[sdiy] solder questions

[mirwin at qouest.net]

I prefer to use Kester "44" for prototype work - and  for circuits that 
demand low board leakage I clean off the flux with either acetone 
(widely available) or commercially-made flux remover (ethanol, 
isopropanol and ethyl acetate is a typical formulation). A final rinse 
with distilled water followed by thorough drying and spraying with 
silicone conformal coat to protect the board against contamination. As 
other posters have mentioned, air-wiring also works fine for low-leakage 
stuff, just make sure the components are clean.

I have had problems with boards that were soldered with water-soluble 
flux. That stuff needs to very very thoroughly washed off, again with a 
final rinse of distilled or deionized water, or there will most 
definitely be leakage problems that are enough to disrupt sensitive 
circuits such as sample-holds or wide-range oscillators. 
Regards, Mike