[hpsdr] Atlas, How do I hand solder this thing?

Sun Jun 18 12:47:45 PDT 2006

Gang,

I would recommend using water soluable (organic) flux.  It is much easier to
clean, all you need is water.  With rosin core and no-clean, you need IPA or
specific flux cleaners that are smelly (technical term :-).

Lyle will tell you that as he is soldering a project, that he will wash the
PCB after each one hour time period.  Make sure you doa good job cleaning
the PCB.  Any left over flux can be activated by any mosture (such as
humidity).

Digi-Key has organic flux pens Digi-Key P/N KE1808-ND.

While you are at it, purchase organic flux solder, Digi-Key P/N KE1303-ND
(0.015").

And desolder braid Digi-Key P/N EB1173-ND (no flux, just drop some organic
flux on the area you plan to desolder)

73,

- Steve, N7HPR
 (n7hpr at tapr.org)

> -----Original Message-----
> From: hpsdr-bounces at hpsdr.org [mailto:hpsdr-bounces at hpsdr.org]On Behalf
> Of Bill Tracey
> Sent: Sunday, June 18, 2006 11:18 AM
> To: Mark Ericksen; hpsdr at hpsdr.org
> Subject: Re: [hpsdr] Atlas, How do I hand solder this thing?
>
>
> ***** High Performance Software Defined Radio Discussion List *****
>
> There are four methods I know of to do surface mount soldering at home:
>
> 1. Soldering Iron - use a conventional Iron and solder
> 2. Hot Air Gun  - use solder paste and a hot air gun
> 3. Bake - use solder paste and a toaster over
> 4. Fry  - use solder paste and a hot plate
>
> I've only personally used the soldering iron and hot air
> approaches.    For
> a small job like the Atlas I'd probably go the Soldering Iron route.
>
> Tools one will need for doing surface mount with a soldering iron:
>
> Soldering Iron  - I use 2 irons for hand surface mount soldering.
>  Most of
> the time I use a  Weller WLC100
> (http://www.action-electronics.com/wewlc100.htm) with an ST 5 tip.  For
> really small things with light traces (fine pitch (0.5 mm, 0.65
> mm) IC's) I
> use a Weller WM 120
> (http://www.testequipmentdepot.com/weller/popups/wm120.htm)  with
> an MP 131
> tip (1/64" conical) or MP 136 tip (1.8 mm screwdriver).  The WM
> 120 is only
> 12 watts so it is not good when soldering pads that have a log of thermal
> sinking such as ground pads.
>
> Thin Solder - I use .015 diameter 63/37 Rosin core solder from Kester
>
> Tweezers -- A set of tweezers with bent tips and flat grabbing
> surfaces is
> very helpful for picking up and placing parts
>
> Magnification - I use an Optivisor
> (http://www.amazon.com/gp/product/B00012C0K0/104-7091084-3502323?v
> =glance&n=3760901)
> with plate 5 - provides 2.5x magnification with an 8" focal length.  I've
> also got a 10x loupe I use for inspection purposes
>
> Toothpicks -- used to hold parts in place while soldering
>
> Solder wick -- generally don't need this for 2 terminal
> components, but for
> chips it's a must have.  I'm partial to Radio Shack # 64-2090
>
> Liquid Flux -- really only needed for fine pitch chips.  I have a Kester
> Flux Pen marked as #951 that came with a kit I find useful for fine pitch
> chips.  For resistors and capacitors I usually find solder
> provides enough
> flux
>
> Vise to hold board -- I use a Panavise or a PCB Vise (smaller boards) (
> http://www.qrpkits.com/pcbvise.html )
>
> Technique I like to use for doing resistors and caps by hand is:
>
> Approximately place a few parts using tweezers
> Cut lengths of solder  about as wide as component to be soldered, place
> solder wire on one pad next to componet
> Nudge component and solder wire to component with toothpick
> Hold down component with toothpick and hit solder wire and component with
> soldering iron until it reflows
> Once one side of component is done the other end is done by heating with
> soldering iron and applying solder.
>
> Tools for Hot air gun soldering
>
> A hot air gun  - I use a Stampabilities heat gun (
> http://cgi.ebay.com/STAMPABILITIES-HEAT-EMBOSSING-GUN-APPLIQUE-POW
DERS_W0QQitemZ8282797047QQcategoryZ16504QQcmdZViewItem
)  This gun us on special from Hobby lobby for $10 or so pretty frequently.

Solder Paste in a syringe -- one can get solder paste from Cash Olson
http://www.zianet.com/erg/ShopSolderPaste.html  (he also sells the
Stampabilities heat gun)

Basically you apply solder paste to the pads and place the components, and
then heat with the hot air gun until the solder flows.  I find this
technique quicker than hand soldering these days, but you have to have
solder paste to use it.   The other thing I like about the heat gun
approach is that it can be used to remove parts as well.

Cash Olsen's site also has a nice write up on hot air reflow:
http://www.zianet.com/erg/SMT_Soldering.html

I've not personally used  the bake or fry techniques.

Info on the Bake technique can be found @:
http://www.qrpradio.com/pub/Ham/SDR/SMT/SMT.html

Info on Frying can be found @:
http://www.sparkfun.com/commerce/present.php?p=Reflow%20Skillet

Doing surface mount work is not all that hard -- yes the parts are small
(microscopic!) but it is doable -- just take a little practice and an
attitude that it can be done.  For practice, I'd suggest the Norcal QRP
dummy load ( http://www.norcalqrp.org/ncdummyload.htm ) -- it's an
inexpensive kit with 44 SMT resistors that is probably an ideal 1st time
surface mount kit.  2nd SMT kit I'd recommend is one of Tony's (KB9YIG)
Soft Rocks ( http://groups.yahoo.com/group/softrock40/) .  3rd SMT kit I'd
recommend is the AmQRP DDS 60 (http://www.amqrp.org/kits/dds60/).    These
are all moderately priced kits with surface mount components.    Sure there
are others, these are just some ones I've done.

HTH,

Bill  (Kd5tfd)

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