Basic Soldering Quesiton

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  • obscurehero
    Member
    • Jan 2011
    • 26

    #1

    Basic Soldering Quesiton

    So, I recently re-capped a few problem capacitors on an old LCD monitor. I had bought all the capacitors to re-cap the whole board, just to be safe, but stuck with the problem capacitors because of a soldering issue.

    So, when I go to solder, I'll wash the tip on a wet sponge, and it's all nice and shiny. Then after I tin the tip briefly with some solder, the whole outer surface of the iron will turn a brownish/yellowish/blackish color as if its burning something in the air or oxidizing something. Then, those brownish flecks ended up making it into two of my solder joints. They didn't end up hurting the joint, but they didn't look nearly as pretty as the other 4 joints I made.

    Is there a way to avoid getting that brownish crap? Is it just a matter of soldering quickly after cleaning the tip? If its' just a speed thing, then I totally understand why i messed that up.

    Just so you know, I was using the CHIP-QUIK kit to de-solder the caps. I sucked most of the solder away with a de-solder pump, and then used de-soldering braid to get the solder that was left. I cleaned the joint with an IPA pad, and then soldered then new cap on.

    All the soldering was done, actually, in a clean un-used chemical fume hood at my place of work. I figured that environment would limit my smelling the solder fumes and have the least 'dust' or particulates in the air to get into my work.
  • Uranium-235
    Comrade Glimmer
    • Aug 2007
    • 5042
    • US

    #2
    Re: Basic Soldering Quesiton

    that black stuff is usually the resin in resin core solder, its ok, if what you're talking about is what I think you are
    Cap Datasheet Depot: http://www.paullinebarger.net/DS/
    ^If you have datasheets not listed PM me

    Comment

    • obscurehero
      Member
      • Jan 2011
      • 26

      #3
      Re: Basic Soldering Quesiton

      So, how do you limit the black stuff? Buy non-rosin core solder?

      Comment

      • retiredcaps
        Badcaps Legend
        • Apr 2010
        • 9271

        #4
        Re: Basic Soldering Quesiton

        Best soldering video is by CuriousInventor at

        http://www.youtube.com/watch?v=I_NU2ruzyc4

        And you don't need Chip-Quik for basic electrolytic caps. CuriousInventor also talks about Chip-Quik in another video here

        http://www.youtube.com/watch?v=FTQqjggeklo

        Of course, this site also has an excellent written soldering tutorial at

        https://www.badcaps.net/forum/showthread.php?t=485
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        Comment

        • obscurehero
          Member
          • Jan 2011
          • 26

          #5
          Re: Basic Soldering Quesiton

          I definitely used those resources previously, as someone suggested to me, and they were very helpful.

          My question is just in regard to the dark flecks that get into the solder joint on occasion. Seemed to be, like I described, that the iron would be nice and clean after wiping it on the wet sponge, but w/ or w/o the tinning the iron would quickly darken if not used promptly.

          Comment

          • momaka
            master hoarder
            • May 2008
            • 12170
            • Bulgaria

            #6
            Re: Basic Soldering Quesiton

            Originally posted by obscurehero
            So, when I go to solder, I'll wash the tip on a wet sponge, and it's all nice and shiny. Then after I tin the tip briefly with some solder, the whole outer surface of the iron will turn a brownish/yellowish/blackish color as if its burning something in the air or oxidizing something.
            That's resin/flux from the solder. Don't worry about it.

            What the resin/flux actually does is it "cleans" the surface where the solder is to be applied so then the solder can actually "stick" to that surface. If you used solder with no resin core, you would get very bad, dry-looking solder joints.
            The only way you can use a solder with no resin core is if you used liquid or paste flux. What you do then is you apply a coat of liquid/paste flux on the joints to be soldered, then you put solder on the joints. It still works out the same as rosin core solder, though.

            Comment

            • Agent24
              I see dead caps
              • Oct 2007
              • 4950
              • New Zealand

              #7
              Re: Basic Soldering Quesiton

              I don't usually notice flakes of black junk when soldering..

              What brand is your solder? Maybe you have some cheap one that uses substandard flux?

              Either way, you clean clean the flux etc off with flux remover, isopropyl alcohol etc (you should do this anyway)
              "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
              -David VanHorn

              Comment

              • severach
                Badcaps Legend
                • Aug 2007
                • 1055
                • USA

                #8
                Re: Basic Soldering Quesiton

                The black flakes is the rosin after it's been heated for a long time. As you get better you need less heat and time to do the same work and the rosin won't burn to black flakes any more.
                sig files are for morons

                Comment

                • Agent24
                  I see dead caps
                  • Oct 2007
                  • 4950
                  • New Zealand

                  #9
                  Re: Basic Soldering Quesiton

                  Oh right... that must explain why I don't remember seeing it really
                  "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                  -David VanHorn

                  Comment

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