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EOL solder wire purchase

Discussion in 'Electronic Design' started by Don Y, Aug 11, 2013.

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  1. Don Y

    Don Y Guest

    Hi,

    Many years ago, I made what I *though* would have been
    my "last buy" of solder wire. Apparently, my estimated
    usage was off -- or, I have lived too long. :< Either
    way, I find myself having to repeat this exercise...
    (the real problem is that I have been using too much of
    it for "bigger jobs" instead of prototype fabrication,
    touch up/rework, etc.)

    [Note I am not worried about solder *paste* -- I buy that
    as needed]

    I figure I will need enough for ~500 (smallish) prototypes
    (several square inches of PCB, components both sides) plus
    miscellaneous wiring, cables, etc.

    And, the sorts of things anyone "electrically/electronically
    inclined" encounters in day-to-day living (repairing
    appliances, TVs, etc.)

    In addition to 0.028" and 0.015" 60/40 wire, recent experience
    suggests I purchase some larger diameter (0.062"?) for those uses
    that eat gobs of wire per connection (i.e., when you'd be
    feeding half a foot just for *one* connection!)

    Suggestions as to how much of which sizes? And, is this truly
    a commodity product (cost being the only issue) or are there
    vendors to avoid/favor? (I've tended towards kester over the
    years -- but for no "real reason")

    Digikey? Or, "anyplace local" (taxes vs. shipping fees)?
    Figure ~$30-40/pound for anything "non-esoteric"?

    Thx,
    --don
     
  2. Joerg

    Joerg Guest

    More like close to fifty bucks for the good stuff. Ouch, ouch.

    And yeah, it's commodity products. Kester makes a leaded no-clean in
    0.062" but personally I haven't used their 8817 yet (well, maybe at
    clients without realizing it):

    http://www.digikey.com/product-search/en?vendor=0&keywords=KE1399-ND
     
  3. Don Y

    Don Y Guest

    Hi Joerg,

    <shrug> Acceptable. It's been *decades* since I last made
    a buy so I'll accept some amount of "inflation".

    Any ideas as to quantities I should target? E.g., figure
    500 densely populated, double-sided boards in the 6-12 sq
    in (per side) range... (they are often much smaller than
    this but usually "stacked" to achieve a particular volume
    profile)
    "No-clean" isn't important -- especially on larger diameters
    (where I might not even *have* to clean up!)

    Thx!
    --don
     
  4. Joerg

    Joerg Guest

    No idea but easy to find out, my wife uses the same trick to find if she
    can make another teddybear from a given amount of yarn of unknown
    length: Weigh your spool of solder on a very precise kitchen scale.
    Solder up a storm, note the achieved square-inches. Now weigh again.

    [...]
     
  5. Robert Baer

    Robert Baer Guest

    Do NOT use "no-clean" as it (1) needs cleaning, and (2) makes for
    more problems than any other formulation.
     
  6. Phil Hobbs

    Phil Hobbs Guest

    AFAICT "no clean" flux for leaded alloys is just good old rosin flux.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC
    Optics, Electro-optics, Photonics, Analog Electronics

    160 North State Road #203
    Briarcliff Manor NY 10510 USA
    +1 845 480 2058

    hobbs at electrooptical dot net
    http://electrooptical.net
     

  7. "Today, one of the most common reasons to remove no-clean fluxes is to
    prevent malfunctions in circuits with clock speeds over 1
    gigahertz. "When you get above 1 gigahertz, the electrons are conducted
    on the outer surface of the conductor," says Stach. "If there's flux on
    the conductors, it can act as a conductor, too, and interfere with the
    signal.""
     
  8. Joerg

    Joerg Guest

    I have never seen that happen and some of my RF and digital designs run
    transitions in the few hundred picoseconds. No problems. I assume what
    they mean with "conductor" is a trace. Those are supposed to be covered
    with solder mask and I don't see how flux can get underneath there.

    Yeah, no-clean is a bit hygroscopic but other than that I haven't had
    problems with it. It's been many years now.

    [...]
     
  9. newark is a good place for solder.
     
  10. Joerg

    Joerg Guest


    Even if it would stick it doesn't matter too much.

    I have seen that with other fluxes, including some weird electrolytic
    effect. A client even saw it depelop some "whitish pus" between to IC
    pins. Never seen that with no-clean but, of course, if you have a very
    high impedance pads close to other conducting matter you have to even
    clean the no-clean. Which is harder to do than with other resin so this
    may be a situation where no-clean is not the best option.

    That's one reason I use no-clean. I just donated a scope to a school and
    first I had to spend many hours repairing it. Turns out the mfg had not
    cleaned the flux. What a mess.

    I always urge clients not to use wave-solder but use reflow instead. It
    prevents a lot of problems from happening.

    Yes, but that also requires measures to be taken at the layout step. Got
    to be really careful with the solder mask. Sometimes we've even added
    silk screen there to make things thicker or build "dams".
     
  11. I can maybe believe a capacitance change if there is moisture absorbing
    crud between pads say. Or leakage in very high impedance circuits as
    Joerg says. But that is not at all what the article was suggesting
    AIUI.
     
  12. Don Y

    Don Y Guest

    Hi Joerg,

    D'oh! Yes, great idea! I'll just have to find a precision scale
    (I don't use scales in the kitchen).

    Thx!
    --don
     
  13. Joerg

    Joerg Guest

    Many postage scales are very precise, even cheaper ones. Like mine which
    was cheap but measures down to one gram in metric mode. Otherwise ask a
    neighbor who is a gourmet cook. They usually have very fancy scales.
    Marble tray, smoked-glass floating see-through LCD on a gold-plated
    metal post, the works. We've got one but only because of a liquidation
    sale at a store.

    McGyver method: Put a thin long plank on a pipe, making a see-saw. Mark
    center. Place a rock at one end and the fresh spool on the other so you
    have equilibrium. Now you know what 0.5lbs is. Mark distances from pipe.
    Solder. Place spool on the plank again, scoot until equilibrium. Mark
    new distance, determine with tape measure, calculate weight.

    I bet the local Fedex depot or post office will also be friendly enough
    to perform a quick before-after weighing.
     
  14. Don Y

    Don Y Guest

    Hi Joerg,

    Mine is intended for packages. I think ~40lbs at 0.1oz (maybe 0.2?)
    resolution (I would have to check to be sure -- I keep it packed away
    until needed, like most things, here)
    I had a "precision balance" many years ago (e.g., the sort of thing
    you would encounter in a pharmaceutical laboratory for measuring
    actives and excipients -- like measuring the weight of individual
    grains of sugar!). But, it was *big* (i.e., takes a lot of space
    for the seldom used functionality it affords) so it was abandoned
    on one of the moves. <shrug> I've not missed it...

    (lab scales also tend to raise eyebrows with law enforcement
    professionals... best not to go there! :< )
    Post office would probably work. I think they have a scale in the
    lobby. I would *hope* it can handle ~1 lb (smallish... no doubt
    intended for *letters*). I will check next time I find myself
    there (seldom). If I *know* I'll be there, I can bring a spool
    of solder wire with me and see if it "notices" several inches
    removed between weighings...
     
  15. Jeroen

    Jeroen Guest

    In the land of the free! What are you coming to?

    Jeroen Belleman
     
  16. I bought some ebay "precision scales", quite cheap, did not pay much
    attention to what I was buying. I had some idea I would use them to
    count components, nuts or something. Claimed up to 0.01g resolution I
    think.

    I was puzzled to get a CD in the post. I realise it is the weigh
    scale. Designed to look like a CD! WTF. They are built into a CD case,
    clearly designed so as to look innocent to visiting law enforcement!

    I expect I am on a List now...
     
  17. Joerg

    Joerg Guest

    .... until just about now :)

    I could care less. They aren't going to tell me what I can use. A
    pharmacists also raised a brow when I wanted syringes. "For oiling in
    tough spots" ... "Ah, ok".

    It will. Even the li'l post office in our town which is in a corner of a
    Bel Air supermarket has a scale that measures minute quantities, yet
    goes up to several pounds. But I am sure a neighbor has an electronic
    kitchen scale.
     
  18. sms

    sms Guest

    I'd just get Kester 63/37 in several sizes. The savings in buying a
    no-name solder are minimal. Check craigslist too. In my area someone is
    selling new rolls of Kester 63/37 solder for $15/pound in 0.015 and
    0.062 diameters.

    For large jobs I'm still working on a 5 pound roll I bought at the
    Atlanta Hamfest in 1977.
     
  19. Joerg

    Joerg Guest

    sms wrote:

    [...]

    Careful. Those probably vanished at a local business. Or fell of a truck.

    It happened over in Europe where someone was selling antennas at a very
    good price, better than wholesale. IIRC he was arrested later.

    [...]
     
  20. tm

    tm Guest

    Not lab scale, a reloading scale. :)
     
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