading
    standards person ...

    Arfa
     
  5. Ian Jackson

    Ian Jackson Guest

    Are you sure about this? My understanding is that leaded joints can
    still be repaired with leaded solder.

    Ian.
    --
     
  6. Arfa Daily

    Arfa Daily Guest

    Read a bit more carefully - that's " lead-free " ....

    Arfa
     
  7. Ian Jackson

    Ian Jackson Guest

    Oops! I misread that. Sorrrrry.
    Ian.
    --
     
  8. Arfa Daily

    Arfa Daily Guest

    No probs, Ian. You are right, of course. For those not familiar, the
    situation is that any equipment 'placed on the market' before July 2006,
    irrespective of what technology has been used to manufacture it, may be
    repaired by any technology that you see fit - ie by using leaded or unleaded
    solder. However, common wisdom is that if it was manufactured in lead-free,
    then it should be repaired in lead-free, likewise for leaded manufacture,
    used leaded solder. However, it is getting impossible to buy new components
    now that are not lead-free, which //may// mean that their legs have been
    dipped in a lead-free solder ...

    Some manufacturers, notably Sony, have insisted for several years now, that
    all of their official service centres use only lead-free to repair *all* of
    their products, irrespective of original manufacture technology. The service
    bulletin that was sent out by them regarding this, actually caused
    considerable misunderstanding in the UK repair industry, with regard to what
    was the correct legal situation. I am of the opinion that you should
    probably not mix solder types if at all possible in a joint but, like most
    reading this I suspect, I just can't help myself when I come across a bad
    joint in a place that I know is not going to be reliable if reworked in
    lead-free.

    Equipment placed on the market after July 2006, must have been manufactured
    in lead-free, and the directive says that we must not compromise this, so
    must use lead-free solder and RoHS compliant components to effect any
    repairs. The exception to this, is where an equipment has been granted an
    exemption from the directive. Such equipment includes avionics and medical
    and some military equipment. This will have continued to be manufactured in
    leaded solder, and marketed quite legally. Repair of such items can - and in
    my opinion *should* - be effected using leaded solder.

    Arfa
     
  9. N Cook

    N Cook Guest

    If the manufacturing date is not on the back of a bit of kit needing repair,
    then presumably its a matter of saying you cannot repair anything made in or
    after 2006 , then asking the owner when he thinks it was made, and then
    making the appropriate comment.
     
  10. Arfa Daily

    Arfa Daily Guest

    As you say, this is one of the difficulties, and where a typical piece of
    euro-mumbo-jumbo, however well intentioned, comes unstuck for lack of being
    properly thought through in terms of the poor sods who have to be
    responsible for its implementation at the sharp end. In years gone by, date
    of manufacture was commonly stamped inside the cabinet, or on the chassis.
    Now we're going to have to rely on our abilities to read component date
    codes, or plastics moulding date clocks in the back covers.

    I have, however, started to see the legend "PBF" or "PbF" appearing on
    PCBs. Whilst I accept that this doesn't necessarily mean a build date ( or
    marketing date ) of post July 2006, it does at least confirm what we might
    already suspect just by looking at the dubious grey joints on the board, and
    in theory, if only for the reason that no-one is really sure of the
    long-term effects of mixing solder types, it would indicate that we should
    be using lead-free to repair it.

    At the end of the day, all of this is just another way to make our lives
    unnecessarily complicated for no well-defined reason. For many years, my
    wife owned a childrens' day nursery. It got buried in more and more and more
    layers of rules and regulations until the whole day was spent in writing
    reports, and trying to avoid breaching any childcare guidelines, or worse,
    actual legislation, much of which was at best unnecessary and obstructive,
    and at worst, total euro-nonsense. Eventually, like many independents, she
    gave it up, and sold it to one of the big chains, who now dominate the
    childcare business, and are the only ones who can afford to employ the legal
    people to make sure that they are complying. I can see us independent repair
    agents being driven out of our businesses over the next few years for the
    same reasons ...

    Arfa
     
  11. Eeyore

    Eeyore Guest

    Lead-free solder joints do look grey. And they have poorer resistance to
    vibration induced failure AIUI.

    If you use Sn-Pb solder to repair a board with PB-free you're *breaking the law*
    and Mr Lead Free Man may come along and fine you £5000 !

    Graham
     
  12. Eeyore

    Eeyore Guest

    Zinc ?

    Graham
     
  13. Eeyore

    Eeyore Guest

    Correct. He said 'lead-free'.

    Graham
     
  14. Arfa Daily

    Arfa Daily Guest

    Hi Graham. Agreed on the vibration thing. As far as the 'breaking the law
    bit goes, only if the equipment was " placed on the market " post July 2006.
    Equipment prior to that date *can* be repaired totally legally using any
    type of solder and components you like, *even* if it was originally
    constructed using lead-free and RoHS compliant components ... RoHS
    compliance, and maintenance of that compliance, is not required or
    enforcable on pre-July 2006 equipment.

    Arfa
     
  15. Yes.

    Some connectors and switches have been made using material (brass?) in
    which zinc may migrate from the pin into the solder joint, and form a
    ring of isolating zinc oxide. Using a magnifying glass one can see a
    thin grayish ring on the otherwise perfect solder joint.

    My old Apple Macintosh plus had this problem in the deflection circuit
    where it would lose vertical deflection.

    Resoldering the joint gave it a few more years before it happened
    again.

    I also had a preamp with switches that suffered from this problem.
    Thomas
     
  16. bick

    bick Guest

    Is this a leadfree product??? leadfree does not always look shiny and
    good. older formulations are not as good as todays.
    Hand soldering leadfree is an art form. Untrained workers that used
    lead products does not mean they know what they are doing. Must be
    retrained. I have been in manufacturing for 25 years and with
    leadfree its a bitch.
     
  17. The pillocks that came up with this law obviously know nothing about
    electronics. I call on all servicemen everywhere to defy this stupid
    legislation as it is unworkable. Stock up with with as much leaded
    solder as you can and USE it! Screw the rules, I say.
     
  18. Arfa Daily

    Arfa Daily Guest

    Pillocks indeed. It is an ill-thought-through piece of legislation intended
    to protect the environment from a threat which many of us believe did not
    exist from lead in its solder form, in the first place. It is a typical bit
    of euro-nonsense, but unfortunately, this "save the planet" hysteria, whilst
    being laudable in principle, and absolutely fine if applied with common
    sense, has now taken on almost the mantle of a religion, with green as its
    god, and anyone who goes against it is branded as a worthless heretic.

    There are now euro-zealots in just about every local council, who pursue
    people through the courts for incorrect recycling or 'fly-tipping' for
    putting their garbage bins out on the footpath a day early, or placing stuff
    beside a locked bin at their local recycling centre and any number of other
    ridiculous things that I read about in the papers just about every day. It
    even now has its own name - "eco crime", and the perpetrators are "eco
    criminals".

    So, whilst I agree with you 100%, I'm not sure that I want to become the
    first person to be pursued, persecuted, and ultimately treated to a £5000
    fine, possible prison, and a criminal record, for using the 'wrong type' of
    solder. Like it or not, I guess that we've got to just follow the rules,
    until someone a lot more powerful than us, manages to prove that the whole
    thing is a pile of gonads. Otherwise, one of us is going to finish up like
    that poor greengrocer guy that stood up for his right to sell loose bananas
    to little old ladies, in pounds and ounces, and finished up pursued,
    villified, prosecuted and imprisoned, until the poor sod had a heart attack
    and died. Just this week, his stand has proved that it can be worth it, as
    the euro-crap which was going to force this ban on us totally from 2010, has
    now been dropped. But I for one, don't want to test the dubious strength of
    my heart, from the stress that would inevitably result from taking on these
    people, do you ?

    Arfa
     
  19. Fortunately we now have the power of the internet. Pester the MPs with
    emails. Pester the "Greens" pester anyone you can think of. Email the
    newspapers. Tell everyone that this bloody madness has got to stop. I
    WILL NOT USE LEAD FREE SOLDER. This is not a "green" issue, its an
    electronics reliability issue. All the extra new equipment being
    produced to replace the failed stuff because of crap joints, not to
    mention houses burning down is NOT the way forward. Its time we put
    these legislative bird brains in their place. The revolution starts
    now!
     
  20. Ian Jackson

    Ian Jackson Guest

    It appears that the reason for relenting was because they realised that
    this could affect trade with the USA who, of course, still use the
    imperial system (even if the do get some of the measurements wrong), and
    wouldn't accept things labelled only in metric. It's a long time since
    we had something to thank the Americans for.
    Ian.
    --
     
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