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

[Bill Tracey]

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-POWDERS_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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