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In article .net, wrote:
Thus spake Charlie+:

On Mon, 24 Apr 2006 09:35:30 -0700, DaveC wrote as
underneath my scribble :

Sorry nearly missed this reply as you started a new thread!
WD40 as well as being hygroscopic has corrosion inhibitors built in to
a self wetting very thin liquid - that is the whole point. Also the
Some actual experience: I did a resurrect of a Sony MZ-R30 Minidisk
Recorder/Player which had been dropped in seawater and this had stopped
working immediately! This unit had been unwashed and returned around the
world so had had about a month or more to corrode, seawater is unforgiving so

I wasnt hopeful. I removed the 1/32" FG PTH 4 layer boards completely, then

washed them in hot water, then blow dried with compressed air, you have to be

sensible with this as physical damage is possible with compressed air,
scanned them up to X10 for inspection then warmed boards (hot to touch)
then coated with WD40 for about 30 minutes, compressed air again to remove
most of the WD40 then baked in a warm oven for about 4 hours to flash off the

remaining oil, repired some obviously corroded SM joints by flux/solder and
iron reflow (under magnification!) and then reassembled. The point of the
WD40 soak was to arrest any ongoing corrosive action, it is thin enough to
wick anywhere the original liquid has gone. Worked like a champ ever since,
about 3 years now. Your board has failed under power perhaps well after the
event though and this points towards electrolytic corrosion and this may not
be recoverable whatever you do, in a multilayered board. Whatever you do I
would advise you against soaking a board in anything for a few days, imo that

would be asking for trouble! Charlie+

What do you mean by "Whatever you do I would advise you against soaking a
board in anything for a few days, imo that would be asking for trouble!"?

I'll tell you how I would call it. I have boards made, and they wash them with water for
a short period, then they blow dry them. They set out and dry. If it was soaked
in water for a few day's, I think that would spell real trouble.
These boards didn't work anyway, so they had to be baked after the short washings.
Water might very well get sucked into the layers and take a long time to
dry unless baked. Other solvents may very well start to dissolve stuff.

greg