Solder question

[Jim Patchell]

    Technically you should clean rosin flux off the PCB.  At the very least
it makes the board look nicer, at the most, it will prevent leakage current
to critical parts of your circuit.

    The silver bearing solder has the silver in it to prevent silver from
dissolving in the solder.  Silver (and copper as well) are soluable in
solder.  The 2% silver saturates the solder preventing any more silver from
disovling.  This can be critical when soldering SMT's, as the pads on some
smt's are made from silver.

    As far as flux cores, my preference is solder with an organic flux for
soldering printed circuit boards.  This allows you to clean the boards with
regular soap and water.  I use Kester 331 myself.  But you have to be very
careful with this stuff.  If you accidently use it with rosin flux, you get
a real big mess that just won't clean up no matter what you use.  Been
there, done that.  Also, I do not use Kester 331 for making cables, doing
wiring of any sort, or building bread boards.  Not using it wire is a good
idea because the flux does wick up under the insulation where it cannot be
cleaned and it is corrosive.

    Just my opinions.

    -Jim

--M wrote:

>     I have a question about solder and cleaning rosin. I have been
> soldering with .022 "Silver Bearing Solder" 62% tin 36% lead and 2%
> silver. I like this solder it's very fine and solders nicely very clean
> to work with. Everything I have done with this seems to work just fine.
> Everybody seems to recomend rosin core solder. I got some of this and it
> seems to work just as well but leaves rosin on the PCB when I am done. I
> have never bothered to clean this off is there a potential problem here?
> How would I go about cleaning this off, does it matter?
>
> Thanks
>
> --M