[UK-CONTEST] Cleaning flux off PCBs

[Ian White G/GM3SEK]

G3SJJ wrote:
>Hi all, I am just in the process of changing the Source Driver chip in my
>Topten Band Decoder. I've got the old 18 pin chip out and about to install a
>I.C. carrier so I can try various chips. There is a fair bit of flux around.
>What is the best cleaner to use?

Do you mean "What is the best I can buy?" or "What is the best thing I'm 
likely to have in the house on a Sunday evening?"

For the former, I like Electrolube 'Ultrasolve'. You can get it from 
most of the big suppliers (see my 'In Practice' web page for contact 
details). I particularly like the aerosol can which dispenses the 
solvent through a stiff brush head (go to http://uk.farnell.com and 
search for product code 725651) though you can obviously use an old 
toothbrush instead.

Cue Dave YMC, who will no doubt have his own favourite to recommend.

It always helps to chip off as much flux as you can, so the solvent has 
less to do. The big mistake is using too little, which only spreads the 
flux around, and then evaporates leaving the whole board sticky. If you 
have only been working on one small area, tilt the board so the 
dissolved flux takes the best possible path off the edge. The best path 
is usually the shortest, but not always.

If the question was "What's in the bathroom cabinet or under the kitchen 
sink?" try isopropyl alcohol, rubbing alcohol or meths. All of these 
household solvents may contain water, and may leave residues on the 
board, so go over the board again later with a proper solvent.



-- 
73 from Ian GM3SEK         'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek