Connect with us

SMD Soldering

Discussion in 'General Electronics Discussion' started by screwball, Jan 2, 2013.

  1. screwball

    screwball

    89
    1
    Jan 9, 2012
    Okay, so I put a post up the other day in regards to soldering SOT 23 component and my mind was put at ease,

    Today i received them and theyre much more smaller than intended,
    I want to atleast try with them though, SMD allows me to throw alot more in a smaller space.
    Also, i ordered 500 x 1206 resistors so they won't be going to waste i guess.

    Anyway, to get to the point, im just after some SMD hand soldering tips if anyone could help me out? My irons not great, definitely going to invest in one some time soon :)
     
  2. BobK

    BobK

    7,592
    1,636
    Jan 5, 2010
    Get a small conical tip.

    Use a magnifier, I use one on a headband that you can flip in and out.

    Use a solder paste syringe. Squirt a bit of solder on each of the pads. Use tweezers to place the part (not the kind from your medicine cabinet, really sharp pointed ones designed for this purpose.) The solder paste will hold it in place. Just barely touch the tip of the iron to each pad.

    Practice makes perfect (I am not there yet though)


    Bob
     
  3. screwball

    screwball

    89
    1
    Jan 9, 2012
    Thanks, sounds good advice ;)
     
  4. vitroblue

    vitroblue

    4
    0
    Jan 2, 2013
    if you use a water soluble flux pen and really pointy tweezers you might not need a small conical tip for the hand soldering iron; as long as it is in good condition it'll work. maybe you wouldn't even need the syringe nor the solder paste

    1) put some flux on the pads,
    2) put a little bit of solder on the pad, as little as possible, dont let it form a bump, but cover all of the pad
    3) place the part and hold it with the tweezers
    4) put some more flux again if you like, normally there's no need
    5) gently touch the part pin and the pad to solder them together, just a quick peck

    if your solder points look like tootsie pops, you used too much solder. remove the excess with a cooper mesh (fluxed copper mesh gets better results).
    don't let the iron get dirty, clean it every time using a wet sponge
    you'd might like to clean the board after finishing using alcohol on a small brush
    also use the magnifier and a box cutter to check if every pin is soldered (try to lift the pins with the blade) and to find solder shortcircuits.
    if you got a solder shorcitcuit, use the flux pen and then the (fluxed) copper mesh to remove it

    this way i've soldered 0603 (1608 metric), 100 lqfp .4 and tssop packages with perfect results despite the size of the tip
     
  5. vitroblue

    vitroblue

    4
    0
    Jan 2, 2013
    ... of course lets not exaggerate that size of the tip. it is recommended to use a tip the size of the smallest pin you want to solder, but if you do that the biggest pads are gonna give you headaches coz they take too long to heat up and switching tips is s greater waste of time. so the biggest tip i've used soldered 3 or 4100 lqfp .5 pins at once but it was flat like a screwdriver. such tip lemme work on the tru-holes just as easy as the smd

    another tip, if you are drawing your own footprints, its way easier to solder smd yourself if you make the pads longer than the specs recommend. for example, a 0603 having two 60x35 mil pads at 30 mils from each other should be easier to solder than the regular 30x35 mil pads. of course this will take away your space, but is an easier start. once you get better at this, you can shrink those pads
     
  6. screwball

    screwball

    89
    1
    Jan 9, 2012
    @vitroblue thanks, its much appreciated your advice,

    I will try all said, hopefully with good results, if i suck then im sure i will be posting again :p

    Cheers
     
  7. BobK

    BobK

    7,592
    1,636
    Jan 5, 2010
    vitroblue,

    I used your method until I found paste solder. Paste solder is much easier, for me anyway.

    Bob
     
  8. KJ6EAD

    KJ6EAD

    1,114
    157
    Aug 13, 2011
    Surface mount soldering 101:



    SOT23 installation (with bad audio):



    1206 installation:



    Professional techniques:

     
    Last edited: Jan 4, 2013
  9. screwball

    screwball

    89
    1
    Jan 9, 2012
    Thanks everyone, Soldered a few transistors and quite a few 1206s yesterday evening with moderate ease,

    One problem I did have though, I was soldering a wire also and it would not allow to be soldered easily, it was asif the solder would not stick to the wire, is this because of grease on it or something? Would brushing alcohol on something like this help to solder easier?
     
  10. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,171
    2,687
    Jan 21, 2010
    Flux is the thing you need. If it's a solid wire, beware enamel insulation or heavy oxidisation. Both of these can be removed with some fine emery paper, drawing the wire through a folded piece a few times.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-