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Soldering Snot

Discussion in 'Electronic Basics' started by Richard Harris, Jan 14, 2005.

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  1. Hi,
    do your pcb's look like some one has sneezed solder all over it when your
    finished soldering it? Is this normal I do I just royaly suck at it? I seem
    to have lots of fun trying to get the solder to stick to the pcb, should I
    use flucks when soldering? Is there any help full information on soldering
    you have for a newbee?

    Also is it possible to burn out PNP and NPN transistors?

    Thanks For Ya Time.

    And I thought making the pcb would be the hard bit.
  2. Andrew Holme

    Andrew Holme Guest

    Are you kidding? Yes, you must use flux. Are you using plumbers'
    solder or what? You should use fine, flux-cored 60/40 solder for
  3. Guest


    If the solder already has flux in its core, you should not need to add

    Are you keeping the soldering tip "tinned"? Keep an ordinary, wetted
    sponge handy, and wipe the tip on it periodically to keep it shiny. If
    it looks dark and dull, it won't make good solder joints.

  4. Not any more...
    No, and yes, in that order. ;>)
    Put the part you want to solder in place. Heat the _joint_, not the
    part or the PCB pad individually. Then apply the (flux-cored) solder so
    that the joint is wetted; if you get snot globs, you applied too much
    solder. And _don't move_ the part until the solder hardens.

    Get some desoldering braid; it's basically pre-fluxed copper braid.
    You lay it on your snot globs, then heat it (on top, not the joint) with
    your iron. It sucks up the excess (you "lead" the solder up the braid).
    If you leave it in place too long, it sucks up too much solder (unless
    you're trying to remove the part, which is what the stuff is actually
    designed for). Takes a little practice to avoid soldering it down, too.
    Pretty much any solderable part. Sounds like you're leaving the iron
    on the joints too long. All you want to do is fuse the solder into the
    joint between the part and the pad, not make everything red-hot.
    Google for soldering +tutorial and pick one you find most readable.
    Soldering is a skill pretty much anyone can learn, not a talent some
    fortunate few are born with. Making a bad joint takes just as long as
    making a good one, so you might as well learn to do it right.

    Mark L. Fergerson
  5. Trobador

    Trobador Guest

    FAQ about Hand Soldering
    FAQ about Flux
    FAQ about Solder Alloys
    Kester Solder Alloy temperatures (great chart for the workbench)
    Reflow temperature profile of 63/37

    search in:
    Google for weller +"better soldering"
    Google for "Apogee Kits Free guide to electronics soldering"
    Google for "soldering for hams"
    The last three were very helpful (as well as the Keester FAQs)
  6. Gordon W

    Gordon W Guest

    Clean the pad and component lead with an eraser until they are bright and
    Don't touch the pad or component lead with your fingers.
    Place the component in position.
    Lay your resin cored solder across the pad and against the component lead
    just enough to cover the pad width.
    Wipe the hot (320°C) iron tip on a damp sponge (the tip must be clean).
    Apply the iron tip to the solder, pad and lead all at the same time.
    The solder will melt and flow to cover the pad and climb the lead in 1 or 2
    seconds max.
    Immediately remove the iron and solder wire.
    You will have the perfect joint.
    Use a chisel/vee shaped tip and select the gauge of solder to suit the pad
    size, 1-2mm maybe.
    The solder should cover the pad and curve upwards to the lead wetting both
    Think water meniscus (sp) If you have a mercury meniscus (round blob) the
    job is not clean enough/too much solder.


  7. Bob Masta

    Bob Masta Guest

    I have some tips on making PC boards at
    One thing that I always do is to tin the entire board before trying
    to install any components. I have tried those "electroless tin
    plating solutions" and found they make a dull coat, not bright and
    shiny like you need for soldering. So I do it the hard way, which
    isn't really all that hard at all for the typical small board: Get
    some liquid resin flux. Polish the etched board with steel wool
    to remove whatever resist you used (I use felt-tip pens), then
    paint it with a thin coat of flux. Then use the side of the soldering
    iron tip with normal resin-core solder and "paint" the traces.
    You can spread the solder out amazingly thin this way, after
    a little practice, and it goes pretty quickly. Watch you don't
    cover over any holes.

    I use rubbing alcohol and an old toothbrush to remove the
    flux. When dried the board looks like it's been chromed.
    Not only is soldering a breeze, but the tinned surface is
    resistant to corrosion without the need for spray coatings.

    Best regards,

    Bob Masta

    D A Q A R T A
    Data AcQuisition And Real-Time Analysis
  8. JeffM

    JeffM Guest

    Thanks for posting a bunch of dead links.
  9. Danny T

    Danny T Guest

    *chuckling out loud*
    I hadn't soldered since school when my PIC Programmer *Kit* arrived a
    few weeks back... I went out and bought a soldering iron (cheapest I
    could find!) and prepared myself to ruin it. Suprisingly, everything
    worked when I plugged it in, and looking at it, it (unbelievably!) looks
    pretty neat... It seems the solder sticks to the rings around each hole
    on the board, and doesn't stick to "the green stuff"... Are you sure
    it's a PCB you're soldering? ;)
  10. Thanks for all your info.

    I tried using the method stated, putingt the iron onto the component lead
    and then touching it with solder for 1 second and my soldering improved by
    about 900%. It now looks great just like the professional manufactured
    board. And now my components do give of smoke. Thanks, you guys are great.
    Hehe, learn to solder in 15 seconds.
  11. Danny T

    Danny T Guest

    I hope you mean "don't"!
  12. Made a typo "Don't give of smoke now". Sorry

    Question : How do surfice mount IC's that have realy fine leads get
    soldered. Is there some kind of special tool that does it or is there simply
    a trick to doing them?

  13. Danny T

    Danny T Guest

    This any good?
  14. Hard to control. You can buy specialized pcbs called 'surfboards' that
    help with SMT breadboarding. They aren't cheap, but for a hobbyist, it
    may be the way to go for those parts that can't be had in DIP.

    Robert Monsen

    "Your Highness, I have no need of this hypothesis."
    - Pierre Laplace (1749-1827), to Napoleon,
    on why his works on celestial mechanics make no mention of God.
  15. Rich Webb

    Rich Webb Guest

    Most parts are still available in through-hole form factors. Some of the
    more recent goodies (e.g., some microcontrollers, CPLDs, FPGAs) are not
    but there are breakout boards. Some examples at

    For soldering large'ish surface mount parts, I've had the best results
    with a "wipe and wick" method. Use a small (but "normal") wedge-shaped
    tip and tack down two opposing corners. Solder bridges are OK at this
    point; what you want to do is ensure the part's leads are centered over
    the pads. Then "wipe" all of the leads on one side with a more or less
    continuous solder bridge. Allow to cool and repeat for the other sides.
    Allow to cool again and then go around the leads using solder wick to
    soak up the excess solder. If you don't put down too much solder to
    begin with, don't try to wick up every last bit (just enough to clear
    the bridges), and inspect it afterwards with a lens, then you can get
    "good enough" results pretty quickly. Not suitable for production work,
    clearly, but OK for the occasional home project.
  16. Trobador

    Trobador Guest

    with little effort:

    poptronics is definetely dead. Sory for that one.

    first Google hit for weller +"better soldering" =
    Results 1 - 10 of about 86 for weller +"better soldering". (0.41

    Google for "Apogee Kits Free guide to electronics soldering" first link:

    Google for "soldering for hams" was not good, but Google for "soldering
    +hams" came out with a bunch, too many to list.

    YOU are allowed to use your imagination and common sense when researching a
    subject. Was I suposed to spoon feed?
  17. JeffM

    JeffM Guest

    Thanks for posting a bunch of dead links.
    Then why bother to post links at all?
    I can read the Subject line. I can use Google on my own.

    This is exactly why the Submit button on Slashdot
    has a label beside it that says *Check those URLs!*

    I hope this isn't the level of work you present to your boss
    then say. "use your imagination".
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