cleaning the boards

[charles w. morehouse]

Steve,
The white film is left by water. Even the 99% stuff will suck up water
so never leave it open as good alcohol is hydroscopic. When that
happens, throw it out. Luck and 73.
Wayne;
W4GBW

Steve Harrison wrote:
>
> At 09:30 AM 1999-12-15 -0500, George Maier wrote:
> >Kevin:
> >A long time ago I took a NASA sponsored course in hand soldering
> techniques.  I doubt that
> >the basics have changed but you never know.  Anyway, their take (and mine
> ever since) on
> >cleaning boards and soldered connections in general has been to use 99%
> pure isopropyl
> >alcohol.  The stuff from the drug store is only 90% at best, and leaves
> some residue.
> >I've been able to find quart containers of the good stuff in electronic
> parts stores.
> >You'll need a box of Q-Tips and some alcohol brushes - you know, the ones
> with a metallic
> >grip, and fairly stiff bristles.
>
> I agree. Actually, the best at the drug store is 91%; there's also 70%,
> useless for nearly anything. I now keep a bottle of alcohol on my workbench
> in one of those little reagent plastic squirt bottles. Another bottle has
> water for the soldering iron sponge. Another is actual flux cleaner stuff,
> which works marginally better than the alcohol but definitely leaves no
> residue of its own.
>
> Unfortunately, however, even the 99%-pure stuff can leave a board looking
> really bad. I noticed some years ago that when a board was cleaned with
> something (never figured out what it was) and then cleaned again later with
> even a good flux remover spray, sometimes it would cloud up, looking
> really, really bad. The cloudy film would appear all over EVERYTHING, even
> components. Same thing sometimes happens with the alky. Nowadays, when I
> need to clean a board with unknown history, I first start with just a small
> area to see what happens. If it clouds up, I let it be. The white film
> that's left, whatever it is, can be scraped off but seems to be impervious
> to further cleaning by anything, stiff bristles or no.
>
> I wonder if the drug store can order the 99%-pure alky (maybe even
> available behind the counter)?? Should be a lot cheaper than from the
> electronics stores, which don't like to carry it anyhow since they have
> flux cleaners that are more expensive and so bring a higher profit, I
> think. The stores of the 1990's no longer stock according to what the
> CONSUMER wants to buy: they stock only what sells fast and brings the
> highest profit. Hard to blame them: it's really easy to fall behind the
> times and go bankrupt by carrying old, obsolete products whose value is
> known and appreciated to only a few old-timers and which carry no "sex"
> appeal to the youngsters. I think that's one reason the mail-order stores
> still do a land-office business these days: they have stuffs the stores
> flatly refuse to carry any longer.
>
> 73, Steve K0XP
>
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