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Tools for desoldering?

Discussion in 'Electronic Basics' started by Hamad bin Turki al Salami, Dec 22, 2006.

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  1. I'm not very skilled with soldering but I have a bunch of components
    I need to replace. I have a solder pump and copper wick. I can get
    the job done with these, but it's slow work. Maybe with more practice
    I'd improve, but as it stands, I end up using the pump 3 or 4 or
    more times before I get most of the solder up. I'm not too successful
    with the wick at all.

    So I'm considering buying something fancier. I'm willing to spend
    $100 or so, perhaps more if something is really highly recommended.

    All suggestions appreciated.
     
  2. Eeyore

    Eeyore Guest

    Where's it going wrong ? I can manage with a pump and wick just fine but
    technique is everything. The quality of the wick varies hugely too ! As do pumps
    in fact, come to think of it.

    Give us some more details.

    Graham
     
  3. Andrew Holme

    Andrew Holme Guest

    I prefer wick.

    Sometimes it helps to apply fresh solder first, to get things flowing, and
    then apply the wick.

    I presume you are placing the wick between the soldering iron and the joint?

    Are you using "no-clean" wick? I prefer the full-fat variety. You can
    often tell from the colour of the reel. No-clean is usually green. The red
    reels have more flux.

    Are you desoldering SMD or through-hole?
     
  4. Chris

    Chris Guest

    Hi, Hamad. Possibly your desoldering pump is worn out, broken, or
    hasn't been cleaned properly.

    I'm assuming you've got something like this:

    http://rocky.digikey.com/WebLib/OK International/Web Photo/DP-100.jpg

    If you're doing through hole work, they're invaluable because they're
    much quicker (and a lot less expensive) than solder wick. I just grab
    the solder with the pump, one click, and I'm done. Since they're
    faster than wick, there's less chance of cooking the part if you might
    want to reuse it. For SMT parts, though, they're generally not too
    useful, because they'll just suck up the part along with the solder.

    You don't always get what you pay for, but you'll always pay for what
    you get with these. Better quality manual desoldering pumps have
    better rings and seals and higher quality teflon nozzles which won't
    melt or deform under heat. Try an aggressive cleaning of the pump,
    paying close attention to the seals and rings. Also, replace the tip
    if it's deformed and a replacement tip is available. You can't get
    good suction if you're not on the solder joint. If that doesn't work,
    then replace the thing.

    Although they're very useful for fine work, the expensive setups are
    probably overkill for most basic work. Just try getting a good basic
    tool, and go with that.

    Good luck
    Chris
     
  5. Eeyore

    Eeyore Guest

    That often helps.

    Me too. It's all about introducing some more flux into the area.

    That's manufacturer dependent. The best wick I've ever used btw is 'Soder Wick'
    (tm).

    Wick and pumps have slightly different applicability too.

    Graham
     
  6. Eeyore

    Eeyore Guest

    You can get service parts for them.

    The seals and nozzles wear out quite quickly and *have* to be replaced
    periodically.

    Never *ever* clean the solder slag off the 'prong' of a pump with a pair of
    serrated pliers btw. It'll totally wreck it.


    Graham
     
  7. DJ Delorie

    DJ Delorie Guest

    This is way over $100, but for removing SMD parts I really like the
    way the Metcal Talon works. Like others said, sometimes you have to
    add solder to get good heat connectivity, but at least with the Talon
    you just grab the part and remove it. I've used it for some
    through-hole parts too, if the leads are arranged such that the tips
    can melt them all at once.

    With a regular iron, one trick that sometimes works is to add more
    solder such that all the pins bridge. Then you can sometimes melt
    them all at once and lift that side of the part up.
     
  8. One thing that I find helps a lot if I don't have to recover the parts
    intact, is to just just cut the leads of the through hole components in
    need to replace so you only have to work with one pin at a time. I then
    heat the remaining leads with my soldering iron and remove them with
    needle nose pliers. The last step is to mount the board in a vise, heat
    one side with the soldering iron and suck the solder out the other side.
    I find this method gives you nice clean holes and minimizes board
    damage. One thing that you want to be careful of when using a hand held
    solder pump is to hold the tip steady when you trip the pump. If you
    allow the tip to slide across the boare, you risk damaging the solder
    pad on the board, particulary if you have to apply a lot of heat to get
    the solder to melt on both sided of a multi-layer board.

    If this is something you'll be doing a lot, then you ought to consider
    buying a temperature controlled desoldering station. I personally
    prefer Hakko's stations, but there are others. Unfortunately, one of
    those is quite a bit more than your $100 budget even if you are patient
    and buy it off eBay. If you go this way, make sure you get one with a
    built-in vacuum pump unless you have shop air available.

    Hakko does have a hand-held desoldering tool that heats and generates
    it's own vacuum. I've seen it offered by eBay sellers for $165 or so.
    I haven't used one so I can't comment on how easy they are to use but
    you might ask for input from others.

    Good luck.
     
  9. Bob Masta

    Bob Masta Guest

    <snip>

    For completeness (and more divergent from the OP's
    question), sometimes you may need to do the opposite
    of the above, and recover parts from a board that is
    to be scrapped. Many years ago I hit upon (literally!)
    a quick-and-dirty approach that needs no special
    tools... just a work surface you don't care too much
    about. You heat up each solder pad, then *WHACK*
    the board sharply against the workbench, solder pad
    down. Inertia removes the solder as a nice splash spot
    on your bench, but it doesn't actually hurt anything and
    can usually be peeled right off. (Of course, you can
    always use a protective layer of scrap wood or something.)
    Do this for each pin, then wiggle it a little with the needle nose
    to make sure it's free.

    I rescued lots of "too good to toss" stuff from the scrap bin
    of my employer back in the '70s. Ahh, the good old days!

    Best regards,


    Bob Masta
    dqatechATdaqartaDOTcom

    D A Q A R T A
    Data AcQuisition And Real-Time Analysis
    www.daqarta.com
    Home of DaqGen, the FREEWARE signal generator
     
  10. Arlet

    Arlet Guest

    You can also heat bigger section of the board over a gas range, or by
    waving a blow torch or paint stripper over the board, then whack it
    component side down. With a bit of luck the entire component will come
    out cleanly. I've done this once to remove a 40 pin connector from a
    scrap board.
     

  11. That kind of impact isn't good for some parts, like crystals.
     
  12. Rich Grise

    Rich Grise Guest


    How's ten bucks?
    http://www.radioshack.com/sm-45-watt-desoldering-iron--pi-2062731.html

    The tips are replaceable and cheap, but you do have to clean it out
    pretty often.

    Have Fun!
    Rich
     
  13. Rich Grise

    Rich Grise Guest

    For about three decades now, I've been saying, "gotta get me a little
    vacuum pump and trigger switch..." The ones with the electric pump are
    much nicer, but cost 10-20 times as much. ;-)

    Cheers!
    Rich
     
  14. Jamie

    Jamie Guest

    I've got a pile of those new in the package. I seems over time, every
    time went to Radio Shaft, I could never remember if i had a spare unit
    so i would some times buy one those and maybe one 15 and 30 iron..
    One day i decided to clean up, after throwing away a lot of junk. I
    now have aprox 8 desolder units like that from radio shaft and about 12
    or various irons all new in packages.
    I stopped buying those things when i got my high end
    solder/desoldering station. I save those for portable use now :)
     
  15. Ross Herbert

    Ross Herbert Guest


    The OK Tools Soldapult is definitely the best tool for removing solder
    from most components but often it is necessary to make several
    attempts along with added flux and/or solder, especially for IC's or
    multi-pinned items.

    Many pcb designers err towards the smallest through-holes necessary
    for component mounting, even when it comes to low density designs.
    They seem to completely ignore (perhaps deliberately in some cases)
    the problems they create for board level repairs by not leaving
    sufficient clearance around the component lead through-hole. When it
    comes to desoldering, the closer the component lead is to the plated
    through-hole, the more difficut it is to remove all solder. In some
    cases I have been defeated even when using a Hakko 474 vacuum
    desoldering tool.
    http://www.hakko.com/english/products/hakko_474.html

    Because you can't move the lead sufficiently far enough from the side
    of the hole some minute solder wicking remains. On IC's with many pins
    you only need this to happen on several pins to make it very difficult
    to remove the component without damaging the through-holes. (PCB
    designers please note)

    I am currently in the process of salvaging components from an 80's
    vintage Sagem teleprinter and I truly thank the board designers for
    making the through holes extremely generous. Every component has been
    easy to remove without any damage. The only problem is that the leads
    have been bent almost flat on the solder side but judicious side
    pressure with the desoldering tip usually gets them upright again.
    Unfortunately this isn't so easy with a standard soldering iron and
    manual solder sucker (OK Soldapult).
     
  16. Rich Grise

    Rich Grise Guest

    Well, clearly the vacuum station is the best bet - I've found that
    giving the pin a little wiggle lets all of the solder loose, and
    if you continue to wiggle it as it cools, the chip will just fall out.
    (the inrush of room air cools the joint).

    But, when you don't have a vacuum station, I've found that the Solder
    Sucker trick works _most_ of the time; sometimes I've had to follow
    up with wick, sometimes from both sides of the board.

    With SMT, of course, this is all moot. :)

    Cheers!
    Rich
     
  17. Ross Herbert

    Ross Herbert Guest

    That is the correct technique but it isn't that simple if there is no
    room in the hole to wriggle the lead. Round pins are especially
    problematic in too-small holes. Also, even with ALL solder removed
    from around IC pins you will inevitably find that minute traces will
    remain on the top side of the board at the pin shoulders where no air
    flow can penetrate. Providing that the pcb is made by a reputable
    maker and through-hole plating is reliable, gentle upward leverage at
    each corner will break these minute bonds without doing any damage. I
    have found some cheap boards where part of the through-hole will come
    out still stuck to the pin. This problem is exacerbated when trying to
    remove turned-pin IC sockets (not done very often) because these have
    shoulders which remain in contact with the top plating a full 360
    degrees, whereas IC pin shoulders only make contact at two points.
     
  18. Rich Grise

    Rich Grise Guest

    Yabbut, the reason to use sockets is so you don't _have_ to unsolder
    anything! :)

    Cheers!
    Rich
     

  19. I heat the pin with the end of a soldering iron tip, and as soon as
    it melts enough to break the bond I let go. It works almost every time.
    If you apply the heat too long, it will reflow and bond the pin back to
    the PTH.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
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