On Friday 02 September 2005 03:30 am, Mike Harrison scribbled:
> For stuff like SOT23s, put a bump of solder on one pad, place the part over
> the footprint with tweezers,  and flow the solder while seating it downt.
> Same method for tacking the initial corner of ICs.

Maybe it's my tweezers, but I had tried those and could not hold the part 
properly.  I'm also guessing it had a lot to do with my blood-caffeine level.
IC's are not a problem -- I can slide them in place and press on it with a 
finger while I tack down a corner.  If I try to hold down an SOT-23 device 
with my finger, it usually tilts the opposite side up and flips it over and 
ends up elsewhere on the board.


> For 2-sided ICs, putting flux on the bottom of the pins as well as the PCB
> helps a lot. If you have a wide enough bit, one method is to put solder on
> all the pads, put flux on the pins, hold the part in place and reflow the
> whole row down onto the solder.

What are you calling a "2-sided IC"?  Are you refereing to IC's with pins 
under them, such as PLCC's?


> For braiding off excess solder, one method to minimise heat is to hold a
> loop of  braid over the iron bit and then touch the braid/iron combination
> onto the pad.

That sounds awesome -- I must try that.  So far I've been laying the braid on 
the pins and pulling/sliding it across all the pins while I simultaneously 
hold the iron on the braid and slide it together with the braid.


> "Soder-Wick" brand is the only braid worth using. There is s HUGE
> difference between good and bad solder braid.

Will look for it.  So far I've been using Techspray .055" braid.


> If reworking, ALWAYS clean off old flux and put fresh on. You can never
> have too much flux, as long as it is fresh.

Actually, I always clean off flux after soldering.


> I like the chemtronics circuit works flux pens (cw8200) - the spray stuff
> is messy and too sticky.

Yes, the pen is awesome -- I use the CW9200.


> A screwdriver with a blob of blu-tak on the end makes a good substitute for
> a vacuum pick-up tool.

Blu-tak?  Will look for it.

Thanks,
-Neil.





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