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Trouble with solder

Discussion in 'General Electronics Discussion' started by 8bit, Sep 26, 2015.

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  1. 8bit

    8bit

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    Oct 30, 2013
    I have returned to the project I am working on but found I have problems with my solder. It melts fine but is just not adhering to the joints but instead just sticks to the connections in sticky clumps, not really forming nice smooth connection. Any reasons why this is happening?
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,385
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    Jan 21, 2010
    there are a number of possibilities.

    you are melting the solder but not hearing the joint.

    your wires are very badly corroded.

    there is no flux in your solder.

    your wires do not have the insulation removed.

    your soldering iron does not have the heat capacity or power to heat the joint sufficiently.

    your joint consists of materials that can't be soldered.

    I think that covers most of the options.
     
    8bit and Arouse1973 like this.
  3. 8bit

    8bit

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    Oct 30, 2013
    Wow, thank Steve.

    I can rule out all problems with the solder as I have used it recently. I am connecting two components together without any wires inbetween. As with the solder, the iron has been used recently with no problems so I am a little confused.
     
  4. Alec_t

    Alec_t

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    Jul 7, 2015
    Oily finger marks on the component legs?
    Are you using lead-free solder or leaded?
     
    8bit likes this.
  5. 8bit

    8bit

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    Oct 30, 2013
    Thanks for the reply.

    It's lead free. I can post some images of the results.
     
  6. wingnut

    wingnut

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    Aug 9, 2012
    I dont solder anything without applying flux to both conductors.
    And when the soldering iron is hot, wipe it first quickly with a wet sponge to make it shiny. Add new solder to the hot iron.
     
  7. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    "you are melting the solder but not hearing the joint."

    What is the joint saying ? Heat me ! Heat me ! Heat me !!
     
  8. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    The first thing you must remember is this:

    It's not the solder you want but the FLUX. It is the flux that does all the work. When the flux is heated it is just like a strong ACID. It EATS the scum and compounds and even the oxidization on and around the items you are intending to solder.
    At this point in time the solder PLAYS NO PART.
    You want to heat up all the SCUM and have it "floating" In other words you want it to be DETACHED from all the other components.
    Now the solder can get under the scum and attach itself to the BARE COPPER or cleaned leads of the component or the cleaned tinned surface of the PCB or even nickel plated components
    I see people "carrying the solder" to the joint, on the iron. This is WORTHLESS.
     
    8bit likes this.
  9. Alec_t

    Alec_t

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    Jul 7, 2015
    I've never used the stuff, but it's said to be trickier to get a good joint with that.
     
  10. Old Steve

    Old Steve

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    I used it once, years ago, and found that. It just didn't flow quite as well. I've stuck to good ol' lead solder ever since.
     
  11. Bluejets

    Bluejets

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    Oct 5, 2014
    What are the "two components" what material type , what size, how big (wattage) is your iron?
     
  12. davenn

    davenn Moderator

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    lead free just requires a higher temp. to melt and flow
    All the GPS gear I work on is RoHS and is lead free


    D
     
  13. Old Steve

    Old Steve

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    It worked OK, Dave, but just didn't feel the same. I guess I should be more ecologically aware - I am when it comes to recycling, but as soon as it felt different I gave up. :rolleyes:
    I think that roll of lead-free solder is still here somewhere. I might dig it up and give it another go.
    (Most of the chips that I buy now are RoHS compliant.)
     
  14. Colin Mitchell

    Colin Mitchell

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    You are worrying about the lead in solder and yet buy petrol with lead content and allow diesel cars to run on the roads that emit particles so fine that only recent tests have discovered them.
     
  15. Old Steve

    Old Steve

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    Jul 23, 2015
    Not me - I ride an electric bike. ;)
    And I'm not worried about the lead in solder. That's why I still use leaded solder.
     
  16. davenn

    davenn Moderator

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    Sep 5, 2009
    ?? who were you referring to ??
     
  17. 8bit

    8bit

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    Oct 30, 2013

    Thank again everyone for the replies.

    Wingnut, it is interesting you mention this as I have just read the small guide that came with my iron and it states' ...when using non-rosin-based solder be sure to apply soldering paste to the part before applying solder' I have never heard of this paste or that type of solder. I always assumed you just bought solder, heated it and away you go.(?)

    My iron is a 30w model and the components are to 2N2222 transistors.
     
  18. davenn

    davenn Moderator

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    Sep 5, 2009
    Rosin cored solder is just that , there are several little tubes up the inside of the solder that has the rosin flux in it
    saves the need for adding external flus to the solder job

    Tho, I think you can still buy reels of non-rosin cored solder, its not overly common these days
    But for larger soldering jobs like what plumbers etc would do, where the solder comes in ~ 1.5 ft long bars, 1/2 inch in diameter
    you would have also have a small tin of flux that you would dip the end of the solder bar into then apply to the copper pipe etc and heat up together

    Dave
     
    8bit likes this.
  19. 8bit

    8bit

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    Oct 30, 2013
    I guess I may not be heating the components' leads enough. I am scared of holding the iron on them too long in case of damaging them.(?)
     
    Last edited: Sep 27, 2015
  20. duke37

    duke37

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    Jan 9, 2011
    If everything is clean and there is a slight amount of solder on the iron, you will get the leads up to temperature quickly and then by adding solder to the joint, you will get a good joint in a short time.

    If you need more than a couple of seconds then either the components are not clean or the iron is not hot or big enough. Don't use a pointed iron bit, it may not have sufficient thermal capacity to maintain temperature when applied to the joint.

    P.S. We do not use leaded petrol in the UK except for light piston aircraft.
     
    8bit likes this.
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