I worked around a small industrial assembly line. We had a vapour
degreaser. It was a special vat that contained a mist of a powerful
solvent and "lid" that was created by a special airflow, like the
laminar flow "doors" on some shopping malls that keep the cool air
conditioning in without a physical door. The boards were lowered
into the fog with large forceps. If you put your hand in there it
came back white! completely stripped of all oils. This thing was
a miracle machine. The board went in dry, came out dry, but was
visibly wet below the fog line. The solder flux would completely
disappear as if by magic. Spoiled us all rotten. We would fix
a PC board, run in and dunk it into the degreaser, and there was
no evidence at all that a repair had been made.
Now I am back to isopropyl alcohol. Rubbing alcohol from a drug
store is OK, but the isopropyl alcohol "for injection" is better.
It is 95% or 99% instead of the 70% that rubbing alcohol tends to
be. Methanol, wood alcohol, is a bit more likely to attack plastics
and parts and more poisonous. Acetone and relatives like nail polish
remover, will instantly deface many plastics. For our cleanup, we
use pure isopropyl alcohol routinely, with a bit of scrubbing from
a Q-tip swab. This assumes classic rosin core solder, not some
nightmare new hygroscopic fancy stuff. Carbon TetraChloride is a
BAD ACTOR and should not be messed with. I know, in the old days
we used to bathe in the stuff, but we know better now. Benzene is
another chemical that should be avoided. Methyl Ethyl Ketone is a
relative of acetone that is a bit less likely to attack plastics and
common in many "dry cleaning" type solvents. DiChloroMethane has
replaced Chloroform and Carbon Tet as a slighly more health friendly
solvent, but it is quite strong and will attack a number of things you
do not want dissolved. In the organic liquid category, Isopropyl
alcohol is the winner for effectiveness, safety to self and safety
to parts.
PC boards can be rather rugged. When doing research with old
datalogging recorders on the beach in the salt spray with salt
physically encrusting some of the PC boards, I would pull all the
boards out, throw them in the sink, scrub them up like dirty dishes,
rinse them off with isopropyl alcohol, hang them on an improvised
"clothes line" to dry, all with only beneficial results.
A few people were surprised to see me working up a good lather with
a soft brush on a sink full of PC boards, but it kept those poor old
dataloggers online for months. Of course you have to be careful around
parts that are not sealed like some relays and switches, but I have
recovered electronics that have been hideously abused when it was
essential to try to save them.
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