DPRG mailing list archives: [DPRG] SMT Soldering

Fri Jun 6 12:56:29 CDT 2008

DIP is through hole. Very easy.

TQFP a little tricky but use a little too much flux and not too much
solder, and the solder just wicks up the leads.

MLF has the pads under the part. Doable, but I would not recommend it
for the beginner. The layout is a little tricky. They also often have a
ground/heat pad in the middle that you can not hand solder.

For a beginner I would recommend 1206 package for resistors and
capacitors.

0805 is not bad, and with practice 0603 is not too hard either. 

0402 is very easy to lose and harder to solder. 
0201 do not even think of it or the smaller 01005, I can't even see. 

The most important thing is flux. I recommend water soluble flux, and
when you are done wash the board with hot water and a toothbrush. (Do
not use on wires.)

No clean is another option, but it does not solder as easy (but is
acceptable) but leaves the board looking dirty. If you clean you need
alcohol.

The rosin flux -- stay away. It leaves sticky residue and can only be
washed with alcohol and toothbrush. Water does not touch it.
Unfortunately this is the easiest to get.

Acid core solder and flux are for copper pipes and should never be used
for electronics.

You should have a bright light over your work area. Some tweezers, or a
couple of tooth picks (to hold it in place while you solder.) and a
soldering iron with a temperature readout. 630 F is what you want to
solder lead at.

I like a soldering iron with a flat tip like a screwdriver and usually
use one about .06" give or take. I do not like the pointed pencil type.

Kip

On Fri, 2008-06-06 at 12:21 -0500, Eric Sumner wrote:
> I am working on laying out one of the boards for my thesis, and I have
> no experience with surface-mount soldering.  The processor that I am
> using is available in DIP, TQFP, or MLF; how hard will it be to
> hand-solder either the TQFP or MLF package?  Also, which size of
> resistors and such would you recommend?
> 
>   -- Eric
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-- 
Kipton Moravec KE5NGX
"Always do right; this will gratify some people and astonish the rest."
--Mark Twain