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I am struggling with soldering some pretty think gold plated DIA pins to one of my boards.

the pins I'm referring to

I've tried various things such as;

  1. Increasing the heat of my soldering iron, but am afraid of burning my board.
  2. Sand off some of the gold plating to try and make the connection easier.
  3. Increase the amount of flux I use.
  4. Increase the time I'm heating the pin/board.

None of the above have given me favorable results. I'm hoping some of you here can steer me in the right direction.

I think I might be too careful and need to heat the pins/connection much more due to the heat dissipation of the thick pins, but before I do that and break things I want to check with some of you.

Thank you very much, I appreciate any responses.

Rik Roukens
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    What soldering iron are you using? Doing this with a 20 W unregulated (no temperature control) iron with a small tip: no go. Doing this with an 80 W temperature controlled iron with a wide tip (large thermal mass): easy. You want to solder this quickly so you need a **large thermal mass** so that the pin and PCB heats up quickly without the temperature dropping below the melting point of your solder. – Bimpelrekkie Mar 11 '20 at 09:59
  • Keep in mind that unless the gold plating is very thin, 10-20 microns or less, then it is not recommended to solder directly to gold. – SteveSh Mar 11 '20 at 10:35
  • You can also try heating up the entire board before doing the soldering. This is what's done in mass production solder reflow operations. – SteveSh Mar 11 '20 at 10:37
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    "Sand off some of the gold plating to try and make the connection easier", well the gold is the easiest to solder. Those are contacts are for use with a mating connector. – Marko Buršič Mar 11 '20 at 10:48
  • @Bimpelrekkie Thanks for your response, I'm using a Hakko FX-888D which is a temp regulated 70W soldering Iron, I have a big tip on the end. – Rik Roukens Mar 11 '20 at 11:00
  • @SteveSh Thanks, much appreciated! I'll give this a shot. – Rik Roukens Mar 11 '20 at 11:01
  • @MarkoBuršič Thank I'll keep that in mind for my next try. – Rik Roukens Mar 11 '20 at 11:02
  • @MarkoBuršič You fell for a common misconception. While gold enables easy wetting it frequently destroys the solder mechanism by bringing your alloy out of the eutectic. Reliable soldering joints can only be achieved by de-golding the surfaces in advance. – Ariser Mar 11 '20 at 17:36
  • @Ariser-reinstateMonica Interesting, but ENIG finish on PCB is still the best and the most expensive, I haven't heard that it could cause problems when soldering, could you explain. – Marko Buršič Mar 12 '20 at 08:11
  • ENIG finish may increase shelf life of PCBs. However gold reduces lifetime of any SAC or SnPb connection, and is inacceptable in high reliability applications like aerospace, mil and medical equipment. https://www.dfrsolutions.com/hubfs/Resources/services/Gold-Embrittlement-in-Lead-Free-Solder.pdf – Ariser Mar 12 '20 at 12:14

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I solved this by following @brimelrekkie's advice. I increased the heat (from 300 to 380) and changed the type of solder and it worked fast and flawlessly.

Rik Roukens
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