Soldering SMD components

Discussion in 'Homebrew and Kit Projects' started by W5OXL, Jun 8, 2021.

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  1. G8FXC

    G8FXC XML Subscriber QRZ Page

    The order really doesn't make a lot of difference if you are going to have solder the SMDs. The issue that might hit you is the fact that SMDs are generally low to the board compared with through holes - make sure that you fit the smaller devices first so that you have easy access - don't end up trying to solder a tiny SMD resistor surrounded by large through hole devices!

    Martin
     
  2. W5OXL

    W5OXL Ham Member QRZ Page

    When you say high wattage iron, how much are you inferring? I have 25 and 40 watt irons for component soldering in addition to a 15 watt iron I got for small components.
     
  3. AD5GH

    AD5GH XML Subscriber QRZ Page

    Hi Bill,

    I solder SMD parts first, followed by through hole. Provides better access to the SMD parts and allows the board to lie flat for SMD parts.

    I use a Hakko FX-888D soldering iron set at 650 - 750 deg depending on component and ground connections, 0.020" solder (Sparkfun TOL-10242), tweezers, 45-degree angle nose pliers, and a lighted magnifying glass. I use the tweezers to place and hold component on the board while I rest one arm of the pliers on the component. I then solder one connection, remove the pliers, and solder remaining connections.

    All of the boards here were assembled with this technique.

    Regards,
    Rod AD5GH
     
  4. VK2TIL

    VK2TIL Ham Member QRZ Page

    I like my Lindstrom TL SM103-SA tweezers, designed for SMD with little "grabber" tips;

    https://www.newark.com/lindstrom/tl-sm103-sa/tweezers-postioning/dp/53R2115

    Another useful (and cheaper) tool is a bamboo skewer with the tip cut-off at about 45 degrees;


    Skewer 2.jpg


    This makes a little flat "foot" that holds an SM part down; it is not smooth like tweezers or metal tools and doesn't slip.
     
    KA0HCP likes this.
  5. W5OXL

    W5OXL Ham Member QRZ Page

    I would love to have a Hakko soldering station. But I was looking for a rework station with the hot air part. Have a friend who worked in down-hole oil/gas instrumentation for a major oilfield company. He recommended the hot air soldering equipment a decade ago. He even demonstrated its use at a club meeting. I have looked on line and I find that there is a Chinese brand , Yihua, that is advertised multiple places. Does anyone have experience with this brand?
     
  6. N5HXR

    N5HXR Ham Member QRZ Page

    I have one of those (I think it's a family of clones, and I have this one). It definitely works -- I've used it a few times. I am confident that there are many reasons to buy a more expensive one, though :). I do most of my SMD assembly with an iron, and only use the hot air for (A) desoldering multi-pin things and (B) soldering things that take too much thermal energy (e.g., this transistor with all the thermal vias).

    I can't speak to the long-term survivability of this thing with constant use, but it gets hot, blows air, and generally melts solder quite well for me.
     
  7. W5OXL

    W5OXL Ham Member QRZ Page

    They have some combo stations with both the hot air and soldering iron. Yes, I figured it was a clone of something better. The Hakko soldering iron alone is over $100 but is probably worth it. It is convincing the XYL to let me spend the money. The few hundred dollars for a low end Hakko rework stations is out of the question.

    I will start with my fixed iron and see what results I get.
     
  8. N5HXR

    N5HXR Ham Member QRZ Page

    If you're low on funds, I highly recommend the Xytronic LF-389D. I used it for about 8 years before moving to a Hakko FX951, and I never really had any problems with it. It's temperature controlled, there are lots of tip options, and it's probably $60-70. I did plenty of SMD stuff on it.
     
  9. KF5FEI

    KF5FEI Ham Member QRZ Page

    Surface mount first -- study parts placement so you don't paint yourself in a corner by installing one that blocks another. Typically smallest to largest parts - sizewise.
     
  10. GNUUSER

    GNUUSER QRZ Member

    lightly tinning the pads and a little flux on the smd leads helps a lot.
    position smd and hold down firmly until solder solidifies.
     

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