Every now and then the issue of
solder has been discussed (in great detail) on the
Elecraft Reflector; there's also
recommendations on the Elecraft site as well. Here's where I came
out on the whole thing:
In early 2000, I started using
the Kester #24-7150-8800 '245' No-Clean 1.1% Flux (Sn62/Pb36/Ag02). The product
description states that ... "the residues from the 245 [flux] are designed
to be left on with no post-soldering cleaning." At one time early on, the
silver solder was the Elecraft choice. It can be a bit difficult if you need to
do rework, but it worked fine for me for years and made a clean finished board.
I currently use the Kester
#24-6337-8809 '245' No-Clean 1.1% Flux (Sn63/Pb37). It makes a very nice solder
connection, and it seems a little bit easier to work with. As to cleaning
boards, I've had no need, nor request for that matter, to clean any of my
boards after soldering them with this solder. I've used this solder now for
almost a year and have had no problems with it at all.