I was thinking of purchasing a no-clean flux pen from my supplier, but there are two options, F-SW22 and F-SW33. What do these codes mean and what types of job is each suitable for?
F-SW-22 is weakly corrosive and contains inorganic salts.
F-SW-33 is non-corrosive and is rosin free w/o halides.
You'd use F-SW-22 if there was solder-ability issues, but you must clean the board after wards.
You'd use F-SW-33 for a normal (cleaner) situation, and is advertised as no-clean . I'd recommend you clean it anyways.