[hpsdr] Atlas soldering hints

Sat Jul 15 20:50:22 PDT 2006

Sorry about that,
I must be tired. I copied and pasted his e-mail address instead of his URL.
It really is a bargain for small amounts of solder paste. All set up in 
a syringe with the correct size applicator
Here is is his website:
http://www.zianet.com/erg

Bob   K6GGO

Bob Fish K6GGO wrote:

>***** High Performance Software Defined Radio Discussion List *****
>
>Hi All.
>You may want to pay a visit to this guy's website. I am in the process 
>of building the Spectrum Analyzer kit that he sells. He has a tutorial 
>there for a SMT soldering technique using a hot air gun and hot plate 
>that works very well indeed. He will sell you a syringe full of solder 
>paste for 5 dollars. Solder paste is (IMHO) the secret to the whole 
>thing. No tinning required, just put a small amount of paste on each 
>pad, squish the components down into the paste and heat with hot air 
>until the solder reflows. The component even centers itself on the pads 
>due to the surface tension of the solder. Best technique I have seen 
>that didn't involve buying a 2500 dollar reflow oven  Nice guy too, very 
>helpfull. The spectrum analyzer is pretty cool also, but we aren't going 
>to be needing one of those are we?
>
>Here is his website,
>KD5SSJ at zianet.com
>
>Bob   K6GGO
>
>Mike Naruta wrote:
>
>  
>
>>***** High Performance Software Defined Radio Discussion List *****
>>
>>Thanks to the SDR group, I have done my first
>>foray into surface-mount soldering.  Here's
>>some hints that worked for me.
>>
>>
>>I use a lighted magnifying device like the
>>GC Electronics 22-423.  I can get up close,
>>there's lots of light, I can take my glasses
>>off to take advantage of my nearsightedness
>>without worrying about solder or flux
>>splashing into my eye, and it directs the
>>flux smoke away from my face.
>>
>>I use a temperature-controlled soldering iron.
>>This is terrific.  My old irons were always too
>>hot.  And different heats are useful for the
>>different components.  The by-pass capacitors,
>>for example, work best for me at 325 C (620 F).
>>The DIN connector pins at 350 C (660 F).  The
>>LEDs below 315 C (600 F).  (Lead-Tin solder)
>>
>>Thanks, guys, for the intro to the water-soluble
>>flux.  This made cleanup a dream.  I just held
>>the board under the faucet and scrubbed with a
>>toothbrush.  All the flux came off and it looks
>>professional.  The Kester solder I'm using is
>>24-6337-6422.  (63/37, 0.015, water-soluble).
>>
>>I also hit the board and connector pins with a
>>felt-tip flux pen (Kester 2331-ZX).  Watch out
>>for the manufacture date on the flux pens; I got
>>a batch with about 2/3 of their shelf life gone.
>>
>>Note:  This flux is flammable.  I excitedly
>>discovered the flame going up a piece of wire
>>that I was tinning.
>>
>>Put a large sheet of blank paper under your work
>>area.  This helps when you drop a part.  You will
>>drop a part.  Oh, also clean the floor before you
>>start.  I gave up on a capacitor I dropped on the
>>floor.  Sure glad that I ordered extra parts for
>>my Atlas.  I lost two capacitors; one that hit the
>>floor and one that arced off towards the scopes.
>>
>>For holding down the SMDs, I use an old push-pin.
>>I use tweezers to position the SMD, center the
>>point of the pin on the SMD and apply moderate
>>pressure to hold it while soldering.
>>
>>Tweezers with a bent end are more comfortable.
>>
>>A way to hold the circuit board stationary is a must.
>>
>>I tried tinning the pad with a blob of solder first,
>>but that gave an uneven surface.  This caused more
>>of a Tiddlywinks effect on the SMD.  I tried my
>>dual-iron tweezer, but I had trouble getting a good
>>position on the SMD and looked like the SMD got
>>very hot.  The tweezer irons are great for removing
>>soldered SMDs.
>>
>>I tried laying a small, cut piece of solder next to
>>the SMD while heating it, but spent a lot of time
>>fussing with the solder and SMD to get them lined-up
>>first.  I don't have access to soldering paste.
>>
>>The technique I settled into is to use the residual
>>solder on the SMD to tack one end into place by
>>putting the iron against the pad and SMD.  Then,
>>after a cooling period, apply solder to the other
>>end of the SMD.
>>
>>Note:  Too much heat and the other end de-solders
>>the tacked side and you have an SMD on the loose.
>>
>>Note:  It takes LESS solder than you expect.
>>
>>Note:  The LEDs just have Gold plating, no solder,
>>so you need to add some solder to the pad first.
>>
>>After the soldered side cools, you can go back to
>>the original side and solder it.
>>
>>Do not dwell on the connection with your iron.
>>It is tiny and you're putting a lot of heat on it.
>>That's why you turn down the temperature.  I saw no
>>signs of pads lifting.  For the DIN connector pins,
>>if you have the iron on the connection for more
>>than two seconds, you need to change something.
>>
>>For the DIN connectors, I used a screw, lock washer,
>>and nut to attach them to the board first.  The plastic
>>of the DIN connector probably has enough yield to hold
>>the nut on, but why take chances.
>>
>>I started on the center row of pins, soldering every
>>other pin, then came back and soldered the skipped pins.
>>This helped spread the heating effect, but probably
>>wasn't necessary.  Then I when down one side and
>>alternated pins again.  By having the alternating
>>pattern, it helped distract me from the tedious task.
>>
>>Do not be in a hurry to solder the pins.  Take your
>>time with each one.  As I learned from manufacturing,
>>inspection is only about 50% effective.  It will be
>>much harder to diagnose an locate a faulty connection,
>>than to focus on each one the first time.  Give
>>yourself breaks.  This is supposed to be fun.
>>
>>Thanks SO much to the great folks in the group who
>>developed this and encourage us to do it ourselves.
>>What an exciting time in amateur radio!
>>
>>
>>Check out photos of my soldering stuff at HamSDR.com
>>< http://www.hamsdr.com/profile.aspx?id=76 >
>>
>>Mike - AA8K
>>_______________________________________________
>>HPSDR Discussion List
>>To post msg: hpsdr at hpsdr.org
>>Subscription help: http://lists.hpsdr.org/listinfo.cgi/hpsdr-hpsdr.org
>>HPSDR web page: http://hpsdr.org
>>Archives: http://lists.hpsdr.org/pipermail/hpsdr-hpsdr.org/
>>
>> 
>>
>>    
>>
>_______________________________________________
>HPSDR Discussion List
>To post msg: hpsdr at hpsdr.org
>Subscription help: http://lists.hpsdr.org/listinfo.cgi/hpsdr-hpsdr.org
>HPSDR web page: http://hpsdr.org
>Archives: http://lists.hpsdr.org/pipermail/hpsdr-hpsdr.org/
>
>  
>

 1153021822.0