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Re: [softrock40] Here We Go - My First Newbie Question

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  • FRANCIS CARCIA
    I lay a hunk of solder next to the first joint so there is a bit of flux to make the connection. Graham Haddock wrote: Howard:
    Message 1 of 7 , Jan 1, 2007
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      I lay a hunk of solder next to the first joint so there is a bit of flux to make the connection.

      Graham Haddock <GrahamH@...> wrote:
      Howard:

      So far, I have not used or had to use an oven.

      I use a short conical point controlled temp (700 deg F)
      soldering iron, 0.015 dia Kester 44 solder, a lighted
      ring magnifying lens/lamp (for assembly), and a
      4X jewelers eye loope for inspection. For removing
      excess solder and bridges, use small size solder-wick.

      Use fine tweezers for holding and placing the chip parts.

      Anti-static mat and wrist strap for assembly of anything
      that is static sensitive.

      There are several tutorials on the web about hand assembly
      of SMT parts.

      For chip C and R, I put a small dot of solder on the board
      on one end, hold the part with tweezers while I reflow the
      solder with the soldering iron on that end. When the part
      is where I want it, go the the other end and solder it.

      For ICs, put a small solder dot on the board for one corner
      pin, hold the IC with tweezers until correct placement and
      then melt the solder at that first pin. If necessary, twist the
      IC slightly to get all pins to register, then solder one
      pin diagonally across the IC. Double check all registration.
      Adjust if necessary by melting solder at one or the other
      of the two soldered pins.
      If registration is OK, go down the row of pins on all sides
      soldering the pins. Excess solder and pin to pin bridges
      is OK at this point, most important is to solder each pin.
      Then, with solder wick, go back down each row and pick up
      the excess solder, and any bridges. You can get very a
      good looking IC installation this way.

      If you try to individually solder the pins on a fine pitch
      IC without pin to pin shorts, you will go nuts. The trick
      is to put a little extra solder on the pins, get good solder
      joints,don't care about bridges, then pick it up later with
      the solder wick

      --- Graham

      ==

      w6ids wrote:
      >
      >
      > First off, Happy New Year from our home to all of yours!
      >
      > Secondly, I have a question regarding SMT assembly as a
      > hobbiest. My experience with SMT was quite some time
      > back and involved commercial environments to include
      > SMT component placement and ovens of the commercial
      > level. Inspection used "stereo scopes" to inspect filets,
      > flow, etc.
      >
      > That said, just what are you folks doing to properly install
      > and solder the components to the board(s)? Do you bring
      > the kitchen oven or toaster oven up to around 375 Deg F
      > with a dial/digital thermometer inside or ??? Hmmm, I'm
      > wondering if I need to spend a couple of hundred dollars
      > for a suitable oven for the bench top?
      >
      > How are you applying solder paste without considerable
      > waste? Do you perform a post-solder fluxing step?
      >
      > How are the hobby assemblers inspecting their work?
      > Personally, my eyesight at 62 is just not good enough to
      > simply eyeball solder quality in SMT applications.
      >
      > What happens if there is a component shift during the
      > soldering creating misalignment or perhaps there is a
      > solder bridge or two?
      >
      > How much difficulty is experienced doing PCBs that have
      > components on both sides?
      >
      > That's it for now. Many thanks in advance for helping with
      > my learning curve.
      >
      > Regards,
      >
      > Howard W6IDS
      > Richmond, IN
      >
      > __._,_.
      >
      >


    • Bill Dumke
      Howard, Use plenty of rosin flux. You can buy it from DigiKey or Mouser in a syringe. You can also apply it with a toothpick. I put some on each pad I am going
      Message 2 of 7 , Jan 1, 2007
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        Howard,

        Use plenty of rosin flux.  You can buy it from DigiKey or Mouser in a syringe. You can also apply it with a toothpick. I put some on each pad I am going to solder.  Then after I am done soldering, I wash the flux off with CRC Brakleen, the red can version.  But do it out of doors.  You can get this at any auto parts store.  It works great on rosin flux.  The old fashioned flux cleaners such as trichlor are difficult to get these days due to health risks.  And I have found the expensive electronics supply house flux cleaners don't work any better than Brakleen, anyway.  A side benefit of washing the flux off is you can detect the solder bridges a lot easier, as well as giving more integrity to high impedance and low capacitance circuits.  You can also use a Q-tip swap to help clean up as well. 

        Bill WA9PWR

        w6ids wrote:


        First off, Happy New Year from our home to all of yours!

        Secondly, I have a question regarding SMT assembly as a
        hobbiest. My experience with SMT was quite some time
        back and involved commercial environments to include
        SMT component placement and ovens of the commercial
        level. Inspection used "stereo scopes" to inspect filets,
        flow, etc.

        That said, just what are you folks doing to properly install
        and solder the components to the board(s)? Do you bring
        the kitchen oven or toaster oven up to around 375 Deg F
        with a dial/digital thermometer inside or ??? Hmmm, I'm
        wondering if I need to spend a couple of hundred dollars
        for a suitable oven for the bench top?

        How are you applying solder paste without considerable
        waste? Do you perform a post-solder fluxing step?

        How are the hobby assemblers inspecting their work?
        Personally, my eyesight at 62 is just not good enough to
        simply eyeball solder quality in SMT applications.

        What happens if there is a component shift during the
        soldering creating misalignment or perhaps there is a
        solder bridge or two?

        How much difficulty is experienced doing PCBs that have
        components on both sides?

        That's it for now. Many thanks in advance for helping with
        my learning curve.

        Regards,

        Howard W6IDS
        Richmond, IN

      • kerrygeek1
        I used the method on Cash Olsen s web site using the hot air gun, solder paste and a coffee cup warmer. I got the heat gun locally on sale at Hobby Lobby for
        Message 3 of 7 , Jan 1, 2007
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          I used the method on Cash Olsen's web site using the hot air gun,
          solder paste and a coffee cup warmer. I got the heat gun locally on
          sale at Hobby Lobby for $12 and the cup warmer at Walgreen's for
          $3.00. I ordered the solder paste from Cash on his web site, so far
          we've used it to build 2 boards and haven't even made a dent in it.

          I'm no spring chicken either (47 next month) but a pair of cheapo
          reading glasses (also from Walgreen's) and a gooseneck light clamped
          to the edge of the desk was all I needed. I borrowed a lid of a cake
          pan to keep the parts from rolling off the desk, it's now back in the
          kitchen and my wife didn't even miss it.

          Don't worry about the smt parts, I was sweating it but it was actually
          the easiest part of the project. I was wishing more of the board was
          SMT. The other parts took much longer than the SMT parts.

          73,
          Kerry


          --- In softrock40@yahoogroups.com, "w6ids" <w6ids@...> wrote:
          >
          >
          > First off, Happy New Year from our home to all of yours!
          >
          > Secondly, I have a question regarding SMT assembly as a
          > hobbiest. My experience with SMT was quite some time
          > back and involved commercial environments to include
          > SMT component placement and ovens of the commercial
          > level. Inspection used "stereo scopes" to inspect filets,
          > flow, etc.
          >
          > That said, just what are you folks doing to properly install
          > and solder the components to the board(s)? Do you bring
          > the kitchen oven or toaster oven up to around 375 Deg F
          > with a dial/digital thermometer inside or ??? Hmmm, I'm
          > wondering if I need to spend a couple of hundred dollars
          > for a suitable oven for the bench top?
          >
          > How are you applying solder paste without considerable
          > waste? Do you perform a post-solder fluxing step?
          >
          > How are the hobby assemblers inspecting their work?
          > Personally, my eyesight at 62 is just not good enough to
          > simply eyeball solder quality in SMT applications.
          >
          > What happens if there is a component shift during the
          > soldering creating misalignment or perhaps there is a
          > solder bridge or two?
          >
          > How much difficulty is experienced doing PCBs that have
          > components on both sides?
          >
          > That's it for now. Many thanks in advance for helping with
          > my learning curve.
          >
          > Regards,
          >
          > Howard W6IDS
          > Richmond, IN
          >
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