You too can solder SMD components

Discussion in 'General Electronics Chat' started by wannaBinventor, Sep 18, 2010.

  1. wannaBinventor

    Thread Starter Member

    Apr 8, 2010
    I've managed to progress into areas where I found myself needing components only available in SMT packages. I thought it was going to be a really big, difficult ordeal and that I would require some ridiculously tiny tip on my iron. I posted a video a while back with some guy soldering a TQFP package by just dragging his iron across the leads. He described it as an "advanced technique." This isn't the case.

    All it takes is:

    Solder Paste
    Desoldering Braid
    Magnifying glass.

    I was able to just dab a little solder paste on the board, hold the TSSOP in place with tweasers, and then lightly drag the iron across the leads. Soldered right up. I was also able to do the same with some 0402 inductors and capacitors.

    Long story short:

    A lot of people (myself included) seem to get hung up with the idea that soldering SMT components is too hard and should be avoided, but it really isn't that bad.
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010

    Chips like the one pictured are EASY to solder, especially when you use liquid soldering rosin for a clean up pass. No matter how the soldering looks when you are done(even with minor shorts between leads) they can be easily tidyed up by putting excess liquid rosin on them and reapplying the iron at the end of the leads.

    The rosin causes the solder to bead up and flow much more freely, allowing the coarse soldering job to become finely filleted and shiny. It also causes the solder to remove itself from between the leads of the device.

    I have used this technique to repair freshly manufactured boards that suffered poor soldering on the memory or CPU chips at work. The pitch of the leads was much finer than those pictured above. The memory chip had 50 leads in an approx 1 inch row on each end. Much to small to solder individually, but still 'fixable' using the excess rosin technique.

    It requires lots of cleaning with anhydrous alcohol afterwards, but I've fixed enough boards this way to be sure it is a good method to recommend. Of course if there is a LARGE solder short, it should be removed with a suction device or with solder braid before using the excess rosin method.

    The board above could use a little cleaning up of its soldering job with this technique. It would leave a professional looking solder job anyone would be proud to show off.

    Last edited: Sep 19, 2010