Greasing up switches and connectors?

[DaveC]

Cleaning up an old rotary mode switch used for 5v logic levels. It has some
kind of grease in it.


…which has always confused me: grease is an insulator (well, the grease in
this switch is—just tested and it’s infinite ohms).

I read that dielectric grease is good to keep contacts sealed against the
elements that have high physical pressure (which overcomes any separation
provided by the grease) but that signal and other low voltages grease is
contra-indicated.

What say y’all?

Thanks.

[dca...@krl.org]

On Saturday, March 5, 2016 at 12:14:19 PM UTC-5, DaveC wrote:

> I read that dielectric grease is good to keep contacts sealed against the
> elements that have high physical pressure (which overcomes any separation
> provided by the grease) but that signal and other low voltages grease is
> contra-indicated.
>
> What say y'all?
>
> Thanks.

http://www.te.com/documentation/whitepapers/pdf/p154-74.pdf

More important to use an low voltage and signals.

Dan

[N_Cook]

Over the years all those problematic radio multiway wavechange and tape
recorder play/record slide switches. I never saw grease inside them and
the failure was due to black corrossion product copper suplphide? which
is an insulator that a phosphor bronze contact could not wipe/break
through to make contact. The worst black was at the more open ends to
the air, rather than the core of the switch body.

[Ian Field]

"DaveC" <n...@home.cow> wrote in message
news:0001HW.1C8B4B670...@news.eternal-september.org...

> Cleaning up an old rotary mode switch used for 5v logic levels. It has
> some
> kind of grease in it.
>
>
> …which has always confused me: grease is an insulator (well, the grease in
> this switch is—just tested and it’s infinite ohms).

When I worked for a calibration firm, they had special contacts grease for
the old decade boxes. AFAICR: it was called Elvolube - but I haven't been
able to find it online.

Often I use GT85 - its like WD40 but PTFE enhanced, it doesn't interfere
with contacts but the solvent destroys any ABS plastics in anything you
spray it on.

[N_Cook]

On 05/03/2016 17:14, DaveC wrote:

Can we summarise this thread by saying -
Any grease is better than no grease, in low voltage, wiped contact
situations, as long as the grease doesn't go hard with age or otherwise
degrade or corrode the contacts itself

[Ian Field]

"N_Cook" <div...@tcp.co.uk> wrote in message
news:nbjbp3$uo0$1...@dont-email.me...

> On 05/03/2016 17:14, DaveC wrote:
>> Cleaning up an old rotary mode switch used for 5v logic levels. It has
>> some
>> kind of grease in it.
>>
>>
>> …which has always confused me: grease is an insulator (well, the grease
>> in
>> this switch is—just tested and it’s infinite ohms).
>>
>> I read that dielectric grease is good to keep contacts sealed against the
>> elements that have high physical pressure (which overcomes any separation
>> provided by the grease) but that signal and other low voltages grease is
>> contra-indicated.
>>
>> What say y’all?
>>
>> Thanks.
>>
>
> Can we summarise this thread by saying -
> Any grease is better than no grease,

Some mechanical engineering greases contain a significant proportion of
water.

Not certain - but that may open the possibility of corrosive decomposition
products.

Many greases are lithium based, its probably bound up in stable compounds,
but very reactive if it gets loose.

Molybdenum grease is probably OK except in high voltage or high impedance
work - graphite grease is probably not OK for anything electrical. Graphite
is the lubricant of choice for brass, such as locks etc.

PTFE penetrating oil works well on contacts, as for grease the one I know of
is Finish-line PTFE fortified bicycle grease. It works OK on heavy contacts,
but may isolate the wiper on light duty switchgear.

Silicone grease is exactly opposite to hygroscopic - it repels water.

[tabb...@gmail.com]

On Monday, 7 March 2016 07:52:03 UTC, N_Cook wrote:
> On 05/03/2016 17:14, DaveC wrote:
> > Cleaning up an old rotary mode switch used for 5v logic levels. It has some
> > kind of grease in it.
> >
> >

> > ...which has always confused me: grease is an insulator (well, the grease in
> > this switch is--just tested and it's infinite ohms).

> >
> > I read that dielectric grease is good to keep contacts sealed against the
> > elements that have high physical pressure (which overcomes any separation
> > provided by the grease) but that signal and other low voltages grease is
> > contra-indicated.
> >
> > What say y'all?
> >
> > Thanks.
> >
>
> Can we summarise this thread by saying -
> Any grease is better than no grease, in low voltage, wiped contact
> situations, as long as the grease doesn't go hard with age or otherwise
> degrade or corrode the contacts itself

No, definitely not. I often saw grease on contacts in 1950s kit, what happened is it absorbed every kind of dust going and turned into a thick sticky unworkable junk. Switches frequently became almost seized. Dry contacts OTOH oxidise more... ya can't win.

I've always been told only use silicone grease on electricals, others get corrosive when electricity is applied.


NT

[Jim Thompson]

I've been using a silicone spray lubricant on light bulbs threads for
YEARS.

Since I started doing that, no more seized bulbs in the 16' ceiling,
so I can always change with a light pole.

Nothing quite like being that high in the air trying to use a raw
potato to unscrew the remains on a bulb that broke off because the
threads seized :-(

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

[tabb...@gmail.com]

On Monday, 7 March 2016 19:04:05 UTC, Jim Thompson wrote:

Spray lube is presumably a thin oil not grease. I guess it doesn't form the very thick gunk over decades that greases do.


NT

[rickman]

Oil, grease, it's all the same thing. That's why they use graphite in
locks, it doesn't hold dirt like oil and grease do. I expect Jim's
bulbs aren't exposed to a lot of dust and a ceiling socket doesn't have
much fall into it.

--

Rick

[Jim Thompson]

This stuff is so thin you're not aware it's there... unless you
accidentally get some on the tile floor... nasty slippery ;-)

[Jim Thompson]

This is what I use...

<http://tinyurl.com/8apbjn>

For light bulb threads I actually spray onto a paper towel then wipe
the bulb threads.

[DaveC]

> I've always been told only use silicone grease on electricals, others get
> corrosive when electricity is applied.
> NT

I (op) in my research came across this warning (which, of course I cannot
find now): silicone grease in the presence of plasma (ie, arcing switch
contacts and such) turns to silicon dioxide, an abrasive.

[Tauno Voipio]

The burning silicone destroys the contacts building
an insluating layer on the surfaces.

In the early 70's, I worked for an elevator company,
and we started sudenly getting failures in relay-based
elevator group control systems with hundeds of relays.
The failures were non-conducting contacts. After a long
hunt, the cause was traced to silicone-containing hair
spray of the factory workers.

--

-TV

[mixed nuts]

Yup. Quartz is abrasive and the oil can be polymerized and form a
tenacious insulating coating. A number of mil specs prohibit silicones
in electrical equipment for those reasons.

--
Grizzly H.