On Tue, 2 May 2017 08:45:41 +0100, Ian Jackson
wrote:

In message , rickman
writes
On 5/1/2017 12:39 PM, Sjouke Burry wrote:
On 01.05.17 18:07, Micky wrote:

WD-40 to clean electric contacts?

I'm on vacation and renting a room, and my landlady has a combination
CD/Radio/Cassette?, very compact, portable, works well except fo the
little on/off/CD slide switch.

The switch doesn't easily make contact, even when pushed to and past
the On position. So it's hard to get the radio on, and it turns off
by itself in about 30 minutes. Moving the switch back and forth 10
times to clean it hasn't worked yet.

Normally what I would do is spray contact cleaner or tuner cleaner in
the switch from above, where the plastic slider that goes over the
switch is, And normally that doesn't accomplish much.

Even taking such things apart and spraying the switch from underneath
has taken longer to work than for rheostats, for example, and here I
don't want to take it apart. She's only my landlady.

I don't know where in this non-English-speaking country to buy
contact cleaner and she might balk at the extra money, but she does
have something in an aerosol can that looks mighty like WD-40.

I have this vague recollection that WD-40 is good to clean electric
contacts?? Either that or it's bad for them. Should I try it.

BTW, I want to use the radio, so that's one big reason I want it
fixed. When it stopped playing while she was there, she said, "Oh,
yeah, maybe that's why I bought another one" (She speaks English.)

Trying it, will certainly not make things worse.
And cleaning/flooding the switch a day or two later with
something volatile,(alcohol,turpentine or such) will take
care of the wd40 residue(maybe).
I don't think it will make things worse.

Very bad idea. Contact cleaner is specifically formulated for the job
and won't cause any harm to electronics. A friend used WD40 on some
very expensive chemical instrumentation as "preventive maintenance" and
the volatile solvents in it melted the shafts to the collars on the
pots freezing them. So he had a service call the next day where he had
to replace the pots he sprayed.

While I'm sure that there have been occasions when a squirt of WD40 has
dissolved everything in sight, I've been using it for decades, and I've
never found it has ever caused any such damage.
I can tell you one thing it is DEFINITELY no good for.
I have EuroVynyl brand tilt turn side dlider windiws - made with Rehau
vinyl extrusions. When cleaning the windows my wife drcided to
lubricate the pivot blocks with WD-40.She then could not get the
blocks to slide in the track. I ended up moving the top block far
enough to pop the window sash out of the sliders, drive the block to
the end, cut the top of the track and pry out the block. Luckily I had
purchased a few sets of the lovot blocks and other parts fron the
manufacturer when I bought the windowsn(I worked for the dealer) so I
was able to replace the swollen blocks. No amount of soaking in
alcohol or any othe substance was effective in returning the block to
the proper size. No idea what kind of plastic it was- but it sure
didn't like WD-40.

If using wd-40 to disolve hardened grease in a slide switch, ALWAYS
finish the job with a contact cleaner to flush out the remains.

In automotive switches, like power window, door lock, headlight, etc,
when I've had to dissassemble them and clean/polish contacts etc I
re-assemble using a synthetic silicone based grease which won't
harden.WD 40 can be an effective solvent for softeninf and removing
the old "boogers" - . It can also be acceptable for "burnishing"
plug-in connectors and keeping them from corroding - things like
wiring harnes plugs - but the old TV Tuner dope works a lot better if
you can still find it.