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

[Hughes3hns at aol.com]

It usually takes about a week of classroom time to learn all of the 
proper ways to solder any component so you have been getting quite a bit 
of info in the condensed version...

When I solder a SMT whether a single component or an IC, I tin one pad 
first and then place the part down on that pad , holding it with the 
bent tweezers, then reheat that pad until the solder flows around the 
lead. Then I will lay the solder in the opposite joint and heat it until 
it flows. Unless it is a ground pin you should only need to stay about 4 
seconds. And unless you have a Metcal Talon or are extremely coordinated 
trying to use two soldering irons to hold an 0805 component will just 
result in a nervous breakdown.

  If you are soldering an IC then try not to go from one pin to the 
next, jump a pin or two or you could heat the part beyond it's spec.

What temperature you use will also be determined by the wattage of your 
iron...A 150 watt gun at 700F will fry all of the pads but if you have a 
25 watt iron at 700F with a very small tip then you might not be able to 
transfer enough heat to the joint to make the solder flow properly..
If you can then start at a lower temperature and work your way up to a 
comfortable temperature. You may not damage the component but you can 
quickly delaminate the board (say "LIFT A PAD" ) with too much heat.

You should always use the smallest possible solder, too much solder is 
just as bad as too little. With too much you may just be dumping solder 
onto a cold solder joint. If you have a good enough magnifier then you 
should be able to see the solder "FLOW" on the pad and around the pin.
(If the pad and component are clean ( well fluxed) and you have heated 
the joint long enough to raise both the component and the pad up to the 
melting point of the solder)
If you practice on the outside pins of the DIN connectors then you 
should be good enough to do the SMT. The inner row of pins is connected 
to Ground but there is a thermal pad so it is not quite as bad as it 
could have been.

Add this to everything else and you should be in fine shape.
And if not .....Well you can always opt for the Assembled board.......

I truly about had a coronary when I heard about the practice of putting 
solder everywhere and then wicking off the excess....

Peter Hughes
N7BMG
TOO Many times certified Mil Spec 2000 , IPC-A- 610  :-)

Ahti Aintila wrote on 6/18/06, 4:57 PM:

 > ***** High Performance Software Defined Radio Discussion List *****
 >
 > On 18/06/06, Steven Bible <n7hpr at tapr.org> wrote:
 > > ***** High Performance Software Defined Radio Discussion List *****
 > >
 > > Mike,
 > >
 > > I set my irons for 700-750 degrees for regular leaded 63/37 solder.
 > For
 > > no-lead solders, you'll have to experiment (and read the data
 > sheets) but
 > > I've seen 800-850 degrees.
 > >
 > > Don't worry too much about cooking SMT parts.  They can handle the
 > temps.
 > > Just do it quickly, and don't linger too long.  So far I have not
 > damaged a
 > > SMT part while hand soldering for the past 6 years.
 > >
 > > 73,
 > >
 > > - Steve, N7HPR
 > >  (n7hpr at tapr.org)
 >
 > Steve,
 > You gave excellent soldering instructions, thanks! Those temperatures
 > work for me, too. Actually, I seldom need to go above my usual setting
 > 400°C (752°F) for Sn-3Ag-0.5Cu. Please notice that the temperatures
 > given are much above what they specify for the components and FR-4.
 > This is the temperature of the tool tip for quick (few seconds) and
 > effective transfer of heat to the solder point. Long time heating of
 > the solder point to that temperature certainly will damage the PCB and
 > components.
 >
 > Here are some conversions  from F to C for the rest of the world:
 > 700°F  371°C
 > 750°F  399°C
 > 800°F  427°C
 > 850°F  454°C
 >
 > 73, Ahti OH2RZ
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