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Soldering newbie

Discussion in 'Electronic Basics' started by M. Hamed, Apr 3, 2013.

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  1. M. Hamed

    M. Hamed Guest

    I am not new to soldering. I have some soldering experience. I have built aradio kit with no soldering problems whatsoever. I have made little boardsfor things like transistor amplifiers for my crystal radio. I have little surface mount experience, but in a moment of extreme courage, my boss let me rework about 50 PCBs at once when he was on vacation. That involved soldering a little SMT cap using tiny little wire to a nearby IC pin. Most of the boards worked, but the job looked horribly ugly.

    The reason I consider myself still a newbie, is that successes are not always repeatable, and failures are not always avoidable.

    I have read numerous guides on the Internet but some things really don't click. I thought I could start this thread to ask questions that will probably be obvious to some but still not very clear to me.

    The questions at hand for now are these:

    1) Soldering guides always recommend you to tin the tip of your iron with fresh solder before starting on a joint. Every time I do this the solder burns and discolors. Is that normal or am I doing something wrong? Do I have to be really fast before solder burns?

    2) Soldering guides tell you to always heat the joint not the solder. Whenever I do this, it seems it takes forever for solder to melt. It also seems that the pointy part of the tip (as they always show in drawings) isn't really hot enough I have to find a sweet spot on the tip that is hot enough and then touch it to the wire. Do I just have a bad iron?

    3) Can I use copper wool instead of a wet sponge? I have been using it recently with success. The problem is that I'm not sure if it's better than a sponge or not. I'm not even sure of the function of the copper or the sponge.. I know it's for wiping the tip clean but it's hard for me to gauge how much better cleaning the tip actually provides.

    4) When to use flux and when is it not important? I soldered the transistorradio kit completely without flux. But also the type of solder they provided with the kit seemed really good, I thought may be the solder has it all.


    I know this has been answered a million times before but if someone is feeling bored may be they can share their experience. I know I probably can spend hours scouring internet forums and getting all sorts of conflicting information. I thought I may get some direct answers here! THANKS.
     
  2. Phil Allison

    Phil Allison Guest

    "M. Hamed"


    1) Soldering guides always recommend you to tin the tip of your iron with
    fresh solder before starting on a joint. Every time I do this the solder
    burns and discolors.

    ** The iron is too hot, get an adjustable or temp controlled one.

    It is possible to use a light dimmer with a cheap iron to reduce the temp.


    2) Soldering guides tell you to always heat the joint not the solder.
    Whenever I do this, it seems it takes forever for solder to melt.

    ** When you touch the tip against a joint, immediately apply a little solder
    to tip so the hot solder carries the heat around.

    It also seems that the pointy part of the tip (as they always show in
    drawings) isn't really hot enough I have to find a sweet spot on the tip
    that is hot enough and then touch it to the wire. Do I just have a bad iron?

    3) Can I use copper wool instead of a wet sponge?

    ** Brass wool is best.


    4) When to use flux and when is it not important? I soldered the transistor
    radio kit completely without flux. But also the type of solder they provided
    with the kit seemed really good, I thought may be the solder has it all.


    ** Use only flux cored, 60:40 tin lead solder for electronics.

    Avoid the lead free kind.



    .... Phil
     
  3. If the iron wasn't tinned right at the beginning, then the tip gains some
    coating that causes the solder to just roll off.

    I have a vague memory of this happening once, but I can't remember what I
    did. I do know that when you have properly tinned the tip from the
    beginning, some residue can build up, and you need to work at clearing
    that up so the solder doesn't ball and roll off when heated, but spreads
    out over the tip.

    I also have a vague memory of burning solder on one iron, yet it seems
    more related to an untinned tip. Because it's not like I've bought
    endless packs of solder over the years, and the same solder works fine on
    my soldering gun, which is much hotter than the irons I've had in forty
    years. I think maybe I ended up with some bad solder, or solder rated at
    a lower temperature. But it's been decades.
    The guides all say that, but most people do melt some solder on the tip as
    it is held against the joint. The melted solder helps the heat to flow.
    Once there is a bit of solder on the joint, the heat flows more easily.
    No. Except really cheap irons (the tips will last a very short time),
    soldering iron tips have been plated for decades. If you use something
    metallic to clean it, you may clear off the plating. The plating is a
    great thing, it protects the tip. Without it, the tip will decay after a
    relatively short time, while all the plated tips I've had last forever.

    You don't want a lot of solder on a tip, at least when you are soldering,
    yet keeping some solder on the tip protects it. So you pull your iron out
    of the stand, briefly wipe it on the sponge (paper towels work too, I
    don't even bother dampening them) before you solder, and then before you
    put the iron back in the stand (at least if it will be sitting there for a
    while), add a bit more solder.

    So it's primarily to get the excess solder off, something you don't need
    steel or copper wool for.

    There are times when there's sort of a carbon buildup, I guess solder left
    on the tip too long without being wiped off, and that takes some work to
    clear off, but no actual filing or need for steel wool. But the build up
    happens because the excess solder isn't regularly wiped off.

    That said, again if you don't tin the tip properly at the start, there
    will be later problems.
    The solder has flux built in. Melting a bit of solder on the tip of the
    iron helps to spread the flux onto the joint you are trying to solder.
    Same thing happens with old solder, the flux has long gone, you try really
    hard to heat up the joint but no success. Melt a bit of solder against
    the iron on the joint, and the new solder provides flux for the heat to
    flow, so the old solder melts like it should.


    Michael
     
  4. Bill Bowden

    Bill Bowden Guest


    Another trick is to coat both surfaces with solder before joining them
    together and clean the surface of the leads. So, if you want to solder
    two resistor leads together, use an exacto knife to scrape the
    resistor leads clean and then apply a thin coat of solder to each
    lead. Then put the resistor leads together and solder the joint. You
    may not need any solder on the iron, just heat the leads and they will
    melt together..

    -BIll
     
  5. Phil Allison

    Phil Allison Guest

    "Bill Bowden"

    Another trick is to coat both surfaces with solder before joining them
    together and clean the surface of the leads. So, if you want to solder
    two resistor leads together, use an exacto knife to scrape the
    resistor leads clean ...

    ** You should never have to do that.

    Only very old and badly corroded leads require scraping.


    ..... Phil
     
  6. Phil Allison

    Phil Allison Guest

    "M. Hamed"

    I know this has been answered a million times before but if someone is
    feeling bored may be they can share their experience. I know I probably can
    spend hours scouring internet forums and getting all sorts of conflicting
    information. I thought I may get some direct answers here!


    ** There are two common reasons why beginners have problems soldering:

    1. They are using a shit awful soldering iron.

    2. They are using lead free or flux free solder.

    Hamed, like most, has not revealed what HE is using.



    ..... Phil
     
  7. notbob

    notbob Guest

    No kidding. Metcals are insanely overpriced, even if they now have a
    station in the mid $200 range. Jes get a Hakko FX888. You can get
    'em fer < $85 and they have a great range of tips, even down into SMT
    sizes.

    nb
     
  8. M. Hamed

    M. Hamed Guest

    Thanks for all the help.

    Yes, it is brownish with some blue. You're right it's most likely the flux.
    I do have a temperature controlled station. I looked last night at the temperature setting and it was about 750-800.
    So do I need to clean every time before applying solder?
    Yes, I am realizing now my sponge had too much water. I tried the scotch bright cleaning sponges but I didn't know they had extra chemicals on them. Ihad a hard time finding one that doesn't have stuff added. The one that came with the soldering station is in a bad shape.

    I see the experts at work use flux all the time. My guess is that it's needed for 1-Lead free soldering, 2-Surface mount components with very small pitch?

    This is more or less what I used to do and solder seemed to melt easier this way. However I read in many places where they tell you this is a big NO NO.

    But even with tinning the burnt flux still coats the tip. I will retry reducing the temp as everyone is suggesting.
    Oh, Thank you! That was my experience too. I always felt guilty about it though :)
    So you're saying tinning should be done after soldering the joint, not before? Could you describe how you typically tin the tip? Just touching it to the solder wire seems to concentrate solder on one side of the tip. If I wipe it with the sponge, I don't know if it stays there or not.

    Phil, I do not use lead free, except if I have to do some soldering at work.. Mainly when the job is too easy it is embarrassing to send to the tech. Iuse leaded solder with my home projects (which haven't been so many).

    Rich, I have this: http://www.circuitspecialists.com/csi-station1a.html
     
  9. Phil Allison

    Phil Allison Guest

    "M. Hamed"
    This is more or less what I used to do and solder seemed to melt easier this
    way. However I read in many places where they tell you this is a big NO NO.


    ** I have just seen a site where the writer gives this and other WRONG
    advice too.

    It is a common mistake to apply solder to the tip and then carry it to the
    joint - but that is NOT my advice.

    The idea is to AID the tip in heating the joint FAST by *re-tinning* it as
    you go.

    So, after applying the tip, add a dab of solder - then as the solder flows
    around add a more to the joint itself.

    Good soldering is done very quickly, blink and you will miss it.

    A slow motion, close up vid would be good.



    .... Phil
     
  10. Phil Allison

    Phil Allison Guest

    "Phil Allison"

    ** This one will do nicely....




    .... Phil
     
  11. Phil Allison

    Phil Allison Guest

    "Phil Allison"


    ** You may have to copy and paste the link into YouTube.



    ..... Phil
     
  12. Bill Bowden

    Bill Bowden Guest

    Remember the old wire-wrap boards? No solder, just simply twist the
    wire around the square post and the sharp edges made a gas-dry joint.
    I know a guy who sells glue and does an impressive demo at the swap
    meets. He glues rubber, glass and metal in seconds and claims you can
    twist two wires together and just use his glue without any solder. I'd
    like to try some of it, but he sells the stuff for $20 an ounce. But
    it is amazing.

    -Bill
     
  13. Guest

    You clearly had incompetent people running the show. If properly
    done, WireWrap is as (or more), reliable as soldered connections and
    you don't daisy-chain the stuff. You should never have to pull more
    than three wires to replace one. At one time mainframes were all
    WireWrapped (millions of connections) and were *quite* reliable.
    Three-high was a no-no, as well, though that was probably for other
    reasons (impedance). The pins were shorter than some, designed for
    two wraps only (but a third was easily possible).
     
  14. I suspect that's some of the issue, the commercial stuff was the mainstay
    of wire wrap. I've never heard of much trouble with commercial stuff,
    which may mean it was outside the hobbyist realm, or it may mean it works
    fine.

    Certainly when it hit the hobbyists, about the time Byte arrived, it was
    treated as a serious thing, so surely the example of commercial wire
    wrappted equipment was there.

    But once in the hobby world, it likely wasn't the same thing. Yes, you
    could buy actual guns, but for many it was done manually, which I can see
    would be a source of trouble. Also, those who hadn't had experience
    likely had problems, just like the person beginning to solder doesn't yet
    have the experience to know they have bad joints.

    I suspect many didn't grasp the concept, and indeed we saw a lot of
    intermediate work, wire wrap sockets and wire wrap wire, but a cursory
    wrap around the socket pin and then solder, as if people didn't trust the
    notion of wire wrapping. I admit that as someone who had already been
    soldering, the notion of just twisting the wire around the socket pin
    didnt' seem secure.

    Michael
     
  15. Guest

    Unlike most hobbyists, it has to be wrapped tightly. ;-) Seriously,
    that's the major problem, getting enough tension on the wire as it's
    being pulled around the post so the wire bites into the edges. The
    other major problem I saw was stripping. Many would nick the wire.
    Bad news for reliability. We had special strippers that looked like
    long-nosed pliers with a nick in the jaw (not the blade). Some didn't
    know that they were special tools and would use them as long-nose
    pliers. One turn of a nut and they were shot. At $100 each, people
    got a little protective of their tools.

    I wouldn't have expected that it was as good as it was, either. It
    does take some skill, then so does soldering.
     
  16. Guest

    I did that for manual wrap, though used a file (then spreadsheet) for
    technician use. They then would put in every other wire in a net,
    finally adding the ones in between. That way, if something changed
    (or broke), one didn't have to rip the whole net out.
    I used to do that with PCB netlists. Tools have gotten much better,
    though. It's amazing the errors that can be seen by the eye without
    looking at the actual data.
    Unless order made a difference.
    Yep. Our techs did that by doing every other wire in a net, then
    coming back and fill in the 2nd levels.
    I prefer it to dead bug, though it's expensive. I used to have some
    pretty complicated WW boards (one with >6000 wires - memory busses
    nave lots of wires ;), before PCBs got cheap.
     
  17. Jasen Betts

    Jasen Betts Guest

    take some wires, take home a sample glued joint?
     
  18. Bill Bowden

    Bill Bowden Guest

    Yes, it could be a problem. I remember a case where we had an
    inexperienced person doing a R&D wire-wrap job with little
    supervision. Turned out there was a short from +5 to ground, so we
    decided to apply a small current from a PS to see if the offending
    wire would get hot and reveal itself. We cranked up the PS to about 20
    amps and nothing got hot, so we had to throw away the whole board
    since there were too many shorts across the PS.

    -Bill
     
  19. You need a chisel tip instead of that 'pointy' tip.

    The point of a conical tip never makes enough contact.
     
  20. Phil Allison

    Phil Allison Guest

    "Tom Del Rosso"

    This vid ( I posted earlier) shows how to use a pointy tip to solder
    regular components like 1 amp diodes to a PCB with plated through holes.



    The side of the tip is used and solder is constantly re-applied to the tip.



    ..... Phil
     
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